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Master's Theses Graduate College

12-1999

Quantifying a Key Injection Molding Attribute Defect Quantifying a Key Injection Molding Attribute Defect

Kristopher Bryan Horton

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QUANTIFYING A KEY INJECTION MOLDING ATTRIBUTE DEFECT

by


A Thesis

Submitted to the

Faculty of The Graduate College

in partial fulfillment of the

requirements for the

Degree of Master of Science

Department of Industrial and

Manufacturing Engineering

Western Michigan University

Kalamazoo, Michigan

December 1999

Copyright by Kristopher Bryan Horton

1999

ACKNOWLEDGMENTS

I want to thank my advisor and committee chairperson, Dr. Paul Engelmann

for believing in me and giving his full support for the topic I selected for this thesis.

On several occasions we felt like we may have taken on more than we could handle.

In the long run it was the leadership, guidance and make or break deadlines of

Dr. Engelmann that kept me on track to completion of my graduate work. I want to

express sincere thanks to my graduate committee members, Mr. Mike Monfore,

Dr. David Lyth and Dr. Mitchel Keil, for sharing with me their time and expertise.

Mr. Monfore taught me how to properly analyze the statistical data from my

experimentation. Dr. Lyth's leadership in the realm of quality control was

instrumental in helping me develop a methodology for the visual evaluation of sink

marks. Dr. Keil helped me to analyze the coordinate measurement machine data used

for quantifying sink marks.

I want to thank Johnson Controls, Inc. of Holland, Michigan for allowing me

access to their metrology center, MacBeth SpectraLight equipment, injection molding

presses and employees for my experimentation. My thesis work would not have been

possible without Johnson Controls commitment and financial investment. A special

thanks goes out to Mr. JeffVanderKolk, Mr. Mike Seymour and Ms. Shelly Bangma

of the metrology center. They spent countless hours helping measure parts with sink

11

Acknowledgments-Continued

marks on the coordinate measurement machine. I want to thank Mr. Wayne

Boomsma for helping me to systematically produce parts with various levels of sink

marks on an injection molding press. In addition, I want to thank the one hundred

and eleven Prince employees who agreed to participate in the visual evaluation phase

of my experimentation.

Finally, I want to thank my wife, Lisa. Her commitment to my work and to

me was unfailing. On numerous occasions she spurred me on and encouraged me

when I was just about to give up. Her reward is the thrill of knowing her husband is

finished with his master's degree and can spend more time with her.


iii

QUANTIFYING A KEY INJECTION MOLDING ATTRIBUTE DEFECT

Kristopher Bryan Horton, M.S.

Western Michigan University, 1999

A mounting demand for high quality, low cost plastic injection molded

products brings with it goals such as low or even zero defects. In order to ac�ieve

these types of "world class" expectations, resources are used to monitor and control

variable data such as cycle time, part weight or dimensions. Despite this emphasis on

variable data, parts are often rejected based on attribute molding defects such as sink

marks or splay that are measured by subjective criteria and therefore difficult to

control. Appearance of a part once considered acceptable may no longer be, due to

changing expectations or subjective interpretation of an agreed upon standard.

Sink marks on each part were measured using a coordinate measurement

machine (CMM) and quantified using statistical software. Experimentation was

conducted to identify the level at which a majority of human observers were not able

to visually perceive the sink marks. This threshold could be used to develop an

acceptance standard for the part used in the experimentation. Quantifying an attribute

defect is not intended to be a substitute for preventing defect formation via robust part

design, mold design, choice of polymer, or selection of processing conditions.

TABLE OF CONTENTS

ACKNOWLEDGMENTS ......................................................................................... ii

LIST OF TABLES ..................................................................................................... viii

LIST OF FIGURES ................................................................................................... lX

CHAPTER

I. INTRODUCTION . .. . .. .. .. .. . .. .. . .. . .. .. .. .. .. .. . . . .. .. ... . . ... .. .. . . . . . . .. . ... .. .. . .. .. .. . ... .. . .. . .. . . 1

Background........................................................................................... 1

Problem Statement and Significance .. .. .. .... .. .. .. .. .. .... .. .. .. .... .. .. .... .. .... .. . 1

Summary ............................................................................................... 4

II. REVIEW OF LITERATURE .. .. .. ...... .. ...... .. .... ...... .. ...... .. .. .. .. .. .. ...... .. .... .. ...... 5

Overview............................................................................................... 5

Approaches to Defect Management...................................................... 5

Part Design................................................................................... 7

Mold Design................................................................................. 9

Choice of Polynier ....................................................................... 11

Processing Conditions .................................................................. 11

Masking ........................................................................................ 13

Inspection..................................................................................... 14

Key Elements for Developing Test Methodology ................................ 15

The First Phase: Quantifying Sink Marks ................................... 16

lV

CHAPTER

Table of Contents-Continued

Phase II: Visual Evaluation of Sink Marks................................. 22

Summary of Literature Review............................................................. 30

III. METHODOLOGY ........................................................................................ 32

Introduction........................................................................................... 32

Production of Parts With Sink Marks .. .. .. .. ... .. ... .. . . . .. .. .. .. .. .. ... .. .. .. 32

Visual Evaluation Pilot Tests ....................................................... 36

Production of Parts to Expand the Range of Sink Mark Treatments.................................................................................... 42

Quantification of Sink Marks on Non-Painted Parts ................... 42

Full-Scale Visual Evaluation of Sink Marks on Non-Painted Parts ........................................................................ 46

Production of Painted GDO Doors .............................................. 51

Full-Scale Visual Evaluation of Sink Marks on Painted Parts .... 52

Quantification of Sink Marks on Painted Parts:........................... 52

Analysis of Data........................................................................... 53

Summary of the Methodology.............................................................. 60

IV. EXPERIMENTALRESULTS ....................................................................... 61

Introduction ........................................................................................... 61

Sink Mark Quantification Results ......................................................... 61

CMM Measurement Results ...... .. ..... .. .. .. ..... .. ... ... .. .. .......... ....... .. . 61

Gauge R & R Results................................................................... 66

V


CHAPTER

Visual Evaluation Results ..................................................................... 69

Test Population Attributes ........................................................... 71

Visual Evaluation Pilot Test Results ........................................... 73

Visual Evaluation Results -Painted GDO Doors ........................ 80

Visual Evaluation Results - Non-Painted GDO Doors ............... 83

Summary of Results.............................................................................. 84

V. CONCLUSIONS AND RECOMMENDATIONS ........................................ 86

Conclusions ........................................................................................... 86

Conclusions From the CMM Studies........................................... 87

Conclusions From Visual Evaluation Studies . . . . . . . .. . . .. . . .. .. . . . .. . . . . . 89

Recommendations................................................................................. 90

APPENDICES

Expansion of This Study.............................................................. 90

Implementation in the Manufacturing Environment.................... 93

A. Effron Visual Acuity Wall Chart ................................................................... 96

B. Digital Pictures of Fixture Used for Coordinate Measurement Machine ...... 98

C. Proposal and Forms Submitted to the Human Subjects Review Boardat Western Michigan University .................................................................... 101

D. Surface Scans From Third Measurement Series (Painted and Non-PaintedParts) on Coordinate Measurement Machine ................................................. 110

VI


APPENDICES

E. Surface Scans From First Measurement Series (Non-Painted Parts) onCoordinate Measurement Machine ................................................................ 131

F. Surface Scans From Second Measurement Series (Non-Painted Parts) onCoordinate Measurement Machine ................................................................ 150

G. Overlaid Surface Scans Based Upon Z-axis Values and Residual Valuesfor Parts Measured During Repeatability and Reproducibility Tests ............ 169

H. Results From Visual Evaluation Experimentation for Painted &Non-Painted Parts .......................................................................................... 173

I. Results From Pilot Tests for Visual Evaluation of Sink Marks ..................... 177

BIBLIOGRAPHY ...................................................................................................... 181

vu

LIST OF TABLES

1. Results of Gauge R & R Based Upon Z-axis Values..................................... 68

2. Result of Gauge R & R Based Upon Residual Values .. . . . . .. . . .. .. . . . .. . . . . . . . . . .. . .. . 68

3. Age Ranges of Observers Included in Visual Evaluation Test Population ... 72

4. Overview of Eyesight Status for Observers Included in Test Population ..... 73

5. Number of Years Each Observer Worked in Plastics Industry ...................... 74

6. Occupation for Observers Included in Test Population ................................. 74

7. Results From Observer #1 -Hand Held Observation ................................... 75

8. Results From Rank Order Test by Groupings of Three ................................. 78

9. Results From Rank Order Test by Grouping of Eleven ................................. 79

Vlll

LIST OF FIGURES

1. Primacy of Defect Prevention (Software Quality Assurance, 1998) ............. 6

2. Product Cost Throughout Design Cycle (Savantage, 1998) .......................... 6

3. Rib and Boss Design (General Electric Plastics, 1996)................................. 8

4. Coring (General Electric Plastics, 1991) ....................................................... 9

5. Interference From Division of Wavefront (McGraw-Hill, 1997) .................. 17

6. Interference From Division of Amplitude (McGraw-Hill, 1997) .................. 17

7. Basic Arrangement of a Photoacoustic Microscope (Hoshimiya et al.) . .. .. .. . 19

8. Components of the Loria Laser Gauge (Product News, 1988) ...................... 20

9. Surface Defect Analyzer (NASA, 1997, paragraph 4) .................................. 21

10. Vergence Representation (Lehar, 1998, paragraph 1) ................................... 23

11. Overlapping Opaque Squares .... .. ..... ... .. ............... ............... .... .......... ............ 25

12. GDO Door With Five Sink Mark Areas ........................................................ 34

13. Overhead Assembly With Installed GDO Door ............................................ 34

14. Viewing Fixture Used During Pilot Test #1 .................................................. 38

15. 13-Inch Viewing Slot Fixture ........................................................................ 39

16. Four-Inch Viewing Slot Fixture ..................................................................... 40

17. Surface Scan With the Five Sink Mark Areas . .............. ............. ................... 43

18. Fixture Used During CMM Measurements ................................................... 44

19. Section of Research Questionnaire ................................................................ 48

IX

List of Figures-Continued

20. Surface Scan and Regression Line................................................................. 55

21. Overlaid Surface Scans Based Upon Z-axis Values...................................... 5 5

22. Overlaid Surface Scans Based Upon Residual Values.................................. 56

23. Painted Part Depth Values for Sink Mark Areas 1-5 (ThirdMeasurement Series)...................................................................................... 63

24. Surface Scan Profile for Pack Pressure of 200 psi From ThirdMeasurement Series....................................................................................... 64

25. Surface Scan Comparison Between First and Second Measurement Seriesfor Part Produced With Pack Pressure of 100 psi.......................................... 66

26. Average Measurements Based Upon Z -axis Values ...................................... 70

27. Average Measurements Based Upon Residual Values .................................. 70

28. Results of the Painted Parts Study for Sink Areas #1, #2, #4 & #5 ............... 81

29. Results of the Painted Parts Study Comparing Sink Area #3 to SinkAreas #1, #2, #4 & #5 .................................................................................... 82

30. Results of the Non-Painted Parts Study Comparing Sink Area #3 to SinkAreas #1, #2, #4 & #5 .................................................................................... 83

X

CHAPTER I

INTRODUCTION

Background

Plastics companies are faced with the problem of defective products that do

not meet customer expectations. Many efforts have been made to reduce the impact

of these products. Typical options for their disposition may include reworking,

recycling or negotiating a waiver with the customer. Disposition is usually a

straightforward process as long as there is no question the product is defective.

Problems arise, however, when a defect is on the borderline of what is considered

acceptable. Often these challenges are compounded when dealing with attribute

defects. Attribute defects are characteristics such as appearance that are often

difficult to directly measure. Since they are difficult to measure, the determination of

acceptability is sometimes considered subjective. Regarding attribute defects, Chang

and Tsuar (1995) state that "shrinkage, warpage, and sink marks are the most

important problems of plastic injection molding products" (p. 1222).

Problem Statement and Significance

Attribute defects are often defined with subjective criteria. When subjective

standards are used to determine part acceptability, it is difficult to effectively monitor

1

and control these defects. Many of the monitoring efforts used to detect defective

products are focused on variable data. Measurable characteristics such as time,

dimensions or weight are considered variable data (Muccio, 1991). Leaders in the

field of quality management agree that with such a large emphasis on variables,

attribute analysis may be overlooked.

Unfortunately, it is common to focus monitoring activities on data that are easily gathered rather than important or to concentrate on 'objective' measures that are easily defended at the expense of softer, more subjective data that may be more valuable for control (Meredith & Martel, 1995, p. 446).

Examples of injection molding attribute defects include flash, sink marks,

underfill, burn marks, contamination, splay, or streaking of the surface (Muccio,

1991). Attribute data includes characteristics that are sometimes difficult to directly

quantify. This does not mean that attribute data is synonymous with subjectivity. In

fact, there are several ways to measure attribute data such as rating scales, boundary

samples and go/no-go gauges. Variation is usually not allowed outside of an agreed

upon acceptance standard. But one of the most difficult aspects of dealing with

attribute data is establishing a clearly defined acceptance standard that everyone

understands and interprets the same way.

Attribute defects on injection molded parts may develop during any stage of

the molding process. It is essential to investigate all aspects of the molding process to

accurately identify their root cause. Part design, mold design, process parameters and

material selection should all be considered when analyzing the source of defects. In

some situations, finding the root cause may be difficult. Then it may be necessary to

2

implement an inspection system to contain defective parts. This strategy, while

expensive, is used to lower or eliminate the possibility of sending defective product to

the customer.

There are many consequences ofrelying on subjective acceptance standards

for attribute defects. Customer and supplier may not fully agree on the specific

requirements for what is considered an acceptable product. Requirements

communicated to employees producing the product may be misinterpreted. Rejection

criteria may change throughout the duration of the product's life cycle. This may

lead to increased quality costs due to potential increases in rejection rates at the

customer and supplier's facilities. Additional costs may be incurred through

transporting, inspecting, recycling and replacing the defective product.

One attribute defect, sink marks, was selected for this study because it occurs

frequently and can lead to significant aesthetic and dimensional problems on a part. A

sink mark is "a shallow depression or dimple on the surface of a finished part"

(Ashland Chemical, 1997, paragraph 65). This research was used to establish a

methodology to quantify sink marks and determine a level of sink marks on a

production part below which no observers could see the defect. This quantified sink

mark level could be utilized as a standard of acceptability for the part used in the

studies. The part used in this study was a painted garage door opener (GDO) door.

3

Summary

In summary, an injection molding attribute defect called sink marks was

selected so that a methodology could be developed to quantify the defect. A visual

evaluation was planned to determine the ability of human observers to see sink marks.

The goal was to determine if a quantified level of sink marks could be identified

below which observers could not visually detect the defect. Then an acceptable

standard for the defect on the GDO door could be established.

The chapters that follow describe this study. Chapter II is a review of

applicable literature used to develop the methodology detailed in Chapter III. In

Chapter IV, the results are presented from the studies involving objective

quantification and visual evaluation of sink marks. Conclusions and

recommendations are discussed in Chapter V.

4

CHAPTER II

REVIEW OF LITERATURE

Overview

Literature related to injection molding was investigated to determine what

approaches have been used to resolve attribute defects, sink marks in particular.

Research also revealed key elements that could be used to develop a methodology for

quantifying sink marks. The methodology for this thesis included objective

measurement and subjective evaluation of sink marks. Before presenting literature on

specific injection molding defects, an overview is given below on different

approaches often used to manage defects.

Approaches to Defect Management

Research confirmed that defect prevention (Figure 1) is the optimum approach

for dealing with attribute or variable defects (Software Quality Assurance, 1998). To

be successful at this approach when designing products, engineers need to investigate

areas that could potentially lead to formation of surface defects. If engineers

overlook these areas, it could result in a poorly designed part or mold. Then efforts

may be necessary to eliminate the defect during a later, more costly design or

production stage. Research shows (Figure 2) the costs of design changes rise

5

, ..

Primacy of Defect Prevention

Defect prevention is almost always superior to

defect detection and removal because:

I. defect detection requires time to find defects2. defect detection often requires special tools,

personnel, workspaces, and materials to find defects3. defect detection requires training to find defects4. defect removal requires time to correct defects5. defect removal often requires shipping, special tools,

personnel, workspaces, and materials to fix defects;if defects cannot be fixed, products may be scrapped

6. undetected defects may slip through to the customer,causing loss of money, goodwill, and business

Figure 1. Primacy of Defect Prevention (Software Quality Assurance, 1998).

80% of the cost and performance is set in the first 20% of the design cycle

�

Start Planning

Physical Design

•V -1008060

·Product-4o Cost

(°lo)

Figure 2. Product Cost Throughout Design Cycle (Savantage, 1998).

dramatically the further the product moves toward production (Savantage, 1998).

Due to the high cost and difficulty of most design changes, material or processing

changes are more likely to be selected for correcting a defect (Ezrin, 1997).

6

Logic Design

However, eliminating a defect entirely may not be possible during the latter stages of

a product's design. Then reducing the size or moving the location of the defect may

be the only viable option that remains.

Considerations to prevent, eliminate, or reduce injection molding attribute

defects include part design, mold design, choice of polymer, and processing

conditions (Chang and Tsaur, 1995). In addition, techniques for inspecting or

masking the defect may be employed.

Part Design

Part design features such as ribs, bosses, coring, increased wall thickness and

others are often used to improve a part's strength or functionality. In addition, good

part design can significantly lower the possibility of visual defects forming on the

finished product. Each design feature must be selected and designed carefully for

each product. If basic design standards are violated when designing products, surface

defects could result. For example, sink marks in particular can develop opposite ribs,

bosses or any other design feature if not designed properly (Griffing and Whitaker,

1993).

Ribs are thin walls of plastic used to reinforce a part's strength and reduce

wall thickness. Proper design of ribs can help prevent the formation of appearance

defects such as sink marks (Figure 3). As shown, if the base thickness (t) of a rib is

more than 0.5 times the wall thickness (T), sink marks can develop.

7

Guidelines for Proportioning Ribs

1. Base thickness

2 . Height

3. Comer Radius

4. Draft Angle

5. Spacing

t � 0.5 T

h�3T

r � 0.25 - 0.4 T

0 � 0.5°

S �2T

Suggested Boss Wall Thickness

Boss proportions that usually

provide sufficient strength,

though accompanied by sink

marks and residual stress.

2D

rm

Strong possibility of sink

marks here when W > 0.6T

Figure 3. Rib and Boss Design (General Electric Plastics, 1996 ).

Bosses are typically cylindrical in shape and are used for some type of

assembly function such as screw insertion. Designs of bosses are usually determined

by their intended use such as mechanical assembly (Figure 3). Similar to rib design

requirements, the base of bosses (W) should not exceed 0.6 times the wall thickness

(T) of the part. If the base is greater than 0.6T, a strong possibility exists that sink

marks could develop during molding.

8

0

oss

.______?, ._________, 4~ w4rr-r

Coring is a method of mold design used to provide uniform wall thickness

throughout an entire injection molded part. The use of coring is also effective in

helping to prevent the formation of sink marks (General Electric Plastics, 1991 ). Sink

marks can develop opposite a boss as shown in Figure 4(a). To improve the boss

design, a general design recommendation for coring is shown in Figure 4(b ). The

distance ( d) from the bottom of the core to the opposite part of the wall should be

two-thirds (2/3) of the total wall thickness (T).

(a) Before Coring

Figure 4. Coring (General Electric Plastics, 1991).

Mold Design

Griffing and Whitaker (1993) identify mold design as a key element for

prevention of attribute molding defects. Two mold design features that can

significantly affect the surface quality of an injection molded product are gating and

venting.

9

(b)Bedasign

Gating is an opening in the mold where the liquid resin flows into the cavity

of the mold (Ashland Chemical, 1997, paragraph 28). Proper location of gates is

important to prevent or minimize the formation of visual defects. Gate related defects

such as jetting, splay, gate blush or other visual defects could be minimized by

locating the gate at a right angle to the runner. In situations where changing gate size

is unsuccessful, gates may be relocated so resultant defects are located on an area of

the part where surface quality is not critical. Another defect impacted by gate

location is weld lines. Weld lines are created when two flow fronts of plastic meet

and join together in the mold cavity. To reduce the size of weld line formation, gates

should be located in such a way as to allow flow of resin from thick to thin sections

within the mold (General Electric Plastics, 1994).

Venting allows gas built up during packing to escape from the mold cavity.

This gas, if not properly vented, can lead to the formation of surface imperfections

(Filbert and Roder, 1963). If vents are too large, flash may develop at the vent where

the two mold halves separate. If vents are too small, the gas trapped inside the mold

cavity could cause plastic degradation during molding of the part. The resulting

defect, burn marks, is usually seen on the surface of the part and is brown or black in

color. Using properly designed vents along the parting line (where the two mold

halves join during molding) can prevent these types of surface defects.

10

Choice of Polymer

Selection of polymers or polymer additives can directly affect the surface

quality of a product. Chang (1994) demonstrated the potential effects of additives

upon surface quality of a part. The study focused on the formation of a surface defect

called jetting, which is an abnormal flow pattern in the resin that resembles a snake.

Jetting is usually caused by inadequate mold design, including improper gate size or

varying gate size where a thin section of the cavity suddenly becomes wider (Ashland

Chemical, 1997, paragraph 35). In the study, the root cause of the problem was

directly related to the material itself. To help correct the problem, a polymer additive

(polystyrene-maleic anhydride-methyl methacrylate) was introduced at various levels

into a rubber-modified thermoplastic. As the level of additive increased, the amount

of jetting decreased. Chang's study underscored the importance of understanding

how the surface quality of the product may be affected by the choice of polymer or

additives.

Processinfi Conditions

One of the main approaches for preventing or eliminating attribute molding

defects involves the optimization of process parameters on the injection molding

press. Process parameters can be optimized through designed experiments (Ari,

Wilson and Zou, 1993). Even when starting with optimum parameters, defects may

develop over time due to normal wear of a mold or components on the injection

11

molding press. Therefore, on-going optimization may be necessary to eliminate any

defect formation.

If elimination of the defect is not possible, then the goal of process

optimization should be to minimize the size or move the location of the defect. In

some cases, the defect can be moved to an area that is less visible on the end product.

This approach may not address the root cause of a defect but can serve as a temporary

means of dealing with the symptom until a permanent solution is implemented. The

following examples show how injection molders have used processing conditions to

address various injection molding defects.

Ari et al. (1993) investigated an injection molding attribute defect called short

shots. Short shots result when the cavities inside the mold are not completely filled

with plastic during the molding cycle (Ashland Chemical, 1997, paragraph 59). The

short shot problem developed into a serious one when the defect rate reached five

percent and the company had to dedicate one employee to 100% inspection. The

company was subsequently able to establish a robust process by selecting the level of

cut-off pressure that actually prevented the formation of short shots.

Jan and O'Brien (1992) discussed how a company used a system to reduce

surface defects during the injection molding of plastic products. The system was

based on a software program that asks the operator a series of questions about the

current operating parameters and the resultant surface quality of the product. Based

upon these inputs, the system gave recommendations for process adjustments in order

to improve the surface defects on the part. The software was not designed to quantify

12

the attribute defects that appeared on the parts produced. Instead, the operator based

adjustments to the process upon subjective evaluation of the product. This system did

appear to be effective at eliminating or reducing a defect after it had developed.

Masking

One of the most common ways of masking attribute defects, especially when

dealing with automotive interior trim, is to paint the part. The primary reasons for

painting plastic parts for an automotive interior are to achieve consistent color and

gloss levels. Additional advantages include the ability to mask or cover over

common surface defects such as splay, flow lines, or blush on the molded part.

Despite these advantages, there are some defects such as sink marks that cannot be

masked with paint. In addition, in order to lower costs, the industry is beginning to

eliminate the painting of many plastic interior parts. Therefore, painting to mask a

defect's impact has become a less attractive option. This has placed greater pressure

on injection molders to understand their processes in order to produce defect-free

products.

Another method used to mask surface defects is texturing. Griffing and

Whitaker (1993) explained how the use of texture improves overall surface

appearance when used to mask weld lines and gate blush. In addition, sink marks

were evaluated on parts that had both a textured and non-textured half. The sink

marks were less visible on the side with the textured half. This study confirmed that

texturing can be an effective method for masking surface defects.

13

Inspection

In cases where surface defects cannot be prevented, eliminated or reduced,

some method of inspection may be necessary to avoid sending defective products to

the customer. In order to detect defective products, criteria must be established to

reveal what is an acceptable part. Once the suitable criteria are established, they can

be used to sort out nonconforming parts.

Establishin& Inspection Criteria

Inspection criteria can be defined as a set of standards or rules that determine

if a defect, such as sink marks, is acceptable. Inspection criteria can be established

using several different methods. The following are a few of the common methods

used.

Rating scales are used to assign a numerical value to an observable defect.

Griffing and Whittaker (1993) demonstrated an example ofthis in which five color

and appearance experts evaluated sink marks. After viewing parts with varying

degrees of sink marks, the evaluators rated the sink marks using a scale of one to five.

A rating of five represented a part with no visible sink marks. A rating of one

represented a part with highly visible sink marks. This procedure provided the

evaluators a method to make an informed decision on which parts were acceptable.

14

Boundary samples provide a way to visually show the minimum and

maximum limits of what is an acceptable part. This method is widely used in the

automotive industry for injection molded parts.

Go/no-go gauges may involve a pin gauge that has a minimum dimension at

one end and the maximum dimension at the other. Another go/no-go gauge used in

industry is sight lines. Minimum/maximum sight lines are etched into the metal of a

fixture and typically following the expected profile of a part. If the profile of the part

does not fall within the minimum and maximum sight lines, the part is rejected.

The two inspection methods used in this thesis study to evaluate sink marks

were: (1) an objective measurement system, and (2) visual evaluation by observers.

Both of these methods are discussed in the next section called Key Elements for

Developing Test Methodology, which is focused on research of key elements and

equipment for establishing a systematic approach for quantifying sink marks.

Key Elements for Developing Test Methodology

Whelan and Goff (1996) stated that when dealing with defects, "a logical and

systematic method of dealing with faults is most desirable" (p. 102). Based on this

statement, a review of applicable literature was conducted in order to establish a

systematic methodology to study sink marks. The test methodology for this thesis

consisted of two different phases.

The first phase, quantifying sink marks, involved using an existing

measurement system to measure sink marks on the surface of a plastic injection

15

molded part. Research for the first phase included various measurement systems that

could potentially be used to quantify sink marks. The second phase included

exploration of key elements such as eyesight cues, lighting, and distance of

observation that might impact the test methodology.

The First Phase: Quantifying Sink Marks

Six different objective, instrument-based measurement systems or devices

were researched to determine their usefulness to quantify sink marks: (1)

interferometers, (2) optical comparators, (3) photoacoustic microscopes, (4) laser

gauges, (5) def�ct analyzers, and (6) coordinate measurement machines. The six

systems evaluated are described below.

1. An interferometer is an instrument that can be used to measure

deformation, vibration, and contour measurements of diffuse objects (McGraw-Hill,

1997). There are several types of interferometers that can be used for wide range of

applications including surface measurements and determining the distance between

stars. Interferometers fall into two categories: (1) division of wavefront (Figure 5),

and (2) division of amplitude (Figure 6). One advantage of using an interferometer to

measure sink marks is its ability to detect surface change. Advanced equipment is

capable of measuring surface roughness with a resolution of about one nanometer ( 40

billionths of an inch). This high resolution was not required for measuring sink

marks. There were some disadvantages of using an interferometer to quantify sink

marks. For example, the equipment is sensitive to air currents, acoustic noise,

16

· )))point

source I� two pinholes interference of

two spherical waves

Figure 5. Interference From Division of Wavefront (McGraw-Hill, 1997).

two virtual

images of point

source

Fig. 2. Division of amplitude.

glass plate

Figure 6. Interference From Division of Amplitude (McGraw-Hill, 1997).

humidity, and temperature. These disadvantages would make it difficult to utilize an

interferometer for this study.

2. An optical comparator magnifies a feature of a part and displays it on a

17

viewing screen for comparison to a master outline of a desirable part. The shadow of

the part being measured must fall within specification limits in order to pass

inspection. It is typically used to compare contours or dimensions (Wortman, 1995).

Optical comparators are one of the most reliable and accurate measurement tools for

manufactured parts (Kendrick, 1994). Because the system is based upon a visual

comparison to a master part, the optical comparator is not ideal for producing a

quantitative measurement of sink marks. Also, the optical comparator does not have

the necessary measurement discrimination to quantify sink marks.

3. A photoacoustic microscope uses an Ar-ion laser beam along with optical

scanners to obtain amplitude and phase images. These images are used to produce

precise, quantitative shape and depth measurements of surface defects (Hoshimiya,

Endoh and Hiwatashi, 1996). The basic arrangement of a photoacoustic microscope

is shown in Figure 7. One advantage in using a photoacoustic is its ability to identify

both the location and shape of a defect on the surface of a part. However, most

systems are only capable of qualitative analysis. Therefore, a photoacoustic

microscope is not the optimum equipment for quantifying sink marks.

4. A laser gauge, the Loria analyzer, was developed by Ashland Chemical to

check Class A surfaces and produce a quantitative rating of the surface quality. An

advantage of using the laser gauge for measuring sink marks is its ability to detect

and quantify surface defects. A helium-neon laser beam scans the surface area. The

laser beam measurements are reflected onto a projection screen. It is recorded by a

high-resolution video camera and analyzed by the system's computer (Product News,

18

Oscillator

Lock-in Amp

A/D Converter

Mechanical X-Y Scanner

Display

Personal com uter

'-=�---tScanner -----1driver

t----Jl-.t D/A Converter

Figure 7. Basic Arrangement of a Photoacoustic Microscope (Hoshimiya et al.).

1988). A typical analysis requires up to four minutes to complete. A computer is

used to compare the waviness or variation of a measured scan to a theoretical

standard. The difference between the measured scan and the standard scan results in

a value for variation. The lower the value, the smaller the amount of variation along

the scanned surface. The components of the Loria surface analyzer are shown in

Figure 8.

5. The surface defect analyzer was developed by the National Aeronautics

and Space Administration (NASA). It creates a profile of the defect using the

technique of structured light microscopy. The system consists primarily of

19

Computer (Digitizes

Line Image)

Laser

Printer

Video Camera

Projection Screen

Figure 8. Components of the Loria Laser Gauge (Product News, 1988).

commercially available components. A television camera provides an image that is

placed on a monitor screen of a computer. A video micrometer is used on the image

to quickly provide accurate measurements of width and depth. The system shown in

Figure 9 is portable and can store records permanently for future use (NASA, 1997,

paragraph 4). The advantage of using the surface defect analyzer to measure sink

marks is its ability to accurately measure dimensions, surface flaws, and defects. The

system has been used to analyze damage on critical surface of the Space Shuttle.

6. A coordinate measurement machine (CMM) is a three-dimensional height

gauge that can be used to measure almost any dimension on an object. CMMs

provide data that can be used for process control or to make adjustments to correct

20

.....__~ I p

Figure 9. Surface Defect Analyzer (NASA, 1997, paragraph 4).

visual or dimensional defects (Chameleon CMM, 1996, paragraph 4). One useful

method of a CMM involves using ordered measurements to create a surface model of

a part. This surface model can then be compared to computer-aided design (CAD) to

show deviations from the original design (Menq and Chen, 1996, paragraph 1 ). One

challenge when using CMMs for quality control purposes is that measurement data

usually is not provided in a timely manner for process control to be utilized (Bosch,

1992). In order to use CMMs for process control in the manufacturing environment,

suppliers have begun to produce robust portable CMMs that can be integrated into

shop floor operations (Bosch).

The CMM was selected as the measurement device to quantify each of the

five sink marks areas on the GDO door. The reasons for selecting the CMM and its

capabilities in terms of measuring each sink mark area are discussed in Chapter III

(Coordinate Measurement Machine Studies).

21

Phase II: Visual Evaluation of Sink Marks

During this study, visual evaluation of sink marks by humans was categorized

into two areas: (1) eyesight factors, and (2) preference and discrimination

procedures. The goal of the research was to pinpoint the elements that should be

included during visual evaluation of sink marks, in order to reduce subjectivity.

Eyesight Factors

Research was conducted to determine the eyesight factors that might influence

an observer's ability to perceive sink marks. Three eyesight factors were

investigated: (1) depth perception, (2) visual acuity, and (3) external factors.

Depth Perception. During the investigation, binocular (two eye) cues were

determined to influence a person's ability to perceive depth (Depth Perception, 1996,

paragraph 2). Binocular vision relates to the coordinated use of both eyes to focus at

a common target. Three binocular cues investigated in the research were: (1)

vergence, (2) stereopsis, and (3) depth judgment.

Vergence is the only binocular cue that gives absolute depth information.

Vergence consists of the "muscular feedback from effort to converge or diverge

which gives information about depth" (Depth Perception, 1997, paragraph 2). In

other words, it is the angle ofvergence between the two eyes when an object is at a

22

point in space (Figure 10). There is a large vergence when viewing objects that are

close and smaller vergence for objects further away.

The second cue, stereopsis, involves the use of binocular vision in order to

produce three-dimensional vision (Cobo-Lewis, 1997, paragraph 1). The use of only

one eye is termed monocular vision. With monocular vision, the ability to see in

three dimensions may be impaired. In some cases, people may have one eye that is

impaired or even blind.

object at infinity, zero vergencefar o�ect : small ---...., vergence : ♦

' " , '

near object : ! \ large '-...._ : r--\ vergence � \.

1' , \ ••

�,:,'--..-,>

.. �

oo�eyes

distance

Figure 10. Vergence Representation (Lehar, 1998, paragraph 1).

► 0()

The third binocular cue is accuracy of depth judgments. Since sink marks

consist of a shallow depression or dimple, there is a measure of depth associated with

the defect. Therefore, it is reasonable to conclude that the ability to perceive depth is

critical to inspection of sink marks. The more difficult question is how depth

perception influences the ability to detect sink. The following two topics help explain

this.

23

Autostereograms are related to depth perception and involve the viewing of 3-

D stereograms. "In 1994, America became addicted to autostereograms - those

swatches of psychedelic wallpaper that dissolve into three dimensional images when

you stare at them long enough" (Zimmer, 1995, paragraph 1). Scientists have

realized that depth perception arises from the way the brain compares signals from

the two eyes, which see an object from slightly different angles (Zimmer, paragraph

2). This involves what is known as binocular disparity. Binocular disparity refers to

how each eye perceives an object from different viewpoints. "Thus, the images

projected onto the retinas are slightly different. The brain uses assumptions of depth

to reconcile the disparity" (Murray, 1997, paragraph 15). The balance of disparity

between two eyes is disrupted when one eye is more dominant than the other.

Gestalt principles are also related to depth perception and reveal the "tendency

to seek organization and closure, recognize patterns, and so on" (Murray, 1997,

paragraph 10). For example, when observers view a drawing of two partially

overlapping opaque squares where one obscures a comer of the other such as in

Figure 11, it will be seen as overlap and not as an L-shape abutted to the edge of a

square (Murray, paragraph 10).

Gestalt principles were investigated because the possibility exists that an

observer evaluating sink marks may have a tendency to overlook the defect due to the

Gestalt tendency to seek organization and closure. In 1960, Bela Julesz concluded

"that depth perception is one of the first things the brain extracts from the visual

signal, by comparing the left-eye and right-eye images dot by dot. Object recognition

24

Figure 11. Overlapping Opaque Squares.

must come later" (Zimmer, 1995, paragraph 3). In a rebuttal to Julesz's conclusion,

Vilayanur Ramachandran created a stereogram out of an optical illusion. The key

element of this stereogram involved three circles which had a wedge cut out of each.

The people saw the illusory triangle floating in 3-D even though the gaps prevented them from making the point-by-point comparison of left and right images that Julesz thought was essential to depth perception. Although Bela Julesz can be considered the grandfather of the autostereogram craze, it turns out he wasn't entirely right about how the brain perceives 3-D objects (Zimmer, paragraph 5).

These principles may have to be taken into consideration when analyzing data from

visual observations of attribute defects such as sink marks.

Visual Acuity. The final eyesight factor to consider is that of visual acuity.

Acuity is the ability of the eyes to detect detail or sharpness. One method of testing

visual acuity is through the use of a standard optometric eye chart (Appendix A).

25

This method was used to categorize people into different levels of eyesight for the

visual evaluation of sink marks.

External Factors. Two external factors were included in the visual evaluation

of sink marks: (1) lighting environment, and (2) distance from the observer to the

object. A consistent lighting environment was established to minimize variability

during visual evaluation of sink marks. With respect to distance, Nakayama and

Shimojo (1992, paragraph 21) confirmed that viewing distance from observer to

object affects the observer's ability to perceive visual surfaces. Surfaces appear

flatter when viewed from greater distances.

Preference and Discrimination Procedures

For sensory related research, several different types of discrimination and

preference testing procedures are available (Johnson, 1996), including but not limited

to: (a) paired comparison, (b) triangle, (c) repeat pair, (d) double pair, (e) triad, and

(f) dual triad. When discrimination and preference types of testing procedures are

used, there can be several objectives: (a) measurement of product preference, (b)

determination of the reason for product preference, and ( c) assessment of the extent to

which individuals can actually tell the difference between products. The criteria that

were required for this thesis involved the ability to discriminate between various

levels of sink marks. The procedure selected for the visual evaluation study was a

26

simple complete block design. The following are explanations of preference

procedures and complete block designs.

Paired Comparison Procedure. When using this procedure, observers are

given two parts to observe in order to determine which one is preferred. The

procedure does not provide detailed information on discrimination. If one part is

picked more strongly, then it can be concluded that some of the observers are able to

tell the difference between the two parts (Johnson, 1996). The only discrimination

information provided is if one part is strongly preferred. This procedure is not

designed for use with more than two parts (Johnson). Accordingly it could not be

used for this research project.

Triangle Procedure. In the triangle procedure the observer is given three

parts. Two of the three are the same. The observer is asked to select which of the

three parts is different from the others. The observers can then be divided into two

groups: (1) those who correctly choose the unique part, and (2) those who incorrectly

choose one of the parts that are the same. (Johnson, 1996). The triangle procedure

does not indicate observer preference, but is used to determine to what extent the

respondents are able to tell the difference between parts. This procedure is typically

used for two treatments and therefore was not the best choice for this study.

Repeat Pair Procedure. In the repeat pair procedure observers are asked to

view two parts and choose which one they prefer. Next, the observers are given two

27

more parts, identical to the first set of parts, and asked to choose which they prefer.

Three categories ofresponse result: (1) those who select the same part in both tests,

(2) those who prefer the other part in both tests, and (3) those who choose different

parts in each test. (Johnson, 1996). An indication of both preference and

discrimination result from the use of the repeat pair procedure. This procedure is also

used for two treatments.

Double Pair Procedure. The double pair procedure involves observation of

four parts simultaneously. The four parts are actually two pairs of parts identical to

each other. The observer, not knowing that any of the parts are identical, evaluates all

four parts simultaneously and is asked to choose the two most preferred. Observers

are grouped into three categories: (1) Those who choose the first set of identical parts,

(2) those who choose the second set of identical parts, and (3) those who choose two

different parts (Johnson, 1996). The double pair procedure also provides information

on both preference and discrimination. This procedure is also used for two

treatments.

Triad Procedure. The triad procedure provides both discrimination and

preference information. Three parts are given to the observers. Two of the three

parts are identical. Respondents are asked to rank the three parts in order of

preference. The observers are again grouped into three categories: (1) those who

truly prefer the identical parts who will rank both of them higher than the unique part,

(2) those who truly prefer the unique part who will rank it above the identical parts,

28

and (3) those who cannot discriminate and rank the unique part second of the three

(Johnson, 1996). This procedure is also used for two treatments.

Dual Triad Procedure. The dual triad procedure involves two sets of the triad

procedure described above. However, the unique part in the first triad becomes the

identical pair in the second triad, and vice versa. Observers are again categorized into

three groups: (1) those who truly prefer the identical pair in the first triad and the

unique part in the second triad, (2) those who truly prefer the unique part in the first

triad and the identical pair in the second triad, and (3) those who respond randomly.

The benefit of the dual triad over the single triad procedure is that those with firm

preferences are more clearly distinguished. However, it is less convenient to

administrate than the single triad method (Johnson, 1996). This procedure is also

used for two treatments.

Simple Corrwlete Block Design. A simple complete block design involves

presenting each subject with treatments usually in random order (Gill, 1978). An

example of a treatment would be presenting human observers plastic parts with

varying levels of defects for observation. Complete block designs help to conserve

resources ( e.g. the number of people tested or expense of the testing) and reduce

experimental error while maintaining the sensitivity of an experiment (Gill). This

design can be used for more than two treatments and thus a good choice for this

research project.

29

When these types of experiments are used, it is sometimes necessary to

remove possible nuisance variables. The concept of a nuisance variable can be

illustrated through the example of various observers in different lighting conditions

viewing plastic parts with surface defects. Some observers may be able to see the

defects while others may not. The nuisance variable in this example is an

inconsistent lighting environment in which the parts were observed. Requiring all

observers to view the plastic parts using the same lighting environment would

eliminate the nuisance variable of inconsistent lighting. If the nuisance variable was

inadequate lighting, a test could be conducted using various lighting conditions to

determine which light source enabled observers to optimally see the defect.

Summary of Literature Review

The review of literature confirmed that defect prevention is a better approach

than elimination or reduction of the defect after it appears. If prevention is

economically or otherwise unfeasible, then elimination or reduction of the defect may

be needed. Elimination and reduction efforts often involve a change in part design,

mold design, choice of polymer or optimization of process parameters. Sometimes

these options may not eliminate the defect but only reduce its size or location. If the

defect can not be eliminated, then methods to mask over the defect ( e.g. painting the

part) are sometimes used. During efforts to eliminate or reduce the defect, inspection

of the molded product may be needed to prevent defects from being sent to the

30

customer. When inspection is needed, then it becomes necessary to clearly define the

inspection criteria so that an objective acceptance standard is established.

31

CHAPTER III

METHODOLOGY

Introduction

There were two phases involved in the methodology of this study. The

purpose of the first phase was to develop a method to objectively measure sink marks.

The second phase investigated the subjective human component of visual evaluation

to determine if observers were able to reliably detect different levels of sink marks.

The methodology for both phases consisted of the following nine elements:

(1) production of parts with sink marks, (2) visual evaluation pilot tests, (3)

production of parts to expand the range of sink mark treatments, ( 4) quantification of

sink marks on non-painted parts, (5) full-scale visual evaluation of sink marks on

non-painted parts, (6) production of painted GDO doors, (7) full-scale visual

evaluation of sink marks on painted parts, (8) quantification of sink marks on painted

parts, and (9) analysis of data.

Production of Parts With Sink Marks

An injection molding press produced plastic parts with various levels of sink

marks. Before parts could be produced, several elements of the methodology had to

be addressed. These elements included: (a) part selection, (b) production equipment,

32

( c) independent process variable, ( d) part production, and ( e) part labeling and

packaging.

Part Selection

A garage door opener (GDO) door (Figure 12) met these requirements and

was selected for the study on the basis of the following factors. It could be produced

with a level of sink marks that could be detected by the measurement system used in

the study and the human eye. It also could be produced with no visible sink marks by

manipulating process parameters. It had a textured surface common to those used on

many interior automotive parts. The garage door opener is installed behind the GDO

door. The customer pushes on the GDO door to make physical contact with the

garage door opener and initiate the electronic sequence required open a garage door.

The GDO door is assembled into an overhead system (Figure 13) before being

installed into the overhead of the vehicle. Five potential sink mark areas are shown

on the GDO door in Figure 12.

After part selection was completed, the next step was to identify the

production equipment needed to produce GDO doors with various levels of sink

marks.

Production Equipment

The production equipment used to mold the product was a 220-ton hydraulic

clamp Cincinnati injection molding press. The press had a 20-ounce capacity

33

34

Figure 12. GDO Door With Five Sink Mark Areas.

Figure 13. Overhead Assembly With Installed GDO Door.

capacity injection unit, fluid drive screw motor, eagle mixing screw, an LID ratio of

20: 1, intensification ratio of 9: 1, compression ratio of 2.5: 1 and a maximum hydraulic

pressure of 2,500 psi.

After identifying the production equipment, the next step was to identify the

independent process variable that would significantly affect sink mark formation.

Selection of the independent process variable is described in the next section.

Independent Process Variable

One independent variable, pack pressure was selected for the study. Through

research, pack pressure was identified as a significant contributor for controlling sink

marks (Celstran, 1997) as one of the primary injection molding parameters used to

troubleshoot sink marks. Pack pressure is the amount of pressure used to fill out the

mold cavity after first stage injection is complete (Groleau, 1996). The only issue to

determine was the level of pack pressure at which sink marks began to appear on the

surface of the product. Since this level was not completely identified, a preliminary

study was conducted to determine it.

Part Production

Pack pressure was initially set at the top level of 1750 psi so that acceptable

parts with no apparent sink marks were produced. The process was allowed to

stabilize before parts were collected. Two consecutive parts were collected, labeled

and allowed to cool. The pack pressure was then lowered 50 psi to the next level and

35

the procedure repeated. Thirty-six parts (within a pack pressure range of zero psi to

1750 psi by increments of 50 psi) were initially produced for the visual evaluation

study.

Product Labeling and Packaging

During each level, the two consecutive parts produced by the press were

labeled with the level of pack pressure, followed by a hyphen, followed by the part

number within that level (e.g. 50-1, 50-2, 1000-1, 1000-2 ... ). The parts were labeled

on the backside to avoid contamination of the show surface of the part.

The show surface was the textured side of the part that would be visible to the

customer after installation into a vehicle. All parts were allowed to cool for at least

fourteen days to assure that the majority of shrinkage had taken place. All parts for

each level were packaged in foam padding and placed in a cardboard box to protect

their surfaces from damage prior to visual evaluation of the sink marks.

Visual Evaluation Pilot Tests

In order to prepare for a visual evaluation of parts with sink marks, three pilot

tests were conducted. All three pilot tested were completed using non-painted GDO

doors. The first two pilot tests were completed to determine whether observers

should view parts while holding them in their hands or within a viewing fixture.

During the third pilot test, two different tests were used to evaluate how observers

ranked the parts in order of preference (no visible sink to worst visible sink).

36

Pilot Test #1

The first pilot test consisted of two different methods for presenting parts to

observers: (1) hand-held observation, and (2) observation of parts in a viewing

fixture. During the testing using both methods, observers were presented eleven non

painted parts, one at a time, for observation of sink marks. The testing information

specific to each method is presented below.

Hand-held Observation. The hand-held method was evaluated because it

represented how parts are normally observed in production. Observers were asked to

view the parts in a hand-held position and record on the check sheet (Appendix C)

whether they could see sink marks on the parts. They could pick up the parts and

observe them at any angle. They were not allowed to feel the sink marks on the parts

with their fingers. All observers responded favorably to the option of being able to

pick up the parts and visually evaluate them.

Observation Using a Viewing Fixture. This method involved using a fixture

to nest the part (Figure 14). The fixture was used to reduce the amount of variation in

how observers viewed the parts by controlling the distance and angle of observation.

During evaluation by observers, each of the eleven parts were placed into the slot for

viewing. A small section of the part where the sink marks were located was still

visible to the observers. A part was placed into the fixture and viewed by observers

without picking it up with their hands.

37

Part placed into slot for visual evaluation of sink marks

. .

. . . . : .,. ... ......... ·······�·:', ...... ........ ........ ,.

Observers viewed parts from this direction

Figure 14. Viewing Fixture Used During Pilot Test #1.

Pilot Test #2

The second pilot test included evaluation of three different methods for

presenting non-painted parts to observers: (1) 13 inch viewing slot, (2) four inch

viewing slot, and (3) rank order testing. In the first pilot test, observers were allowed

to handle the parts while viewing them. In the second pilot test, some additional

testing using a viewing fixture was completed in an attempt to optimize the viewing

distance and angle of observation. Two nests were constructed out of cardboard to

establish a consistent distance and angle for viewing of the parts. A cardboard nest

was placed vertically at the front edge of the Macbeth viewing table to maintain a

consistent distance between the part being observed and the eyes of the observer.

Both the 13-inch viewing slot and four-inch viewing slot testing utilized the

cardboard nest. Details for the first two methods are provided below.

38

13-Inch Viewing Slot Test. In this test, a viewing slot was cut into the

cardboard nest with dimensions of 13 inches wide and one inch high, as shown in

Figure 15. The wide viewing slot was designed to give each observer greater

freedom of eye and head movement (left to right) when viewing the parts. The 13

inch viewing slot allowed observers to change the angle of observation when viewing

parts for sink marks. Also included in this test was a second cardboard nest used to

maintain a consistent distance between the observer and part being viewed. This nest

was eight inches wide by 14 inches long and included a square opening cutout in

which to place each part for observation. Each part was placed into the cardboard

nest for observation. Observers were presented eleven non-painted parts, one at a

time. Observers were asked if they could see sink marks on each part they viewed. If

they saw sink marks, they were asked where they saw them and in how many places.

13" wide ----+J j.__ I◄

T .---, , . -. -..1 I viewmg s ot 1" high

Figure 15. 13-Inch Viewing Slot Fixture.

Four-Inch Viewing Slot Test. The width of four inches was selected to reduce

the angle of observation (left to right), causing observers to look at the parts straight

39

on. The four inch viewing slot test included the nest as shown in Figure 16, except

the nest with a viewing slot was re-designed by narrowing its original width of

thirteen-inch slot to four inches. In the same way as with the 13-inch viewing nest,

observers were presented eleven non-painted parts, one at a time. Each part was

placed into the second cardboard nest for observation. Observers were asked if they

could see sink marks on each part the viewed. If they could see sink marks, they

were asked where they saw them and in how many places.

i--1 �'wide

T� 1" high viewing slot

Figure 16. Four-Inch Viewing Slot Fixture.

Pilot Test #3

The third pilot test involved presenting non-painted parts to observers and

asking them to rank them in order of preference. Two different groupings were used

when presenting parts to each observer: (1) groupings of three, and (2) group of

eleven.

40

Groupings of Three. The 1ank order test by grouping of three involved

presenting observers four sets of three parts each. When viewing a set of three parts,

observers were asked to rank the three parts from most preferred (less sink or no sink)

to least preferred (more sink). The four sets of three parts were presented in the

following groupings of injection molding pack pressure: (a) 1000 psi, 1150 psi &

1450 psi; (b) 1300 psi, 700 psi and 1750 psi; (c) 250 psi, 850 psi and 1750 psi; and

(d) 1600 psi, 550 psi and 400 psi. The four sets were grouped to establish a small,

medium and large pack pressure range. The pack pressure range equalled the

difference in pack pressure between the highest and lowest parts within each set of

three parts. In group (a) above, a small pack pressure range was established (450 psi).

In groups (b) and (c) above, a medium pack pressure range was established (1050 psi

and 1200 psi). In group (d) above, a large pack pressure range was established (1500

psi). Each set of three parts was randomly presented to each observer for evaluation.

Each observer was allowed to pick up the parts while viewing them for sink marks.

Group of Eleven. The rank order test by group of eleven involved presenting

observers eleven non-painted parts with different levels of sink marks. The eleven

parts were randomly mixed according to their pack pressure and then presented to

each observer for evaluation. Each observer was asked to rank the eleven parts from

left to right in order of preference. The part furthest on the left was the most

preferred and should have had no sink marks present. The part furthest to the right

was the least preferred and should have had the deepest sink marks present.

41

•

Production of Parts to Expand the Range of Sink Mark Treatments

During the three pilot tests, it was discovered that a majority of observers

could see sink marks on the parts produced within the pack pressure range of 150 psi

to 1750 psi. In order to address this issue, additional non-painted GDO doors were

produced at pack pressures of: 1900 psi, 2050 psi, 2200 psi, and 2350 psi. An

attempt was made to produce GDO doors at pack pressures higher than 2350 psi but a

defect called flash began to appear along the parting line edges of the parts. These

parts were produced to provide additional sink mark treatments at the lowest

measurable levels. The goal was to produce parts with no visible sink marks for

inclusion in the full-scale visual evaluation study.

Quantification of Sink Marks on Non-Painted Parts

In order to quantify sink marks, several studies were completed, including:

(a) coordinate measurement machine (CMM) studies, (b) a gauge repeatability and

reproducibility (gauge R & R) study, and (c) statistical analysis of CMM data.

Coordinate Measurement Machine Studies

The system used for measurement of sink marks was a Mitutoyo CHN 1000

. coordinate measurement machine (CNC CMM, No Date). The CMM was selected

for its capability to conduct a series of repeatable measurements across the surface of

a part (surface scan). The profile of a surface scan with the five sink mark areas is

42

shown in Figure 17. The CMM had the capability to be programmed with a standard

surface scan consisting of a defined number of measurements with a consistent

interval (distance between measurements). This program provided a way to

consistently measure each of the parts used in the study. Another reason for selecting

the CMM was its ability to output data that were translatable into statistical software

for analysis. The following steps were used to complete CMM studies.

Sink Area 1

1.5000

1.0000

S 0.5000

=

....

5 0.0000

-0.5000

Sink Area 3 Sink Area4

Scan Point Number

Figure 17. Surface Scan With the Five Sink Mark Areas.

Sink Area 5

All the GDO doors were measured using a . 7 mm Renishaw TP2 probe with a

ruby ball stylus. The TP2 probe is the industry standard for CNC and DCC machines

43

1

35

69

103

137

171

205

239

273

307

341

375

409

443

477

511

Dim

so

m

)

(Probing for Productivity, 1998). According to Renishaw, ruby ball stylus are

suitable for most standard measurement applications.

Before the surface scans were completed, a gauge fixture was constructed to

nest the GDO doors during CMM measurements. The CMM was used to complete

surface scans consisting of200 to 500 measurement points along the X-axis. Each

surface scan consisted of a series of X, Y and Z-axis measurement points on the

surface of the part (Figure 18). During this study, measurements were taken along the

X-axis at .2000 mm intervals (distance between measurements). The Y-axis was held

constant during the measurements. These data values on the Z-axis were a measure

of the variation along the surface of the part including the sink mark areas.

Net Pin #1

Figure 18. Fixture Used During CMM Measurements.

Net pins

for Z-axis

The measurement fixture consisted of three vertical net pins on the surface of

a gauge plate (Figure 18). The part to be measured was located in the Y direction by

44

Point Of

Origin

nesting it against net pins #1 and #2. In a similar fashion, the part was located in the

X direction by nesting it against net pin #3. The Z direction was established by

locating the part on three vertical net pins located in the center of the gauge plate

(Figure 18). Additional pictures of the fixture are presented in Appendix B. Once the

part was located onto the fixture, an X-axis was created between net pins # 1 and #2

using the CMM probe. A Y-axis was established perpendicular to the X-axis created

between net pins #1 and #2. The intersection of the X-axis and Y-axis was then

established as the point of origin (X = 0.0000 mm, Y = 0.0000 mm, and Z = 0.0000

mm). Once the point of origin was established, the CMM was programmed to move

to the first X, Y and Z location on the surface of the part to take a measurement.

Moving the CMM probe in the X direction completed the surface scan for the

remaining measurements. During the final measurement series, the distance between

measurements along the X-axis was .2000 mm.

GaugeR&R

In order to determine the repeatability of the measurement system used to

measure sink marks, a gauge R & R study was completed. Three replicate surface

scans were conducted on the CMM for parts produced at 100 psi, 1000 psi and 1900

psi. Each part was measured three times in random order. The parts were removed

from the fixture after each of the three measurement series. This gauge R & R was

based upon the raw Z-axis values.

45

During the initial gauge R & R, three sources of measurement related

variation were identified: (1) variation caused by the amount of pack pressure used to

produce each of the parts (hereafter called change in pack pressure), (2) variation in

how the parts were relocated onto the fixture during each of the three measurement

series (hereafter called fixture locating), and (3) variation due to change in the X-axis

value or the variation measured as the CMM probe traveled along the X-axis between

each measurement point (hereafter called change in X-axis values). The variation

along the X-axis was also determined to result from two major sources, including:

(1) variation due to the curvature of the part, and (2) variation due to part surface

irregularities such as texture and sink marks. Based upon results from this initial

gauge R & R, the research team explored opportunities to reduce the contribution of

variation due to part curvature and part relocating within the measurement fixture.

This included the use of regression analysis. A detailed discussion of this approach is

presented in the Analysis of Data section of this chapter.

Full-Scale Visual Evaluation of Sink Marks on Non-Painted Parts

Once the visual evaluation pilot tests were completed and all sink marks

quantified, full-scale visual evaluation study was conducted. The study consisted

involved seven different aspects: (1) visual evaluation methodology, (2) test

population sample size, (3) selecting the observers, (4) visual evaluation of non

painted GDO doors, (5) production of painted GDO doors, (6) visual evaluation of

painted GDO doors, and (7) CMM measurement of painted GDO doors.

46

Visual Evaluation Methodolo&y

During the full-scale visual evaluation study, observers were initially

presented fourteen non-painted GDO doors with various levels of sink marks. These

fourteen parts were produced at pack pressures of: 2350 psi, 2200 psi, 2050 psi, 1900

psi, 1750 psi, 1500 psi, 1350 psi, 1200 psi, 900 psi, 600 psi, 500 psi, 400 psi, 300 psi,

and 150 psi. A follow-up study was conducted using the same fourteen parts with

paint on them to eliminate a nuisance variable detected during the study with non

painted parts. In both studies, each observer completed a series of steps designed to

maintain consistency throughout the study.

Each observer was read the research script explaining the visual evaluation

study (Appendix C). An opportunity was given for observers to ask any questions

about the visual evaluation study. It was explained they could contact the Human

Subjects Review Board at Western Michigan University or the Principal Investigator

if they had further questions that were unable to be answered by the researcher.

Observers then read and filled out the research questionnaire, partially shown

in Figure 19. The questionnaire requested basic information such as eyesight status

(e.g., glasses, contacts, etc.), educational backgrounds and age (Appendix C).

The Effron visual acuity test was then given to each observer (Appendix A).

Observers were instructed to stand at a distance of twenty feet from the visual acuity

chart. In separate test, observers were instructed to cover one eye, look at the acuity

47

4. Do you -wear co rrective lenses? (circle one) yes, no

5. If" yes to #4, do you -wear contacts, KJasses or both? (circle one) contacts, Kl.asses, both

6. If" yes to #4, -what corrective lenses do you -wear at-work? (circle one) contacts, passes, both

7. If" yes to #4, -w-hat corrective lenses do you -wear at home? (circle one) contacts, & l asses, both

8. If" yes to #4, are you near-si&hted or far-si&hted? (circle one) near

si&hted, far-si&hted

9. Do you have color blindness? (circle one) yes, no

Figure 19. Section of Research Questionnaire.

chart, and read the lowest line of letters they could. This step was repeated for each

eye. Results were notated on the lower part of the research questionnaire.

The GDO doors were evaluated using a certified Macbeth SpectraLight II

lighting system. The system was color-balanced using four selectable light sources:

(1) simulated daylight, (2) cool white fluorescent (office or store lighting), (3) horizon

sunlight (simulating early morning sunrise or afternoon sunset), and (4) illuminant A

(incandescent home lighting). The simulated daylight setting was used because it was

recommended by the International Commission on Illumination for visual appraisal of

colors (ASTM, 1996). Observers evaluated the specimens while in a vertical stand up

position. The distance between specimen and observer varied depending on the

height of each observer. The SpectraLight H's four light sources are only 31 inches

+/- two inches away from the observation table.

48

In the MacBeth SpectraLight light booth with a daylight setting, observers

were presented a total of fourteen parts (or treatments) in non-random order, one at a

time. In the non-random sequence, the observers initially did not know where the

sink marks would occur (moving from parts with no sink to parts with the most sink).

Some parts had obvious sink marks that could easily be seen. Other parts were less

conspicuous. Observers were allowed to hold each part in their hands and view it at

any angle. They could not touch the surface of the part with their fingers. Each

observer was given approximately one minute to view each part and notate his or her

response on the sheet provided.

The non-random sequence was used to measure discrimination levels for each

observer and consisted of presenting parts in decreasing order of pack pressure

starting with the highest level of 2350 psi (i.e. least apparent sink marks) and

finishing with the lowest level of 150 psi (i.e. most apparent sink marks). A

randomized order would have sensitized the observers to the sink marks located on

each part, possibly leading to false positives. If observers saw what the sink marks

looked like before testing, they may have tried to read too much into the testing and

say they saw sink marks that were actually not visible on the part.

Test Population Sample Size

A determination of the total number of people required for the evaluation of

sink marks was based upon standard statistical methods (Steel and Torrie, 1980). The

formula for calculating the number of observations per sample was:

49

r � 2( Za12 + Zp)2 ( cr/0)2

Where: "r" represented the number of observations required. a/2 represented type I

error rate for a two-tailed test. The p represented type II error rate. cr represented the

standard deviation of the system. o represented the magnitude of the difference to be

detected. Given these definitions, Za12 was 1.96 for an a of 0.05 and Zp was .84 for

a P of 0.2. The desired difference to be detected in the system was one quarter the

size of the standard deviation. Using this formula, a total number of observers was

determined. To detect a difference one quarter the size of the standard deviation of

the measurement method, a sample population size of no less than sixty observers

was required. Since o was unknown before the study, the o of .25cr was chosen in an

attempt to maximize sensitivity.

Selection of Observers

Ninety-three observers were randomly selected for inclusion in the visual

evaluation study. The test population included observers with and without experience

in the plastics industry. Observers were selected from the following categories:

(a) consumers, (b) assembly operators, (c) molding operators, (d) engineers,

( e) technicians, ( f) managers, (g) team leaders, (h) maintenance personnel, and

(i) production trainers. Approximately a week after initial communication,

appointments were scheduled with those observers willing to participate in the visual

50

evaluation study. No observer who volunteered to participate in the study was

excluded because of age, experience, educational or eyesight status.

All observers signed a consent form before they participated in the study. The

protocol for this study was approved by the Human Subjects Institutional Review

Board (HSIRB) at Western Michigan University (Appendix C). The main role of the

HSIRB is to protect the rights and welfare of human research participants (Western

Michigan University, 1996).

Production of Painted GDO Doors

During the visual evaluation pilot tests, it was discovered that some observers

may have confused sink marks with another defect called witness lines. This issue

was also seen during the full-scale visual evaluation study using non-painted parts.

Based upon preliminary observations from the pilot and full-scale studies, it was

determined that an additional treatment of paint applied to the GDO doors was

needed to mask over the witness line defect. The goal of masking the defect was to

prevent observers from confusing it with sink marks. Below is an overview of the

type of paint used on the GDO doors and how the additional painted parts were

produced.

The identical fourteen GDO doors used during the non-painted parts study

were painted for inclusion in the visual evaluation study of painted parts. To prepare

the parts for painting, they were cleaned with isopropyl alcohol. The parts were then

placed onto a paint rack used in normal production operations. The GDO doors were

51

then spray coated with a water base, Chrysler approved production paint. The paint

was black in color with a four-gloss level. All painted parts were stored using the

methodology described above in the section Product Labeling and Packaging.

Full-Scale Visual Evaluation of Sink Marks on Painted Parts

A follow-up visual evaluation study was completed using fourteen painted

parts. This study was completed using the same methodology as described above in

the section Full-Scale Visual Evaluation of Sink Marks on Non-Painted Parts. The

main difference of the painted part study compared to the non-painted part study was

the addition of paint as a treatment. Another difference between the two studies was

the number of observers. During the non-painted part study over sixty-eight

observers were used to visually evaluate the GDO doors and identify the sink mark

treatments. Thirty-three observers were used during the painted part study.

Quantification of Sink Marks on Painted Parts

CMM surface scans were not conducted on the painted parts until completion

of the visual evaluation. It was determined the CMM probe would leave visible

marks on the painted surface of the GDO doors as each measurement was taken. By

completing the measurements after the visual evaluation was completed, it prevented

observers from seeing the probe marks on the surface of the painted parts. All surface

scans completed on the painted parts were conducted using the methodology

explained above in the section titled Coordinate Measurement Machine Studies.

52

Analysis of Data

Data analysis was categorized into two main components: (1) analysis of

CMM measurement data, and (2) analysis of visual evaluation data. The details of

the methodology used to analyze each of the components are presented below.

Analysis of CMM Measurement Data

Data from each of the surface scans completed during CMM measurements

were analyzed using the statistical software package STATISTICA ® (StatSoft, Inc.,

1996). STATISTICA ® is an extensive software package that offers a variety of

methods for statistical analysis. The X, Y and Z-axis values from the CMM could not

be directly imported into STATISTICA ®. These data had to be translated into the

proper format for STATISTICA ® using two different software packages. The

original CMM data was downloaded into files ( one file for each part measured) using

AutoCAD® software (AutoDesk, Inc., 1993). AutoCAD® is a computer-aided design

(CAD) software used to generate two-dimensional drawings and. three-dimensional

models. The AutoCAD® files were then translated into CATIA ® so that a text files

could be created for each part consisting of the X, Y and Z-axis values (Dassault

Systemes, 1996). CATIA ® software includes CAD, computer-aided manufacturing

and engineering capabilities. Once the data was imported into CATIA ®, the X, Y and

Z-axis values were translated into text files ( one text file for each part measured).

These text files were then imported into ST A TIS TICA® software for final analysis.

53

Initially each scan was displayed on a two-dimensional line plot graph to

verify that no data errors were present. The profile of each surface scan was curved

reflecting the contour of the part. After viewing the data, a multi step procedure was

used to calculate various statistical output values. These steps are presented below:

Using STATISTICA ®, two separate CMM data files were created to store the

X and Z-axis values (CMM data for all parts produced by different pack pressures)

for painted and non-painted parts. The Y-axis was held constant during CMM

measurements. Therefore, Y-axis values were not needed to compute the following

statistical values. These data files consisted of separate columns for the X and Z-axis

values (for each pack pressure, e.g. X50, Z50, ... Xl000, ZlO00, ... ). These CMM

data files were used as the source to compute the following statistical values.

Using standard least squares regression techniques, each of the forty surface

scans were fitted with a second order polynomial regression line (Figure 20). There

were two reasons for fitting the surface scan data to the regression line: (1) eliminate

a nesting problem experienced during the CMM measurements, and (2) remove the

nuisance variable of variation due to curvature designed into the part. During the

gauge R & R, the 100-psi pack pressure part was measured three different times.

Figure 21 shows that surface scans for each of the three measurement series did not

line up directly on top of each other. This variation was caused each time the part

was relocated into the CMM measurement fixture. In order to eliminate this

variation, the statistical software was used to fit a second order polynomial regression

line and to calculate residual values ( distance from each surface scan data point to the

54

1.0 I

0.8 .t...,., Surface Scan �

6 0.6

E 0.4�

.8

� 0.2E 0.0

-� i..,i;; ..... I '

� •

� LI _,... J n, I V �

n. I I V

� Second Order Polynomial Regression Line

-0.20 50 100 150 200 250 300 350 400 450 500

25 75 125 175 225 275 325 375 425 475 525

Scan Point Number

Pack Pressure = I 00 psi

Figure 20. Surface Scan and Regression Line.

1.0

_,. , ... 0.8

,-... 0.6

s (I.)

s ;:I

';;'� 0.4

.8 "' "' -�(I.) �

.. .. -·, ,,._

�

� � ri; ·" if � .

.. �-. , .. . .

j I � �

1:.

( ,.U

""

�- y•

\ . --y

.

"

' . . . 0.2

sI

..... I

V

, ..0.0 l

;

-0.2

0 50 100 150 200 250 300 350 400 450 500

Scan Point Number

Pack Pressure = 100 psi

Figure 21. Overlaid Surface Scans Based Upon Z-axis Values.

Series 1

Series 2

Series 3

55

I I - - 7 I _L

... r---,i-,c -------- ::.-... ---. -- ' Ir- h _ .,,

.....,, L-- '"~ " t ,_ "'

0 -

i5 :'l

-

--•-

•

• • I

!I - IA- l----lliJ4+-+-++-t+ttttrn· A

N

1,

regression line). If the surface scan point was located above the regression line, the

residual was a positive value. If the surface scan point was located below the

regression line, the residual was a negative number. The surface scans based upon

the residual values for all three measurement series (100-psi pack pressure part) are

presented in Figure 22.

1.0

0.8

0.0

-0.2

....... .... � ; ,/''

•,T "' � 1W,'\. "- - � .,. I � I .. r V V ·�·,

,., ...

.,..

0 50 100 150 200 250 300 350 400 450 500

Scan Point Number


Figure 22. Overlaid Surface Scans Based Upon Residual Values.

Series 1

Series 2

Series 3

Data files were created to store the predicted and residual values for each the

forty surface scans. These data files were modified. Four new columns with

corresponding data were added to each file: (1) the X-axis values from the CMM

data file, (2) the Z-axis values from the CMM data file, (3) the absolute values of the

residuals, and (4) a count column to number the data points.

56

Dim

ensi

on (m

m)

Res

idua

l Val

ue

1'.. j...

0 iv

0 °'

The residual values in the sink data files were used to generate two

dimensional line plot graphs. These graphs were used to evaluate the width of each

of the five sink mark areas. After examination of scans across the range of parts, the

boundary of each sink mark area was determined. The boundary points were

generally apparent at the point where the slope of the line rapidly changed in the

transition from the sink area to the "flats" between the sinks areas. A standard width

for each sink mark area was used for all of the forty surface scans.

Once the boundaries were established for each of the five sink areas, a group

column was created in each of the sink data files (for each pack pressure). This

column was used to specify where sink areas one through five began and ended in the

data set. For example, the number one was entered into the group column for all data

points included in sink area #1. Numbers two through five were used for the

corresponding sink areas two through five. The number zero was entered into the

group column to specify which data points were not included in any of sink areas one

through five. The group column was used to identify the data for each of the five sink

areas when conducting statistical analysis.

For each of the five sink mark areas (on all surface scans), a number of

different statistics (range, minimum value, maximum value and total sum variation)

were calculated to explore which one would be the best indicator for quantifying sink

marks. For each surface scan (and sink mark area), the range, minimum value and

maximum value were calculated from the residual value data. The range for each of

the five sink mark areas (using the surface scan points located within the boundary

57

points established in step four) was calculated by subtracting the lowest residual value

(minimum value) from the highest residual value (maximum value). The total sum

variation was calculated by summing the absolute values of the residuals.

All of the statistical values and visual evaluation data were then merged into

one database so that additional statistical analyses could be completed on the

complete set of pressure data. Scatter plot diagrams were generated showing the

visual data (proportion who saw sink marks) on the Y-axis and each of the statistical

values (range, minimum value, maximum value and total sum variation) on the X

axis. Based upon visual analysis of these scatter plot diagrams, a determination was

made that the range value had the best correlation to the visual evaluation data. The

range value was considered an indicator of the depth of each sink mark area. The

nomenclature describing the range is referred to as depth or depth value throughout

the remainder of this thesis.

Analysis of Visual Evaluation Data

Analysis of the visual evaluation data was categorized into two areas: (1) data

from pilot tests, and (2) data from full-scale visual evaluation studies (non-painted

and painted parts).

Analysis of Data from Pilot Tests. During the pilot tests, a research

questionnaire was used to gather basic information about each observer. The primary

purpose of using the questionnaire during the pilot tests was to evaluate observer

58

responses to the questions. This helped to determine whether some questions needed

to be reworded, so they would be clearly understood by all observers.

The primary data gathered during the pilot tests were observer responses

(yes/no) as to whether they could see sink marks on any of the GDO doors presented

to them. These data were evaluated using summary tables. These tables provided a

measure of the consistency of each observer's responses for each part evaluated.

Analysis of Data From Full-Scale Visual Evaluation Studies. For the data

from the visual evaluation pilot studies, a number of summary statistics describing the

test population were generated and presented in tabular format. Information such as

age, eyesight status, occupation, and number of years working in the plastics industry

was gathered from observers using a research questionnaire (Appendix C). The

questionnaire was a modified version of the one used during the visual evaluation

pilot studies.

As in the pilot tests, the primary data gathered during the full-scale visual

evaluation studies were observer responses (yes/no) as to whether they could see sink

marks on any of the GDO doors presented to them. These data were evaluated using

the same type of summary tables that were used in the pilot tests. The only difference

was the addition of three more GDO doors (for a total of fourteen) in the column

designated for pack pressure.

During the full-scale visual evaluation studies, the relationship between the

visual data and CMM data were also analyzed using various scatterplot graphs.

59

Within these graphs, distance-weighted least squares analysis was used to help

evaluate trends in the data.

Summary of the Methodology

The methodology used during this study consisted of a objective measurement

phase and a visual evaluation phase. In the first phase, plastic parts with various

levels of sink marks or treatment values were systematically produced on an injection

molding machine. Measurement scans were completed on the surface of each part

using a CMM. Data from these surface scans were analyzed using statistical software

in order to quantify the depth of each sink mark area present on all GDO doors. In

the second phase, some of these parts were used to conduct two visual evaluation

pilot tests to determine the optimal test method for presenting parts to observers.

During the visual evaluation study, observers evaluated fourteen non-painted GDO

doors to determine whether they could visually perceive sink marks. A follow up

study using painted parts was conducted in order eliminate a nuisance variable

detected during the initial study. The results of the methodology described in this

chapter are presented in Chapter IV.

60

CHAPTER IV

EXPERIMENT AL RESULTS

Introduction

The results of the sink mark quantification and visual evaluation studies are

presented in this chapter. These results are based upon the methodology discussed in

Chapter III.

Sink Mark Quantification Results

The next two sections present the results of the CMM measurement studies

and gauge R & R studies. Three separate measurement series were conducted on a

CMM to gather X, Y and Z-axis values. These data values were analyzed in

statistical software to quantify each of the five sink mark areas. Results from the

gauge R & R studies helped to determine the repeatability of the measurement system

used to measure the GDO doors on the CMM.

CMM Measurement Results

Using a CMM, the goal of quantifying sink marks was achieved. Three

different measurement series were conducted before a quantified value for each sink

61

mark could be obtained. Some difficulties, explained below, arose during the first

and second measurement series. It was not until the third measurement series that

accurate depth values could be calculated for each sink mark evaluated in the study.

The third measurement series depth value results for all five sink mark areas

on the fourteen painted parts are presented below in Figure 23. The first observation

from the line plot graph is that on the part produced at a pack pressure of 150 psi,

Sink 2 is the deepest sink with a depth value of .220 mm. The next deepest sink mark

is Sink 3 with a depth value of .209 mm followed by Sink 4 (.155 mm), Sink 1 (.146

mm) and Sink 5 (.129 mm). The range between the deepest sink mark (Sink 2) on the

part produced with 150 psi and the shallowest (Sink 5) is .091 mm. This range of

.091 mm on the part produced with 150 psi is much greater than the range between

the deepest and shallowest sink marks on the part produced with a pack pressure of

2200 psi (depth value of .005 mm). Another observation from the line plot graph is

the shallowest sink mark measured on any of the fourteen parts is Sink 5 on the part

produced with a pack pressure of 2350 psi (depth value of .029 mm). These depth

value results were used in conjunction with the visual evaluation results to help

determine if a depth value could be identified below which none of the observers

could visually see sink marks.

Before depth values could be calculated, results from CMM surface scans had

to be compiled. During the third measurement series, surface scans consisting of 497

measurements were conducted on thirty-six parts with various levels of sink marks.

62

0.24

0.22

0.20

0.18

i0.16

0.14 0

0.12

0.10

0.08 0

0.06

0.04

0.02

0.00

- � � \ -o-- Sink 1

L--L--

I I\ -o- Sink 2 L--L--

� � I \ -o- Sink3 L--L--

-1,- Sink4 � � L--L--

A. I I 0... L'\--._ I -- Sink5

� �

f \--- I 1\\1

\'

�o. ' ��

r---::: ..... -....__'----

�

-

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400

Pack Pressure (psi)

Figure 23. Painted Part Depth Values for Sink Mark Areas 1-5 (Third Measurement

Series).

Along the axis of the surface scan on each part, there were five potential areas for sink

marks to develop (Figure 12). Figure 24 presents the surface scan profile from the

third measurement series for the part produced with 200 psi of pack pressure. All

surface scans from the third measurement series are shown in Appendix D.

First and Second Measurement Series Results

During the first measurement series, thirty-six non-painted parts with various

levels of sink marks were included. A surface scan consisting of 200 measurements

63

-f--

- u - -

I\

....

--

- ' -

e e

= 0 ·-

= QJ

e·-

..... LO .....

.....

C") LO .....

..- O> r,,... LO 0) "' (0 0 ..... "' "' C")

Scan Point Number

.....

c:o C")

Figure 24. Surface Scan Profile for Pack Pressure of200 psi From Third

Measurement Series.

was conducted on each part. Surface scans from the first measurement series are

shown in Appendix E.

One problem encountered during the first measurement series of parts

involved variation in the interval ( or distance) between measurements. The surface

scans started with an interval of .5000 mm until the probe reached the first sink area

(Figure 12). The sampling interval was then reduced to .2000 mm in the sink area.

After passing through the first sink area, the interval was then changed back to .5000

mm until the second sink area was reached. In the surface areas between sink areas

#1 and #2 and between #4 and #5, an interval of .5000 mm was used. Finally, the

surface areas between sink mark areas #2 and #3 and between #3 and #4 were

measured with an interval of 3.0000 mm in order to reduce total measurement time.

64

39

77

343

419

457

495

533

D

I 0 0

01

0 0

0 0

0 0

0

s (

) 0

.......

.......

01

0 01

0

0 0

0 0

0 0

0 0

All of the five sink areas were measured with a .2000 mm interval. The origin was

the same for each surface scan. The problem is that interval changes were not made

consistently at the same measurement points for all thirty-six scans. The only way

comparisons could be made between surface scans of all thirty-six parts was to use

statistical software to align the data points between the surface scans. Re-measuring

the parts was determined to be a better solution to the problem. Therefore, data from

the first measurement of parts were not used to draw final conclusions.

Given the issues with the first set of measures, a second set of measurements

was conducted on the non-painted parts using a uniform sampling interval across the

entire length of the surface scan. This set also included the four additional parts

produced at pack pressures of 1900 psi, 2050 psi, 2200 psi and 2350 psi. During the

second measurement series, surface scans consisting of 497 measurements at a

uniform interval of .2000 mm were completed on all forty non-painted parts. Surface

scans for all parts measured during the second measurement series are shown in

Appendix F.

A problem with the gauge fixture was also encountered during the second

measurement series. The fixture was disassembled after the first measurement series.

The fixture was later reassembled for the second measurement series. When surface

scans from the second series were compared with scans from the first series, it was

apparent the X-axis had moved. For example, the measurement for sink area #3 was

much deeper in the first measurement series than in the second (Figure 25). Based on

65

these observations, the third measurement of parts was conducted using a dedicated

gauge fixture with no disassembly.

0.15

0.10

0.05

,....._ 0.00 e e = -0.05.s=

-0.10i5

·"

� I � l

� , ..... 'J •�. ., · . .. . ...

r, -r::-: :- ,: .... 1

�ifrf :-�. . _:,,..,._ . ·: ·::,�.:-::1�

-. ·".'-\, ·.�.t�. ..

, • [1!"1,'

.. . �,:_. ' '·· . . ··: \ :'::i. ::·:·. f• •· r. . \ • E

1 ••1� WMr

� �'"-rf.

J 1 ;J

\ r�:{ ' •

:�} I

\1 :v.... .,. " .. ,,, .. -0.15

-0.20 IJf\ Sink deeper on Second I First Series . IV

1= Series than the First Series Second Series -0.25

0 50 100 150 200 250 300 350 400 450 500 Scan Point Number

Figure 25. Surface Scan Comparison Between First and Second Measurement Series

for Part Produced With Pack Pressure of 100 psi.

Gauge R & R Results

To investigate and quantify the CMM measurement precision, a gauge R & R

was executed. The study involved the Z-axis values. A second gauge R & R was

conducted based on the residual values from the regression analysis (see Chapter 111).

The regression analysis was completed to eliminate two nuisance variables: (1)

variation due to successive relocation of parts onto the fixture during CMM

66

.,, "' e

I.-

f

-

..... -~ I- I -

I r I 1

~ ···

[ J

1 1 I I

- I. l . . , . r f

I I I l lf

l ,__

I

. _ l I ..

- r-, .

·1 l ·1 I

- - - · - ...........

-~

I 1 I I .· I

I I I -

-I -~ - =-

measurements, and (2) variation due to the curvature designed into the profile of the

GDO door.

The results of the gauge R & R based upon the Z-axis values are presented in

Table 1. The largest variation in the Z-axis values during measurements was due to

change in the X-axis values. This accounted for 99.5% (estimated variance = .0452)

of the total variation observed in the measurement system. This variation was due to

several factors: (a) curvature of the part, (b) texture variation, and (c) the five sink

mark areas. The second largest source of variation was due to the change in pack

pressure treatment (100 psi, 1000 psi, and 1900 psi). This accounted for 0.5%

(estimated variance = .0002) of the total variation observed in the measurement

system. The third source of variation isolated in the analysis was attributed to

locating each part onto the fixture during CMM measurements (Figure 18). This

accounted for 0.2% (estimated variance = .0001) of the total variation within the

measurement system. Compared to the total variation within the measurement

system, the variation attributed to locating each part onto the fixture was relatively

small. The final source of variation, the interaction between the change in pressure

and change due to locating the parts in the fixture, was not a factor (0.0% - based

upon % of Total).

The results of the gauge R & R analysis of the residual values (presented in

Table 2) showed the percent of total values for each of the sources of variation were

similar to those in the gauge R & R based upon the raw Z-axis values. This second

67

Table 1

Results of Gauge R & R Based Upon Z-axis Values

Estimated Estimated ¾ofR&R % of Total Source of Variation Sigma Variance

Change in X Value .212572 .045187 99.4519 99.2050

Change in Pressure (P) .015781 .000249 .5481 .5467

Interaction (PL) 0.000000 0.000000 0.0000 0.0000

Fixture Locating (L) .010634 .000113 .2483

Combined R & R .213157 .045436 100.0000 99.7517

Total .213422 .045549 100.0000

Table 2

Result of Gauge R & R Based Upon Residual Values

Source of Variation Estimated Estimated

¾ofR & R % of Total Sigma Variance

Change in X Value .040526 .001642 99.9771 99.9771

Change in Pressure (P) .000613 .000000 .0229 .0229

Interaction (PL) 0.000000 0.000000 0.0000 0.0000

Fixture Locating (L) 0.000000 0.000000 0.0000

Combined R & R .040531 .001643 100.0000 100.0000

Total .040531 .001643 100.0000

gauge R & R analysis confirmed that variation due to locating the parts into the

fixture and due to the curvature in the profile of the part was reduced. This was

68

determined by comparing the estimated sigma and estimated variance values from the

raw Z-axis value analysis with the same statistics from the residual value analysis.

The estimated variance for the combined R & R was .0454 using the Z-axis values

compared to .0016 using the residual values. This was a 90.4% overall reduction in

the estimated variance. The estimated sigma for the combined R & R was .2132

using the Z-axis values and .0405 using the residual values. This was an 80.9%

overall reduction in the estimated sigma. Graphs of the surface scans for the Z-axis

values and residual values are presented in Appendix G.

Reduction in measurement related variation using residual values rather than

raw Z-axis values can be seen by comparing their respective plots of the average

measurements by pack pressures for each of the three measurement series. As an

example, the range in average raw Z-axis measurements of the 100 psi treatment

(Figure 26) was .071 mm. The range in average residual values (Figure 27) was 1.3 x

10·9 mm. Using the residual values rather than the Z-axis values represents a 99.9%

reduction in variation based upon the difference between the range for Z-axis values

(.071 mm) and range for residual values (1.3 x 10·9 mm).

Visual Evaluation Results

Visual evaluation results were acquired from two series of testing: (1) visual

evaluation of painted parts, and (2) visual evaluation of non-painted parts. Results

from the painted parts study are presented first followed by the results of the non-

69

0.75

0.70

0.65

0.60

0.55

0.50 0

0.45 0

0.40

0.35 0

0.30 0

0.25

0 0.20

0.15

0.10

0.05

0.00

-►··'· !. �. �- �- : •.... • .... _. _ _._ .• .. : .: ..... ·491'· -�

2 Measurement Series

3

Figure 26. Average Measurements Based Upon Z-axis Values.

0.75 �--�-------�------�--� 0. 70 f------+-------+---------+----10.65 t------+-------+--------+-----1

0.60 1-----+---------+-------,1-----1

0.55 >------+--------+--------+------<

0.50 f------+-------+---------+----1 0.45 f------+-------+---------+----1 0.40 f------+-------+---------+----1 0.35 >------+-------+--------+------<

0.30 t------+--------+--------+------<

� 0.25 f------+-------+---------+----1 ] 0.20 ....., 0.15 f------+-------+---------+----1

0.10 t------+-------+--------+-----1

0.05 f------+-------+---------+----1 0.00 1---------------------1-----J

1 2 Measurement Series

3

Figure 27. Average Measurements Based Upon Residual Values.

- 100• 1000

.......... 1900

- 100···•··· 1000.......... 1900

70

e M

easu

rem

ent

Av

rag

M a

sur

m n

t

I

' 1·

painted parts study. Information that defines the test population is also presented

followed by results acquired during the visual evaluation pilot tests.

Test Population Attributes

The test population for the combined non-painted and painted part studies

consisted of a combined total of ninety-three observers. During the studies, the

observers filled out a research questionnaire that provided specific information that

helped define the attributes of the test population. Some of the attributes were basic

information such as age and educational status. Most of the questions on the

questionnaire were focused on the eyesight status of each observer.

In order to give an overview of the attributes of the test population, a series of

tables are presented. Table 3 shows an overview of the age ranges for all the

observers included in the population for the study. The majority of observers

participating in the study were within the age range of26 to 35 years. Over 90% of

the observers were below the age of 45 years.

Eyesight status of the observers is presented in Table 4 and includes visual

acuity for right and left eyes, visual aberrations such as near-sightedness or far

sightedness, and any visual enhancement such as glasses or contacts. The majority of

observers had left and right eye visual acuity's of 20120. Approximately 54% of the

observers wore corrective lenses (contacts, glasses or both at different times) during

working hours. At home, 44% of the observers wore contacts, glasses or both at

71

Table 3

Age Ranges of Observers Included in Visual Evaluation Test Population

Range (years)

18-25

26-35

36-45

46-55

56-65

Number in Range

29

42

14

5

3

different times. Regarding visual aberrations, 47% of the observers were near

sighted, 7% were far-sighted and 39% were neither near nor far-sighted.

An additional question asked on the research questionnaire was how many

years each observer worked within the plastics industry (Table 5). There were nine

observers who had no experience in the industry. The majority of observers had

between one and two years of experience working with plastics.

The final question for the test population included what position of work they

held at the time of the visual testing (Table 6). The majority of observers (35 total)

were operators who worked within the injection molding environment. The next

highest group of observers (22 total) was the assembly operators who assembled the

GDO door into the final assembly. The third highest group of observers (10 total)

consisted of engineers ( e.g. process engineers and quality engineers).

72

Table 4

Overview of Eyesight Status for Observers Included in Test Population

Visual Acuity Visual Aberrations Vision Enhancement

Level Number of Number Number

of Left Right

Type People

Type Who Who

Acuity Eye Eye with Use at Use at

Aberration Home Work

20/13 2 2 Near-sighted 44 Contacts 11 18

20/15 5 7 Far-sighted 7 Glasses 30 28

20/20 29 26 Bi-focal 6 Both 12 4

20/25 26 18 None 36 Neither 40 43

20/30 14 11 Color Blind 4

20/40 8 14 Not Color

89 Blind

20/50 6 12

20/70 2 2

20/100 1 1

Visual Evaluation Pilot Test Results

The following results were acquired from two visual evaluation pilot tests

where observers viewed GDO doors for sink marks. For details of the methodology

used during each test, see Chapter III.

73

74

Table 5

Number of Years Each Observer Worked in Plastics Industry

Number of Years Number of Observers

0 9

1 25

2 20

3 9

4 6

5 2

6-10 15

11-15 6

16-20 1

Table 6

Occupation for Observers Included in Test Population

Occupation Number of

Observers

Molding Operator 35

Assembly Operator 22

Engineer 10

Technician 7

Paint Operator 6

Consumers 4

Team Leader 3

Materials 2

Manager 2

Trainer 1

Maintenance 1

Pilot Test #1

Results of the hand-held testing for observer #1 are shown in Table 7.

Complete results of the hand-held observations are presented in Appendix I. The

first pilot test was conducted using non-painted parts. The Y's represented an

observer responding they could see sink marks. The N's represented an observer

responding they could not see sink marks. Observers #1 and #2 responded

inconsistently on parts produced at pack pressures above 1000-psi. For example,

Table 7 shows how observer #1 began to see a sink mark in area #1 on the part

Table 7

Results From Observer #1 - Hand Held Observation

Pack Press. Sink Area 1 Sink Area 2 Sink Area 3 Sink Area4 Sink Area 5

(psi)

1750 N N N y y

1600 y N N y N

1450 y y N N y

1300 N y N y y

1150 y y y y y

1000 y y N y y

850 y y N y y

700 y y N y y

550 y y y y y

400 y y y y y

250 y y y y y

75

produced at a pack pressure of 1600 psi. The observer also saw the sink in area #1 on

the 1450 psi pack pressure part. When viewing sink area #1 on the 1300 psi pack

pressure part, observer #1 said they did not see the sink mark. Similar responses were

seen for sink mark areas #4 and #5.

Pilot Test #2

Three different methods were used to present non-painted parts to observers

during the second pilot test: (1) 13 inch viewing slot, (2) four inch viewing slot, and

(3) rank order tests. Results from the 13 inch viewing slot (Appendix I) and four inch

viewing slot (Appendix I) tests involved observers viewing part through a cardboard

viewing slot to control the angle of observation. Results from the rank order tests

involved presenting observers parts in groupings of three and eleven. Results are

discussed below.

13-Inch Viewin& Slot Test. During this test, observers were presented eleven

parts in random order and asked to evaluate them for sink marks in five different

areas. A wide width of viewing slot in the cardboard nest allowed each observer to

change the angle of observation when viewing each part. Results of the 13-inch

viewing slot test are presented in Appendix I. Two out of the five observers (40%)

tested said they saw sink marks at the highest pack pressure of 1750 psi. In addition,

four out of the five observers (80%) said they saw sink marks at the second highest

pack pressure of 1650 psi.

76

Four-Inch Viewing Slot Test. During this test, observers were again presented

eleven parts in random order and asked to evaluate them for sink marks in five

different areas. The reduced width of the viewing slot limited each observer's ability

to change the angle of observation when viewing each part. The results of the four

inch viewing slot test are shown in Appendix I. Three observers were tested using the

four-inch viewing slot. Two of the three observers began to see sink marks on the

part produced with a 1300 psi pack pressure, which is 450 psi lower than the point at

which sink was seen in the 13 inch viewing slot test. All three observers had

difficulty seeing the sink marks. This may have been the result of the limited angle of

observation created by the 4" viewing slot.

Rank Order Tests. The third test in the second pilot involved presenting non

painted parts to observers and asking them to rank them in order of preference. Two

different groupings were used when presenting parts to each observer: (1) groupings

of three, and (2) group of eleven.

Groupings of Three. During the rank order test by groupings of three, one

observer ranked correctly one, two & three for all four sets of three parts. Two

observers ranked all sets correctly, except for the group with 1000 psi, 1150 psi and

1450 psi. In this group, the two observers preferred the 1000 psi part over the 1150

psi part. The results of each observer were recorded in Table 8 by ranking order of

77

Table 8

Results From Rank Order Test by Groupings of Three

Order Parts Shown Ranking by Ranking by Ranking by Observer #1 Observer #2 Observer #3

Group 1 1750 1 1 1 850 2 2 2 250 3 3 3

Group 2 1600 1 1 1 550 2 2 2 400 3 3 3

Group 3 1450 1 1 1 1150 2 3 3 1000 3 2 2

Group 4 1750 1 1 1 1300 2 2 2 700 3 3 3

preference (#1 - least visible or no sink marks, #2 - middle preference and #3 - most

visible sink marks).

Group of Eleven. The fourth and final test of the second pilot test was a rank

order test grouping of eleven non-painted parts produced at different pack pressures.

Observers were asked to rank the parts from number one - most preferred (less sink or

no sink) to number 11 - least preferred (most sink). The results of this rank order test

are shown in Table 9.

78

Table 9

Results From Rank Order Test by Grouping of Eleven

Order Parts Ranking by Ranking by Ranking by

Shown Observer #1 Observer#2 Observer #3

1750 psi 1 1 1

1600 psi 2 2 2

1450 psi 7 3 3

1300 psi 3 6 6

1150 psi 5 7 7

1000 psi 6 4 8

850 psi 4 8 4

700 psi 8 5 5

550 psi 9 9 9

400 psi 10 10 10

250 psi 11 11 11

All three of the observers tested, correctly ranked the 1750 psi and 1600 psi as

number one and two, respectively. Two out of the three correctly ranked the 1450 psi

part as number three. Another observation is that observer #1 ranked correctly the

700 psi, 550 psi, 400 psi and 250 psi as numbers eight, nine, ten and eleven

respectively. Observers #2 and #3 ranked parts nine, ten, and eleven correctly. The

observers appeared to be able to rank the sink marks consistently at pack pressures

below 700 psi.

Based upon the results of the second pilot test, it was apparent that sink marks

were visible to at least some observers on all parts. Subsequently, four additional

non-painted parts were manufactured at higher pack pressures (1900 psi, 2050 psi,

79

2200 psi and 2350 psi), in an attempt to further reduce the apparent sink marks.

CMM surface scans were also conducted on these parts. With the addition of these

four pack pressures, the total number of parts with different treatments (levels of sink

marks) used in the visual evaluation study was increased to fourteen.

Visual Evaluation Results - Painted GDO Doors

The visual evaluation results from the painted parts study revealed that a depth

value existed below which no observer could see sink marks. This threshold depth

value or "visual limit" was identified using scatter plot graphs which showed the

proportion of observers who saw sink marks at various depth values. Figure 28

shows the results of the painted parts study for sink mark areas #1, #2, #4 and #5.

Several observations were made based upon these results. First, observers could not

see sink marks below a depth value of .040 mm. Therefore, for these four sink areas,

the depth value of .040 mm was identified as the visual limit of an observer's ability

to see sink marks. Secondly, the visual results showed that all observers were able to

see sink marks with depth values greater than .075 mm. There were nineteen sink

marks observed with depth values greater than .075 mm. Every observer who

participated in the painted parts study detected all nineteen. Another observation was

that each observer's ability to detect sink marks in areas #1, #2, #4 and #5 increased

significantly when viewing areas with depth values greater than .050 mm. This result

suggested that observers were able to detect a distinct change in the visual appearance

80

�

(I)

0

� 0 ·-e0

0

1.0 0.9 0.8 0.7

��a /2 -

I00

oof

0.6 0.5 0.4 0.3 0.2 0.1 0.0

I I /_ u Depth Values below .040 mm �-b

I/ VI

/ bo

./ I 'a.___ Sink Areas 1,2,4,5 I -I ) Vn..,. ... ,.�

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 0.ot 0.03 0.05 0.07 0.09 0.11 0.13 0.15 0.17 0.19 0.21 0.23

Depth Values (mm)

Figure 28. Results of the Painted Parts Study for Sink Areas #1, #2, #4 & #5.

of sink marks at depth values greater than .050 mm. In Figure 28, the visual results

for sink areas #1, #2, #4 and #5 were graphed along the same plot line because the

geometric shapes of the sink marks were almost identical. However, the geometric

shape of sink mark area 3 was substantially different from the other four sink areas.

Therefore, the visual results for sink area 3 were graphed on a separate plot line as

shown in Figure 29. The visual results for sink area #3 also revealed that a depth

value existed below which no observer could see sink marks. Figure 29 shows that

observers could not see sink marks below a depth value of .044 mm. This visual limit

of .044 mm for sink area #3 was .004 mm larger than the visual limit of .040 mm for

sink areas #1, #2, #4 and #5. In addition, visual results for sink area #3 showed that

81

'

Cl)

� u3

0

� t:: 0

'€

0

.. . . ·-.... 1.0

0.9

0.8

0.7

� i� /2 p •'[]

I00 9

oof.u

C

0.6

0.5

0.4

0.3

I 9

I I - �-b

0.2

0.1

0.0

'o..___ f--

I cf· Sink Areas 1,2,4,5

I�

Sink Area 3 f--

7 ••

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 0.01 0.03 0.05 0.07 0.09 0.11 0.13 0.15 0.17 0.19 0.21 0.23

Depth Values (mm)

Figure 29. Results of the Painted Parts Study Comparing Sink Area #3 to Sink Areas

#1, #2, #4 & #5.

all observers were able to see sink marks with depth values greater than .105 mm

which is .030 mm greater than the other four sink areas. These results suggest the

possibility that differences in the geometric shape of a sink area #3, as compared to

the other four sink areas, negatively affected each observer's ability to detect the

defect. For example, at a depth value of .060 mm, only 57.6% of the observers could

detect sink area #3. In comparison, approximately 90% of the observers detected sink

marks with depth values similar to .060 mm in sink areas #1, #2, #4 and #5.

82

0 p. 1J, D

Visual Evaluation Results - Non-Painted GDO Doors

The visual results from the non-painted parts study are presented in Figure 30.

As with the painted parts results, sink areas #1, #2, #4 and #5 are all graphed on one

line plot. Sink area #3 is graphed separately on another line plot because the results

were substantially different from the other four sink areas. Non-painted and painted

parts results are presented together in Appendix H on individual scatter plot graphs

for each of the five sink mark areas.

Vl

] Cl)

Cl)

0

� i:= 0

·-e0

1.0

0.9

0.8

Cl.---' - 0 vv 0 n

0.7

0.6

R'il

I� 0.5

0.4

0.3

0.2

0.1

0.0

/v □ ,u

/, ,· n

/� 0 □•.

r� o·i:Rit

� -◄) - )

0

---□·

'a--.. u

... . . .. • •. • E

Sink Areas 1,2,4,5

Sink Area 3

I

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 0.01 0.03 0.05 0.07 0.09 0.11 0.13 0.15 0.17 0.19 0.21 0.23

Depth Values (mm)

Figure 30. Results of the Non-Painted Parts Study Comparing Sink Area #3 to Sink Areas #1, #2, #4 & #5.

Two results from the non-painted parts study were distinctly different when

compared to results from painted parts. First, there were no depth values identified

83

Prop

aw

M

ark

_ ___

_,,,,

--

·hx

,, l-

--+

---1

1--

-'tl

-.l-

-l--

-+--

·-:::

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-

C 0

.

,_

--

l+--

-ll-

--'-

+--

--1

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-,_

--

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--

--

below which observers could not see sink marks. To illustrate, the results in Figure

30 showed that even at the lowest depth value of .029 mm, 11.9% of the observers

said they could detect the sink mark. This result supported the possibility that

observers confused sink marks with another surface defect called witness lines. In

addition, a visual limit for sink marks could not be established based upon results

from the painted parts study. Secondly, all of the observers said they were able to see

the sink mark at a depth value of .115 mm. However, after detecting the sink mark

with a depth value of .115 mm, observers were inconsistent in detecting other sink

marks at depth values greater than .115 mm. To clarify, there were seven sink marks

with depth values greater than the .115 mm. Of those seven sink marks, all observers

could not see three.

One result similar to the painted parts study was the significant increase in

each observer's ability to detect sink marks at depth values greater than .050 mm

(sink areas #1, #2, #4 and #5). Another similarity with the painted parts study is the

significantly lower proportion of observers who saw a sink marks in area #3 as

compared to the other four sink areas at depth values greater than .045 mm.

Summary of Results

Results were presented from a series of studies involving three CMM

measurement studies, one visual evaluation study, and two visual evaluation pilot

tests. Results from the pilot tests helped to develop the methodology used during the

84

visual evaluation study. The CMM studies produced results where the depth of each

sink mark area was quantified. The depth values were used in conjunction with the

results of the visual evaluation study to determine the depth level of sink marks below

which no observers could see the defect. Results from the guage R & R study showed

that data based upon residual values considerably reduced variation within the

measurement system. The initial study during visual evaluation was conducted using

non-painted parts. During the study it was discovered that observers may have

confused another surface defect, witness lines, with sink marks. A follow-up study

was conducted using painted parts to mask over the witness lines. The results from

the painted parts study showed there was a depth level of sink marks on the GDO

doorts below which no observers could see sink marks. The visual studies also

illustrated the difficulty of acquiring reproducible repsonses between observers when

relying on subjective visual analysis.

85

CHAPTERV

CONCLUSIONS AND RECOMMENDATIONS

Conclusions

The two main purposes of this thesis work were to determine if sink marks

could be objectively quantified and to determine ifthere was a level at which all

observers in the study were not able to see the sink marks.

Based upon the results of the coordinate measurement machine studies it was

concluded that sink marks could be objectively quantified. Quantifying sink marks

was achieved using statistical software to analyze CMM surface scan data for each

sink mark area evaluated. This methodology confirms that the attribute can be

objectively measured. Every part used in this study had measurable sink marks.

Based upon the comparison of results between the CMM and visual

evaluation studies (painted parts), a depth value of .040 mm was identified below

which no observers could see sink marks on any of the areas evaluated. This means

that for the part used in the study, sink marks do not have to be completely

eliminated. Furthermore, it may be possible to replace the subjective measurement

currently used to evaluate the GDO doors with the methodology developed in this

thesis.

86

Conclusions From the CMM Studies

In order for the CMM data to be reliable, it was concluded that major sources

of abnormal variation within the measurement system had to be reduced. Major

sources of variation were reduced in order to obtain accurate depth values for each

sink mark area. The curvature of the GDO door, part surface irregularities (texturing)

and relocation of the GDO doors into the measurement fixture caused the major

sources of measurement variation.

To address CMM surface scan variation, it was determined that a

programmable measurement set-up was required. The following issues had to be

addressed when the programmable set-up was developed:

1. A consistent point of origin had to be established for each surface scan that

was performed using a CMM. Without a consistent point of origin, data from one

surface scan could not be compared with data from another surface scan. By

establishing the programmable measurement set-up, a consistent point of origin was

maintained for each surface scan completed.

2. A consistent distance between each measurement point had to be

maintained when measuring every part used in the study. Ideally, the interval should

be held constant between all measurement points within a surface scan. If the interval

must be changed to reduce the time required to complete each surface scan, the exact

location of the interval change must be programmed into the CCM so it can be

repeated for all additional surface scans within a study.

87

3. A gauge R & R had to be completed to assess the repeatability of the CMM

when measuring all data points within each surface scan. Assessment of

reproducibility was necessary to determine the ability of the CMM to duplicate the

same surface scan measurements on all parts used in the study. After all major

sources of variation within the measurement system (discussed below) were

addressed, the gauge R & R verified the CMM was capable of completing a

repeatable surface scan on each of the parts used in the study. To address variation

due to the measurement fixture, it was concluded that a dedicated fixture should be

used throughout the study.

4. There could be no disassembling of the fixture between measurement

senes. Each time the fixture was reassembled, surface scans from the previous

measurement series could not be duplicated. Only when the fixture was dedicated

could repeatable surface scans be completed.

5. The curved contour of the GDO door made it difficult to nest it repeatedly

in the measurement fixture. Initial attempts to improve repeatability by modifying

the measurement fixture were unsuccessful. The variation caused by the contoured

surface of the GDO door could not be physically altered. Therefore it became

necessary to correct for this variation mathematically using least squares regression

techniques. Based upon the gauge R & R, the CMM data corrected in the manner

were determined to be reliable.

88

Conclusions From Visual Evaluation Studies

The following conclusions are based upon the data related to sink mark areas

1, 2, 4 and 5. The correlation between the CMM and visual evaluation data for the

painted parts used in this study revealed there were three distinct groupings of data.

The first group of data consisted of the depth values greater than .075 mm, where all

observers were able to see the sink marks. The second group of data consisted of the

depth values less than .040 mm, where all observers were not able to see sink marks.

The third group of data consisted of depth values between .041 and .074 mm, where

observers were inconsistent in their ability to detect the sink marks. These data

suggested the correlation between the CMM and visual evaluation data was decidedly

non-linear. This was evidenced by a depth value threshold below which no observers

could see sink marks.

Because no observer could see sink marks below this threshold, the possibility

exists that a standard could be established for acceptable levels of sink marks on the

part used in this study. There was another depth level threshold above which all

observers could see sink marks. This suggested that at higher depth levels, visual

measurement was a viable option for sink mark detection. However, there was

considerable variation in the ability of different observers to see sink marks with

depth values that fell in between the two thresholds stated above. This is the type of

variation in visual measurement that can lead to acceptable parts being rejected or

89

visa versa. These inconsistencies underscore the need to improve visual measurement

by developing objective measurement methodology for attribute defects.

In addition to the conclusions already discussed from the visual evaluation

studies, it was concluded that painting the parts appeared to be effective in masking

over the witness lines and other surface flaws. This eliminated the possibility of

observers confusing them with sink marks and enabled them to more clearly

distinguish the sink marks than when evaluating non-painted parts.

During the study using non-painted parts, some observers said they could see

the sink marks on every part presented. These results suggested the possibility that

some observers confused sink marks with another defect called witness lines. The

difficulty of trying to determine whether observers actually saw sink marks at the

lower depth values made it impossible to determine if a level existed at which all

observers were unable to see sink marks for non-painted parts.

Recommendations

Below are several recommendations based on the results and conclusions of

this thesis. These recommendations are divided into expansion of the work in this

thesis study, and implementation of this study in a manufacturing environment.

ExPansion of This Study

There are at least three areas into which further study is recommended: (1)

expansion of the acceptance standard developed for sink marks, (2) investigation into

90

the effects of different materials on sink mark formation, and (3) application of the

methodologies in this study to other attribute defects.

Additional studies should be conducted to determine if a standard depth level

for non-visible sink marks could be established for all plastic parts. The study could

be completed using one plastic resin for all parts studied to minimize the number of

variables. Selecting different sizes of products with various design features and

surface textures would help in assessing if non-visible sink marks on these parts have

similar depth values. Using the methods developed for this thesis, the different levels

of sink marks on each type of part could be quantified. The quantified sink marks

from each type of part could be grouped based upon similar depth values. Then a

visual evaluation study could be conducted for each part to determine the depth value

at which no observers can see the sink marks. Once depth values for non-visible sink

marks are established for each part used in the study, they would be compared to

determine if they are similar. If the depth values between the different parts were

significantly different, follow-up studies would need to be conducted to determine

what led to the differences.

If a standard depth level for non-visible sink marks can not be established for

all plastic parts, in the study discussed above, additional measurement systems should

be evaluated to determine whether sink marks can be quantified based upon area,

volume or shape. During the thesis work, depth values were calculated based upon a

cross-section of each sink mark. Other measurement systems may have the

capabilities to quantify the entire volume of each sink mark analyzed. If sink marks

91

were quantified based upon volume or area, a stronger correlation than in this study

may exist between the new measurement technique and observers' ability to see

them.

Another study recommended is to evaluate the effect of different materials on

sink mark formation. Changing the material after each injection molding run would

be completed in order to produce the same part consisting of different materials.

Materials could be selected based upon various shrink rates, types of additives and

other material characteristics. During each run of a selected material, the pack

pressure would be systematically manipulated to produce parts with varying depth

values of sink marks. Using the methodology from thesis work, parts would be

measured on a CMM and analyzed with statistical software to calculate depth values

for each sink mark. Depth values of sink marks on the parts consisting of different

materials would be compared for differences. Additional comparisons of data would

include overlaying the surface scans of the various parts produced with different

materials. The results of this type of study would help determine what type of effect

different materials have on sink mark formation.

Finally, various attribute defects such as splay, scratches, marring and other

types of surface defects should be evaluated to determine if they could be quantified

using similar methods to those used in this sink mark study. Other measurement

systems should also be investigated to develop new methods of quantifying different

attribute defects.

92

Implementation in the Manufacturing Environment

The main purpose of implementing the type of methodology conducted in the

thesis was to improve upon subjective visual defect analysis by replacing it with or

using it in conjunction with objective measurement methodology. Using objective

measures for defects that have traditionally been evaluated visually can aid in the

process of establishing clearly defined part acceptance standards with customers.

These objective acceptance standards can then be communicated to operators who

regularly produce the product to avoid any uncertainties. Below are some

recommendations for implementing into the manufacturing environment the

methodology described in this thesis.

Since quantifying sink marks using a CMM can be time consuming,

implementation of this study in a manufacturing environment can best be achieved

through incorporation into a design of experiments. Using the depth value as a

measure of sink marks during a designed experiment would enable a molder to

evaluate a new or existing injection mold to determine if parts can be produced with

an acceptable depth of sink marks. It is recommended this type of study should be

conducted on new or existing injection molds that are considered to have a high

potential for the development of sink marks in visible areas on the part surface. If the

designed experiment helps determine a process set-up of parameters that consistently

produces acceptable levels of sink marks, then process control could be used to

maintain that set-up over time. If the experiment shows the optimized set-up is

93

unable to produce parts with acceptable levels of sink marks, then this could be used

as a justification for changing the part or mold design. Once this study has been

completed on a given mold, a baseline could be agreed upon with the customer as to

what depth value and tolerance for sink marks is acceptable. This depth value could

be integrated into a product control plan and monitored by conducting process control

on the optimized process parameters established through the DOE.

Since the thesis work validated human observers' ability to visually detect

sink marks, it is recommended that a panel of observers be used in conjunction with

the DOE stated above. The variation among viewers it this thesis study suggests it

would be best to use larger numbers of evaluators, probably in a proper DOE. This

panel of observers would be used to evaluate the parts produced from various process

set-ups to help determine an acceptable depth for sink marks on the part produced

during the DOE. It is also recommended that the observers evaluate the parts in a

controlled environment, such as a light booth, to reduce possible nuisance variables.

Once the acceptable depth value for the sink marks has been established, the

observers could be used to detect unacceptable parts during production.

Finally, an injection mold usually goes through a series of preliminary tests

before it is released into production. Typical elements of mold tryouts involve

establishing the initial set-up of process parameters along with visual and dimensional

verification of parts. Sink mark analysis could be incorporated as another element

into mold tryout procedures. During dimensional verification, any sink marks on the

94

surface of the part could be measured to determine if there is a depth value at which

no observers can see the sink marks for use as acceptance criteria.

95

Appendix A

Effron Visual Acuity Wall Chart

96

97

Effron Visual Acuity Wall Chart

1

F p 2

T 0 z 3

L p E D 4

PECFD 5

EDFC2P 6

FELOPZD 7

fJ:E:FFOTEC 8

LCFODP CI" 9

!'DPLI"CCO 1 □

?J:TOLCrT:D 11

Appendix B

Digital Pictures of Fixture Used for Coordinate Measurement Machine

98

99

Digital Pictures of the Fixture Used for CMM Measurements.

100

Appendix C

Proposal and Forms Submitted to the Human Subjects Review Board

at Western Michigan University

101

W estem Michigan University

Human Subjects Institutional Review Board (HSIRB) Proposal for Thesis Experimentation:

Quantifying a Key Injection Molding Attribute Defect

PROJECT DESCRIPTION

102

The purpose of this research is to quantify a key injection molding attribute defect called sink marks. Sink marks are a shallow depression or dimple on the surface of a finished plastic part due to shrinkage or low fill of the mold cavity. Human observers will evaluate a series of injection molded parts that have various levels of sink marks. The project will take place at Prince Corporation in Holland, Michigan. Human observers will view parts under a Macbeth SpectraLight Color viewing booth at the Prince-Maplewood

plant. The duration of the project for each observer will be approximately one half hour.

During the literature review of this thesis, it was determined that depth perception and

visual acuity are two key factors in determining a human observers ability to perceive sink marks. Therefore, during research, human observers will be asked to participate in the Stereo Fly Stereopsis Test and Effron Wall Chart visual acuity test. The stereopsis test is a universally known and understood vision test where human observers view a picture of a fly in booklet form. If the image of the fly is only viewed using one eye, the fly will appear as an ordinary flat photograph. If both eyes are functioning properly, the response

of the observer will be the ability to see the fly in three dimensions. The second test,

visual acuity, will involve asking human observers to view the Effron Wall Chart at a specified distance. They will then be asked to cover one eye and read the smallest line of numbers they are able to see. Then they will be asked to uncover the first eye and then cover up the second eye and repeat the process. If they are able to read the bottom line on the chart, the observer has 20/20 vision.

After completing the depth perception and visual acuity tests, observers will be asked to view a series of plastic parts with various levels of sink marks. The research design to be

used is called the paired comparison procedure. When using this procedure, human observers are given two parts to observe in order to determine which one is preferred. If one part is picked more strongly, then it can be concluded that some of the observers are

able to tell the difference between the two parts. The only discrimination information provided is if one part is strongly preferred. It simply means that observers are able to tell the difference between the two parts. This procedure is not designed for use with more than two parts. This procedure will be repeated for each of ten levels of sink marks.

103

BENEFITS OF RESEARCH

The short-term benefits of this research involve a determination of what level a majority

of observers are able to see sink marks. This level will be quantified in order to reduce

the subjectivity when viewing the defect. This will also translate into long term benefits

by providing a higher confidence level for human observers whose work requires them to visually detect sink marks. The minimum-maximum levels of a defect, such as sink marks, are sometimes changed throughout the life cycle of a plastic part. This fluctuation

may confuse human observers when viewing sink marks, especially when sink marks are at a level that a majority of observers are unable to visually detect.

SUBJECT SELECTION

Subjects will be selected based upon their response to a distributed pamphlet that invites

them to participate in the research. The invitation pamphlet is basically a reduced portion

of the attached consent form. The Principle Investigator's, Student Investigator's, Chair of Human Subjects Institutional Review Board's, and Vice President for Research's

phone numbers will be provided in the pamphlet. Potential subjects will be informed in the pamphlet that they can contact any of these people to ask questions about the research. Once the subjects have verbally agreed to participate in the research, an appointment will be set-up. During this appointment, they will be presented the attached Consent Form and Research Questionnaire. No subjects will participate in the research until they have read, understood and signed the Consent Form. Then subjects will

participate in visual acuity and depth perception tests before visually examining plastic

parts with various levels of sink marks.

RISKS TO SUBJECTS

One potential risk may involve discomfort to the eyes of human observers from viewing a number of plastic parts. Each observer will view ten sets of two, or twenty total plastic parts. Since the evaluation will take place using a universally accepted Macbeth

SpectraLight color booth, the known risks are minimal.

PROTECTION FOR SUBJECTS

Subjects will be informed of the potential for discomfort to their eyes. Prior to the test, they will be informed via the attached Consent Form that they can rest their eyes at

anytime during the evaluation. Most observers working in a plastic's company evaluate

104

parts at the molding press for eight hours. They usually take two breaks and then a lunch period to help provide the rest they need. Since the viewing of parts will only take about

ten minutes, the risk of discomfort to observers' eyes will be minimal.

CONFIDENTIALITY OF DATA

All the information collected during the project will be confidential. That means that

names will not appear on any papers where information is recorded. All forms will be coded to achieve confidentiality. The attached master list will help correlate the names of

participants to the corresponding code numbers. Once the data are collected and analyzed, the master list will be destroyed. All other forms will be retained for three years in a locked file in the principal investigator's office.

INSTRUMENTATION

This session will involve completing a questionnaire, depth perception test and a visual acuity test. Once these tests are complete, observers will view plastic parts with different levels of sink marks. The attached questionnaire will be used to provide general

information about human observers such as age, level of education and employment status. Also attached is a brochure explaining the Stereo Fly Stereopsis Test. This test will be used to determine each observer's ability to see depth. The final test is the

attached Effron Wall Chart to determine an observer's visual acuity. All documents will

be kept confidential using the attached coding sheet.

INFORMED CONSENT

Please see the attached informed consent form that will be given to all human observers prior to their participation in the project.

105

Text Read to Human Subjects

You are invited to participate in a research project entitled "Quantifying a Key

Injection Molding Attribute Defect." This research is intended to study how human

subjects are able to visual perceive an injection molding defect called sink marks. Sink

marks are a shallow depression or dimple on the surface of a finished plastic part due to shrinkage or low fill of the mold cavity. This project is Kris Horton's thesis project.

Participation in this project will involve a one half-hour session with Kris Horton

in the Prince-Maplewood plant color viewing room. This session will involve

completing one questionnaire for general information, visual acuity test and a viewing of plastic parts with different levels of sink marks.

If you decide to participate in the project, you may quit at any time without

penalty. If you have questions or concerns about this study, you may contact either Dr.

Paul Engelmann at 616-387-6527 or Kris Horton at 616-394-6679. You may also contact Western Michigan University and speak with the Chair of Human Subjects Institutional Review Board of Western Michigan University at 616-387-8293 or the Vice President for Research at 616-387-8298 with any concerns that you have.

College of Engineering and Applied Sciences

Department of Industrial and Manufacturing Engineering

Kalamazoo. Michigan 49008-5045

616387

FAX 616

4,o'/J J., N A; 106 rov :' 7 �V/fc

eC/ 1or • S ly1G Use . / '."ltv U

WESTERN MICHIGAN UNIVERSITY Or-,

10r 0n� /?. ;1v�frsQ u5-c .z ,. } ear fr% �I/is 1,

Principal Investigator: Dr. Paul Engelmann � ;f 9? cr,1/e_. Research Associate: Kris Horton lfslJ?s '-(. �

I h b . . d . . . h . · l d "Q 'fy' 01zqjh 1-(. ave een mv1te to part1c1pate m a researc project entlt e uantl mg a Key Injection<-<

Molding Attribute Defect." I understand that this research is intended to study how human subjects are able to visual perceive an injection molding defect called sink marks. Sink marks are a shallow depression or dimple on the surface of a finished plastic part due to shrinkage or low fill of the mold cavity. I further understand that this project is Kris Horton's thesis project.

My consent to participate in this project indicates that I will be asked to attend one, half hour session with Kris Horton. I will be asked to meet Kris Horton for these sessions at Prince Corporation in the Maplewood Color viewing room. This session will involve completing one questionnaire, a depth perception test , a visual acuity test and a viewing of plastic parts with different levels of sink marks. I will also provide general information about myself such as my age, level of education and employment status.

As in all research, there may be unforeseen risks to the participant. If an accidental injury occurs, appropriate emergency measures will be taken; however, no compensation or treatment will be made available to me except as otherwise stated in this consent form. I understand that one potential risk of my participation may involve discomfort to the eyes from viewing a number of plastic parts. I understand the Kris Horton is prepared to provide an opportunity for me to stop and rest my eyes at any time during the session.

I understand that all of the information collected from me is confidential. That means that my name will not appear on any papers on which this information is recorded. The forms will all be coded, and Kris Horton will keep a separate master list with the names of participants and the corresponding code numbers. Once the data are collected and analyzed, the master list will be destroyed. All other forms will be retained for three years in a locked file in the principal investigator's office.

I understand that I may refuse to participate or quit at any time during the study without it affecting my employment at Prince Corporation. Ifl have any questions or concerns about this study, I may contact either Dr. Paul Engelmann at 616-387-6527 or Kris Horton at 616-394-6679. I may also contact the Chair of Human Subjects Institutional Review Board at616-387-8293 or the Vice President for Research at 616-387-8298 with any concern that I have.My signature below indicates that I understand the purpose and requirements of the study andthat I agree to participate.

Signature Date

107

CODING SHEET FOR

HUMAN EVALUATION OF SINK MARKS

CODE ( on questionnaire) NAME

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Research Questionnaire Quantifying a Key Injection Molding Attribute Defect

What is your age range? 18-25yrs. 26-35yrs. 36-45yrs. 46-55yrs. 56-65yrs. ( circle one)

How many years of education have you completed?: ( circle one)

K 1 2 3 4 5 6 7 8 9 10 11 12, GED , 1 2 3 4 5 , 1 2 3 4 undergrad graduate college

college

3. Number of years working on plastic products:

Do you wear corrective lenses? (circle one) Yes, No

If yes to #4, do you wear contacts, glasses or both?(circle one) contacts, glasses, both

If yes to #4, what corrective lenses do you wear at work? (circle one) contacts, glasses, both

108

□

If yes to #4, what corrective lenses do you wear at home? (circle one) contacts, glasses, both

If yes to #4, are you near-sighted or far-sighted? (circle one) near-sighted, far-sighted

9. Do you have color blindness? (circle one) yes, no

Visual Acuity Score = Left Eye ____ _ Right Eye ____ _

109

Check Sheet D

Part Number Area-1 Area-2 Area-3 Area-4 Area-5

2350

. 2200

2050

1900

1750

1500

1350

1200

900

600

500

400

300

150

Appendix D

Surface Scans From Third Measurement Series (Painted and Non-Painted Parts)

on Coordinate Measurement Machine

110

Surface Scans From Third Measurement Series (0 psi /NP - 50 psi /NP). (P=Painted Parts, NP=Non-Painted Parts)

Opsi - Pack Pressure

S 1.0000 -r--- - ---- --- - ----------<

--

.; 0.5000 i- ---------:��:::�,J__=-_--=��-- -� c:,:i

=

S 0.0000 _______ ______ _ _ _____ _______, ....

Q

Scan Point Number

50psi - Pack Pressure

--

s S 1.0000 +------------ ------------<

--

= 0 ....

c:,:i

= �

s ....

Q -0.5000 �-----------------�

Scan Point Number

111

m)

I 0 ......

0

0 ......

C.1

1 C.1

1 0

01

01

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 1

1 35

38

69

75

103

112

137

149

171

186

205

223

239

260

273

297

307

341

334

371

375

409

408

443

445

; 47

7 48

2 51

1 51

9

Surface Scans From Third Measurement Series (100 psi /NP - 150 psi IP).

(P= Painted Parts; NP=Non-Painted Parts)

1 00psi - Pack Pressure

,_ 1.5000 ,---- --- - - - - ------ - - - --------,8 8 1.0000 -j- --------- --------------,

--

= 0 ....

t,.)

= QI

8 ....

� -0.5000 �-----------------�

Scan Point Number


e 8 1.0000 -+-------------------

--

= 0 ....

t,.)

= QI

8 ....

� -0.5000 �--- - - --- - ------- -�

Scan Point Number

112

0 0

-"

0 0

0 01

01

0

01

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 1

1 35

35

69

69

10

3 10

3 13

7 13

7 17

1 17

1 20

5 20

5 23

9 23

9 27

3 27

3 30

7 30

7 34

1 34

1 37

5 37

5 40

9 40

9 44

3 44

3 47

7 47

7 51

1 51

1

Surface Scans From Third Measurement Series (200 psi /NP - 250 psi /NP). (P = Painted Parts; NP= Non-Painted Parts)


-

£ 1.0000 -r----- --=::.�-��;;;;;::::::-------1=

.s 0.5000 +---�...-,f'----------------'¥'--�,--------1 t:l.l

=

e 0.0000 _________ _ _ _ _ _________ _ ·-

�

= 0 ·-

t:l.l

=�e·-

Scan Point Number


� -0.5000 �-- - - - - ---------- -�

Scan Point Number

113

1 35

69

103

137

171

205

239

273

307

341

375

409

443

I 41

1 I

511

0 0 0 0 0

0 01

0 0 0

(mm

) ......

......

0

01

0 0

0 0

0 0

1 34

67

100

133

166

199

232

265

298

331

364

397

430

463

496

529

6 01

0 0 0

\ ) )

J__

......

01

0 0 0

Surface Scans From Third Measurement Series (300 psi IP - 350 psi /NP).

(P=Painted Parts; NP=Non-Painted Parts)

= 0 ....

r,:i

= �

e ....


� -0.5000 �------------------

Scan Point Number


e 1.5000

_§, 1.0000 -r- --------:-�::;;;;;;;;��;;;:;;;;;;:;;::=-------, =

.s 0.5000 +-----,.___ ___________ -3-_,_------1

r,:i

5 0.0000 --------------- - - - - -e ....

� -0.5000 �-- ---------------

Scan Point Number

114

(mm

) p

0 ......

......

0

c.n

0 c.n

0

0 0

0 0

0 0

0 0

0 0

0 1

~-I

36

1

71

35

69

106

141

\1

103

I

176

137

171

211

205

246

239

281

273

316

307

351

341

386

J 42

1 37

5 40

9 45

6 44

3 49

1 ~/

52

6 47

7 51

1

Surface Scans From Third Measurement Series ( 400 psi IP - 450 psi /NP). (P=Painted Parts; NP=Non-Painted Parts)

= 0 ...

r,.i

= Q)

e ...


Q -0.5000 --- - --------------�

Scan Point Number


S 1.5000

! 1.0000 r------=::;�;;;;;;;::;::;::;;;;;;=;;;;;;;;;;;:::::=------,

.s 0.5000 +--�-"'--------- -----=,.,,.__--------j r,.i

5 0.0000 +------------------------"'

e ...

Q -0.5000 �-----------------�

Scan Point Number

115

n (m

m)

...>.

...

>.

0 01

0

01

0 0

0 0

0 0

0 0

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1

\-36

1

71

35

69

106

141

\ 10

3

176

137

171

211

205

246

239

281

273

316

307

351

341

386

/ 42

1

375

456

409

443

491 _

j 52

6

477

511




-

e _§, 1.0000 +-- ----- -----------------< = 0 ...

r:l.l

= QJ

e ...

� -0.5000 �-----------------�

Scan Point Number


e 1.5000

E, 1.0000 +-------==;:;:::::;:;;:;::::;;;;��:::::==--------1

.s 0.5000 +----=-�-------------=-....------1 r:l.l

5 0.0000 - -- --------------- - ------"'\ e Q -0.5000 �------ ------------�

Scan Point Number

116

1 36

71

106

141

I 17

6

211

I 24

6

281

I 31

6 35

1 38

6 42

1 45

6 49

1 52

6

n \ \ ! _)

1 35

69

103

I 13

7 I

171

205

239

273

307

341

375

409

443

477

I 51

1

0 0

0 c.,,

0

0 0

0 0

0

_.,

c.,,

0 0 0



= 0 ....

c:,:i

= Q)

8 ....


� -0.5000 �------------------

Scan Point Number


S 1.5000

,.S 1.0000 -+---- ----- ------------

= .s 0.5000 +------:::aa.--""---------------=�:------,

c:,:i

5 0.0000 ----- - --- ------------8 S -0.5000 �----------------�

Scan Point Number

117

1 36

71

106

141

176

211

246

281

316

351

386

421

456

491

526

\ _)

1 35

69

103

137

171

205

239

273

307

341

375

409

I

443

477

511

(mm

) ......

......

0

(J'1

0

(J'1

0

0 0

0 0

0 0

0 0

0 0

0

Surface Scans From Third Measurement Series (700 psi /NP - 750 psi /NP).



-

� 1.0000 +---- - - - - - - - - ------�

'-'

=

.s 0.5000 ---i--------=---------------------=-,,.---,,-----------------1

c,.i

= <l)

e 0.0000 ---f'--------------- - -�r--<

....

�

Scan Point Number


-

e e 1.0000 ------------ - - -------1

'-'

= 0 ....

c,.i

= <l)

e ....

� -0.5000 __,.___ ___ _ _ ____________ ___,

Scan Point Number

118

I 0 -"

0,

-"

0,

0 0

0 0,

0

0 0,

0

0 0

0 0

0 0

0 0

0 1

\ 0

0 0

1 34

35

67

69

10

3 10

0

137

133

171

166

205

199

239

232

273

265

307

298

341

331

375

364

409

397

430

/1

443

463

477

496

511

529




e 1.5000 � -- - - - - - - - -- - -----�

e '-'

=

.s 0.5000 +- ------=-"""--- ---------------'-..,..,---------i

(I)

5 0.0000 -------- --------- - -----------,,;

S -0.5000 -+----- - ---------------�

Scan Point Number


e 1.5000

S 1.0000 -+------ ----- -------------<

= .s 0.5000 +-----;;;a--�- -----------="'"""'.:-------!

(I)

5 0.0000 --- ---- -- ----------- -------'!

S -0.5000 -+------------- - - - ----�

Scan Point Number

119

m

m

_..

0 0 0 0 1

1 --

-1\-

36

36

71

71

106

106

141

141

I I

176

176

211

211

I 24

6 24

6 28

1 28

1 31

6 31

6 35

1 35

1 38

6 38

6 42

1 42

1 45

6

_IL_

456

491

491

I 1;

526

526 --




-

e _§, 1.0000 -+---------- ---- ---- --------<

= 0 ....

�

= �

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� -0.5000 ...,__ ___ _________ _____ �

Scan Point Number


-

e e 1.0000 +---- - ----------------,

-

= 0 ....

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= �

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� -0.5000 ...,__ _________________ �

Scan Point Number

120

0 0

_._

0 0

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0

0,

0,

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

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35

35

69

69

103

103

137

137

171

171

205

205

239

239

273

273

307

307

341

341

375

375

409

409

443

443

477

477

511

511

Surface Scans From Third Measurement Series (1000 psi /NP - 1050 psi /NP).(P=Painted Parts; NP=Non-Painted Parts)

l000psi - Pack Pressure

-

e e 1.0000 -+-- -- - - ------- ----------<

'-'

= 0 ...

�

= Cl)

e ...

Q -0.5000 --- ---------------�

Scan Point Number


a 1.5000

,,S 1.0000 +--- ------------- ---------,

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� 0.0000 ------------------ -----...

Q -0.5000 -+------------ ------�

Scan Point Number

121

1 36

71

106

141

176

I 21

1

246

281

316

351

386

421

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1 35

69

103

137

171

205

239

273

307

341

375

409

I

443

477

511

0 0 0 0

u,

0 0 0

Surface Scans From Third Measurement Series (1100 psi /NP - 1150 psi /NP). (P=Painted Parts; NP=Non-Painted Parts)


e e 1.0000 ------- - - --- ------� --

= 0 ....

i:,J

= Cl)

e ....

� -0.5000 -+-------------------�

Scan Point Number


5 1.5000

'5 1.0000 -+----------------------;

= .s o.5000 L----=,,I"'��:::=:::::==::::��"'-'="""--�

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5 0.0000 ------ -----------------'\,I

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Scan Point Number

122

0 0

->,.

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211

205

246

239

281

273

316

307

351

341

386

375

421

I 40

9

456

) 44

3

491

477

526

511

I ~

-

Surface Scans From Third Measurement Series (1200 psi IP - 1250 psi /NP). (P=Painted Parts; NP=Non-Painted Parts)


-

e e 1.0000 -+---- - - - - --- ---- - -------1 --

= 0 ...

�

= �

e ...Q

-0.5000 �- -------- - - - - - - --�

Scan Point Number


S 1.5000 -,-------------- -------,

E, 1.0000 -+------------ ---------,

=

.s 0.5000 j_ __ ��-::::::::::�==��.....,..._--____j �

5 0.0000 ---- --- - - - ----------------""d

... Q -0.5000 _,____ _________ _ _ _ _ _ __ �

Scan Point Number

123

m

..... 0

(.11

0 0

0 0

0 0

1 1

\ 36

71

35

106

69

103

141

137

176

211

I 17

1 20

5

246

239

281

273

316

307

351

341

386

375

421

409

456

~)

491

443

526

477

511




-

e e 1.0000 +----------------------j --

= 0 ·-

c-,}

=Q)

e·-

Q-0.5000 �--- - -------------�

Scan Point Number


a 1.5000 -r----- - -------- -- - -----,

-5, 1.0000 +---------------------j

= .s 0 .5000 -l----��::::::::::::::::::::::::::::::�--..:------� c-,}

5 0.0000 -------------- -- ------�e ·-

Q -0.5000 ---'-----------------------�

Scan Point Number

124

r

......

0 (J

'I (J

'I 0

0 0

0 0

0 0

0 0

1 1

,\ 36

71

35

106

69

103

141

137

176

211

171

246

205

I I

239

I 28

1 27

3

316

307

351

341

386

375

421

409

456

)1 49

1

443

526

477

511

I. I

Surface Scans From Third Measurement Series (1400 psi /NP - 1450 psi /NP).(P=Painted Parts; NP=Non-Painted Parts)


-

e e 1.0000 -+-------- - - - - - - - - ---------<

._,

= 0 ....

�

= Q)

e ....

� -0.5000 -'--------- --- - - -----�

Scan Point Number


S 1.5000

E, 1.0000 -+-- -- - - -------------

= .s o.5000 L----��:::::=:::::::::��--=---_____j�

� 0.0000 �----- - - -----------"'\;!....

� -0.5000 -'-- -- - - - -----------�

Scan Point Number

125

1 36

71

106

141

176

211

246

281

316

351

386

421

456

491

526

\ ~)

1 35

69

103

137

171

205

239

273

307

341

375

409

443

477

511

p 0 0 0 0

p 01

0 0 0

......

01

0 0 0

Surface Scans From Third Measurement Series (1500 psi IP - 1550 psi /NP). (P=Painted Parts; NP=Non-Painted Parts)


,_

e 1.0000

e --

= 0 0.5000 ...

�

= Q)

0.0000e ...

Q

Scan Point Number


,_

e e 1.0000 +----------------------,

--

= 0 ...

�

= Q)

e ...

Q -0.5000 __,___ _ _________ _ ______ �

Scan Point Number

126

I 0 .....

0 .....

0 0

, c.,,

0

, 0

, 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

1 1

35

34

69

67

103

100

137

133

171

166

205

199

239

232

273

265

307

298

341

331

375

364

409

397

443

430

477

463

496

511

529




1.5000 -

6 1.0000 6 '-'

= 0 0.5000 ....

c,:i

= Q)

6 0.0000 ....

�

Scan Point Number


-

a 6 1.0000 -+-------------------

'-'

= 0 ....

c,:i

= Q)

6 ....

� -0.5000 �-----------------�

Scan Point Number

127

I 0 0

0 _,,_

0

01

01

01

0 0

0 0

0 0

0 0

0 0

0 0

1 1

35

34

69

67

103

100

137

133

171

166

205

199

239

232

273

265

307

298

341

331

375

364

409

397

443

430

477

463

496

511

529




--

e 1.0000 e -

= 0 0.5000 ....

r,')

= �

e 0.0000 ....

�

Scan Point Number


--

e e 1.0000 +------------------------,

-

= 0 ....

r,')

= � e ....

� -0.5000 -'------------- --------'

Scan Point Number

128

I 0 --

" !='

0

--"

0 CJ'1

CJ'1

CJ'1

CJ'1

0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

1 1

35

34

69

67

103

100

137

133

171

166

205

199

239

232

273

265

307

298

341

331

375

364

409

397

443

430

477

463

511

496

529

Surface Scans From Third Measurement Series (1900 psi IP- 2050 psi IP).



e 9 1.0000 -+-------------- - - -------l

'-"

=

.s 0.5000 +------,="',,,=.--------- --- -------'-�---j

rl:l

= <l)

9 0.0000 ----- - ----------------l

..... �

Scan Point Number


--

e e 1.0000 -+--------------------1

'-"

= 0..... rl:l

= <l)

a .....

� -0.5000 -'--------------------�

Scan Point Number

129

I 0 ...

.lo.

01

....lo

. 01

0

0 0

01

0 0

01

0 0

0 0

0 0

0 0

0 0

1 0

\ 0

0 1

34

35

67

69

100

103

137

133

171

166

205

199

239

232

273

265

307

298

341

331

375

364

409

397

443

430

463

j__

477

496

511

529

Surface Scans From Third Measurement Series (2200 psi IP - 2350 psi IP).



-

e 1.0000 e ,_,

= 0 0.5000 ·-

� = �

e 0.0000 ·-

�

Scan Point Number


-

e e 1.0000 -+-- ----- ---------------<

,_,

= 0 ·-

� = � e ·-

� -0.5000 -'------------- ---------'

Scan Point Number

130

I 0 ......

0

0 ......

01

01

0

01

01

0 0

0 0

0 0

0 0

0 0

0 0

0 0

1 0

1

35

34

69

67

103

100

137

133

171

166

205

199

239

232

273

265

307

I 29

8

341

331

375

364

409

397

443

430

477

463

511

496

529

Appendix E

Surface Scans From First Measurement Series (Non-Painted Parts) on Coordinate

Measurement Machine

131

Surface Scans From First Measurement Series - Non-Painted Parts (0 psi - 50 psi).


-

� 1.0000 -+---------------------l

--

= .s 0.5000 -+----- -- -----��- -- ------�� = �

e 0.0000 -p,,,,,......_..,,,__ ___ ____________ _.:.._---1

....

�

Scan Point Number


-

e e 1.0000 -+------------------,

--

= 0 ....

� = �

e ....

� -0.5000 �------------ -----�

Scan Point Number

132

I 0 ......

.

9 0

.......

(JI

0 01

(J

I 0

01

0 0 0

0 0

0 0

0 0

0 0

0 0

0 1

,~-

1 13

14

~· 27

25

40

37

53

49

66

61

79

73

92

85

97

10

5

109

118

121

131

133

144

145

157

157

170

169

183

181

196


1 OOpsi - Pack Pressure

-. 1.5000 ,------ - ---------------------,

s S 1.0000 +----------------------1

'-'

= 0 ...

C'-l

= cu

s ...

� -0.5000 � ------------- - - - ---'

Scan Point Number

l SOpsi - Pack Pressure

-

s S 1.0000 -+---------------------<

'-'

= 0 ...

C'-l

= cu

s ...

� -0.5000 �-----------------�

Scan Point Number

133

0 0

_._

0 0

0 CJ1

CJ1

0

CJ1

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 1

1 12

14

23

27

34

40

45

53

56

66

67

79

92

78

105

89

118

100

131

111

144

122

157

133

170

144

183

155

196



e 8 1.0000 -+-------- - -------------,

_,

=

.s 0.5000 -+-- ----- - - -�,._,_-______ ___ _

rl.l

=

8 0.0000 --+-��---..:...==---- - --- ---- ------==--------, ...

�

� � 'T""9 � � � "t"- sir- � � � � � � � � �

� N M � � � � ro m O � N M � � �

Scan Point Number


-

8 8 1.0000 -t- ---------- - ------------1

_,

= 0 ...

rl.l

= Cl)

8 ...

� -0.5000 �-- - - -------------�

Scan Point Number

134

1 12

23

34

45

56

67

78

89

100

111

122

133

144

155

166

0 0

o 01

0

0 0

0 0

0

_._

01

0 0 0

1 1 1 1 1 1 1

I 0 01

0 0 0

0,

0 0 0



e e 1.0000 ----------------- ------{ --

= 0..... �

= �

e..... � -0.5000 �-----------------�

Scan Point Number


e 1.5000

_§, 1.0000 -+-----------------------,

= .s 0.5000 +------- - - ----.-___.,--=---- ------, �

5 0.0000 +--�---------------------1 e S -0.5000 -'-----------------------'

Scan Point Number

135

0 0

......

0 u,

u,

0

0 0

0 0

0 0

0 0

1 1

14

13

25

27

37

40

49

53

61

66

73

79

85

92

97 I

10

5 I

) 10

9 11

8 12

1 13

1 13

3 14

4 14

5 15

7 15

7 I

170

169

183

181

Surface Scans From First Measurement Series - Non-Painted Parts (400 psi- 450 psi).


-

e e 1.0000 -+-------- ---- -------------<

._,

= 0

•.-1 r'-l

= �

e •.-1

Q -0.5000 � ---- -- -----------�

Scan Point Number


-

e e 1.0000 +--------------- ---------;

._,

= 0

•.-1 r'-l

= �

e •.-1

Q -0.5000 --'--------- -- - --------�

Scan Point Number

136

0 0

...>.

0

0 ...

>.

0 C.1

1 C.1

1 0

01

01

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

1 1

13

14

25

27

37

40

49

53

61

66

73

79

85

92

105

97

118

109

131

121

144

133

157

145

170

157

183

169

196

137



1.5000 -

= = 1.0000 _,

= 0 0.5000 ....

f.f.l

=

� ---�

-....

QJ 0.0000

= -----

....

� -0.5000

Scan Point Number


- 1.5000= = 1.0000 _,

= 0 0.5000 ....

� _,

f.f.l --

= 0.0000 QJ

= -

....

-0.5000�

Scan Point Number

1 14

27

40

53

66

79

92

105

118

131

144

157

170

183

1

I

1 14

27

40

53

66

79

92

105

118

131

144

157

170

183

196

I

, \ I J I



e e 1.0000 -t-------- ---------------j

'-'

= 0 .....

VJ

= <l)

e .....

� -0.5000 �---- -------- - ---------'

Scan Point Number


- 1.5000e e 1.0000

'-'

= 0 0.5000 .....

VJ

= 0.0000 <l)

e

--

____./ ------

.....

-0.5000 �

Scan Point Number

138

1 12

23

34

45

56

67

78

89

100

111

122

133

144

155

166

\ I

1 14

27

40

53

66

79

92

105

I 11

8 13

1 14

4 15

7 17

0 18

3 19

6

0 !='

.....

0 CJ

1 CJ

1 0

0 0

0 0

0 0

0 0



--

� 1.0000 ---t------- - ---- - - - - - -------1

'-'

=

.s 0.5000 -i----- - - -----__,._---"'==-----------------1 {I}

= Q)

5 0.0000 ---i.--,-c..___----- - - - - --- - - - --------1

....

Q

Scan Point Number

7 SO psi - Pack Pressure

1.5000 --

e e 1.0000

'-'

= 0 0.5000 ....

{I}

=

--

---�

Q) 0.0000e

�-

....

Q -0.5000

Scan Point Number

139

1 17

33

49

65

81

97

113

129

145

161

177

193

209

225

241

'

1 1

1 13

25

37

49

61

73

85

97

109

121

133

145

157

169

181

I 0 ->

,.

01

01

0 0

0 0

0 0

---- )

140



1.5000

e e 1.0000 __, = 0 0.5000 ... �

--

_f --= �

<l) 0.0000

e -----

...

-0.5000

Scan Point Number


- 1.5000a e 1.0000 __, = 0 0.5000 ...

__./' �

= 0.0000 -

e ...

-0.5000Q ..- N C') s::f" I.(') (.D r-- ro 0) 0 ..- N C') s::f" I.(') (.D

..- N C') s::f" I.(') (.D r-- ro 0 ..- N C') s::f" I.(') (.D ..- ..- ..- ..- ..- ..- ..-

Scan Point Number

e \ I

1 13

25

37

49

61

73

85

97

109

121

133

145

157

169

181

D

)

\ \ '



1.5000 -

8 1.0000 8 _,

= 0 0.5000 ...

ti}

-'----

= -<l)

0.0000 8

-_,..,,--

...

� -0.5000

Scan Point Number


-

8 8 1.0000 +--- - - - - - ---- - - - --------,

_,

= 0 ...

ti}

= <l)

8 ...

� -0.5000 -'-------- ------- - - -�

Scan Point Number

141

0 0

.......

0 (J

I 0

, 0

0 0

0 0

0 0

0 0

1 1 12

13

23

25

34

37

45

49

56

61

\ 67

73

78

85

89

97

J \ 10

0 10

9

111

121

122

133

133

145

144

157

155

169

166

181

j

142



-1.5000

s s 1.0000 ..._,

= 0 0.5000 ...

(;l.l

-

_/ = -

-.____

-

a)0.0000

s -----

...

� -0.5000

Scan Point Number


- 1.5000s s 1.0000 ..._,

= 0 0.5000 ...

(;l.l �...,,......___

= 0.0000a)

- � �

s ...

-0.5000�

Scan Point Number

1 14

27

4 5 6 7 92 0 3 6 9

105

118

131

144

157

170

183

I

'

i 1

l

1 14

27

40

5 6 7 9 3 6 9 2 10

5 11

8

131

144

157

170

183

196

\ ) \ \ I I l



-1.5000

e e 1.0000

'-' = 0 0.5000•...C r,:i

= Q) 0.0000e

� - � ----

•...C

� -0.5000

Scan Point Number


a 1.5000

-8, 1.0000 -+----------------------1

=

-� 0.5000 r------- -=7-�;;;;;;::;:;:::::==::::=1

5 0.0000 �----==-------------------------1e

•...C � -0.5000 �-----------------�

Scan Point Number

143

1 1 ----

14

14

27

27

• 40

40

53

53

66

' 66

79

I

79

92

92

105

105

118

. 11

8 13

1 13

1 14

4 14

4 15

7 15

7 17

0 17

0 18

3 i

183

196



1.5000 ---,--- -- - - - - --------------�

E, 1.0000 +--- -- -- -- -- - - - - - - ---------j

= 0 ...

= a)

...

0.5000 --+----- - - ------------------<

0.0000 +-,.......-:=:--=------ - ---- ------ -----=---.1

� -0.5000 ---'----- -- -------- -- -- - - -�

Scan Point Number


-- 1.5000 e e 1.0000

'-'

= 0 0.5000 ... -

Cl.l

= -

a) 0.0000e ...

-0.5000� ..... -.::;I- r--.. 0 C") (0 0) N LO co ..... -.::;I- r--.. 0 C") (0

..... N -.::;I- LO (0 r--.. 0) 0 ..... C") -.::;I- LO r--.. co 0) ..... ..... ..... ..... ..... ..... ..... .....

Scan Point Number

144

' \ '

1 14

I

27

40

53

66

79

92

105

I 11

8 I

131

144

157

170

183

196

m

s m

)

145



1.5000

e e 1.0000 __,

= 0 0.5000 .... � = Q)

0.0000e

� ---

....

� -0.5000

Scan Point Number


-- 1.5000 e e 1.0000 __,

= 0 0.5000 ....

_,____ t:l'.l

= � Q) 0.0000

e ....

-0.5000� ....-- co ....-- co ....-- co ....-- co ....-- co ....-- co ....-- co ....-- co

....-- C") "'-t" co t- 0) 0 N C") LO co 00 0) ....-- N ....-- ....-- ....-- ....-- ....-- ....-- ....-- N N

Scan Point Number

s )

1 '

14

27

40

53

66

79

\ 92

10

5 11

8 13

1 14

4 '

f 15

7 17

0 18

3 19

6 l

l l



1.5000 e e 1.0000 _,

= 0 0.5000 ....

(l.l

= -� 0.0000 e ....

� -0.5000..- -.;t- r-- 0 C') (0 (j) N LO co ..- -.;t- r-- 0 C') (0

..- N '<;f" LO (0 r-- (j) 0 ..- C') -.;t- LO r-- co (j) ..- ..- ..- ..- ..- ..- ..- ..-

Scan Point Number


a 1.5000

S 1.0000 -+--------------------------1

=

.s 0.5000 +------------------- ----1

(l.l

f 0.0000 L-�::'.'.::'.:::::::=:::::::=�__:_====:::::�d e....

� -0.5000 �------ -----------�

Scan Point Number

146

)

1 ---

14

27

40

53

66

' 79

92

! 10

5 11

8 (

131

144

157

170

i 18

3


1.5000 -

e 1.0000 e

'-'

= 0 0.5000 ....

VJ

= Q)

e 0.0000 ....

Q -0.5000

-

e


-�Al ----

-

� � m M � � � m M � � � m M � � � N � � � ro m � N � � ID ro m �

.,- .,- .,- � .,- .,- .,- N

Scan Point Number


e 1.0000 __________________ _ '-'

= 0 ....

VJ

= Q)

e ....

Q -0.5000 -'-- -- - - - --- ------- -----'� ID � ID � ID � ID � ID � ID � ID � ID

� M � ID � m O N M � ID 00 m � N � � � � � � � N N

Scan Point Number

147

.. -

1.5000 ~------------------

0.5000 r---_-_ -__:.~~r-=.;;;;;;;:::::;:::::;::::::=:==~7 0.0000 ..i-,.~=-----------------~



,_

� 1.0000 ---t----- - - - -------- -------i

..._,

= .s 0.5000 ---i-------------------==--------------1v.i

= Cl)

9 0.0000 --l-"""'=----- - ------ -----------1

...

�

Scan Point Number


1.5000 �----------- ---- - - --,_

e e 1.0000 +---------- - - - ----------j ..._,

= 0 ...

v.i

= Cl)

e ...

0.5000 -+--------------------------,

0.0000 L��::::==:::==---�==:::::::::::::-� -0.5000 ..L._ _________________ �

Scan Point Number

148

I 0 ......

. 0,

01

0

0 0

0 0

0

1 1

15

19

29

37

43

55

57

73

71

91

85

109

99

127

113

145

127

163

141

181

155

199

169

217

183

235

197

253

211

271

289

L

149



1.5000

a 1.0000 a --

= 0 0.5000 ....

fl:)

= Q)

0.0000 � a .... -........ �

-0.5000

..- C"') L{) r-- 0) ..- C"') L{) r-- 0) ..- C"') L{) r-- 0) ..-..- N C"') -.;t- (0 r-- co 0) 0 N C"') -.;t- L{) (0 co

..- ..- ..- ..- ..- ..- ..-

Scan Point Number


1.5000

a a 1.0000 --

= 0 0.5000 ....

fl:)

= Q)

0.0000a ....

� -0.5000

..- L{) 0) C"') r-- ..- L{) 0) C"') r-- ..- L{) 0) C"') r-- ..-..- N -.;t- L{) r-- co 0) ..- N -.;t- L{) (0 co 0) ..-

..- ..- ..- ..- ..- ..- ..- N

Scan Point Number

Appendix F

Surface Scans From Second Measurement Series (Non-Painted Parts) on Coordinate

Measurement Machine

150

Surface Scans From Second Measurement Series - Non-Painted Parts (0 psi - 50 psi).


-

� 1.0000 ---+--------------- - - -----<

__,

=

-� 0.5000 -j---------:�;;;;;;;;--��;;;;;;;

��-....... ;;;;;;:::=-------j= Cl)

9 0.0000 --l"<--=-----------------�----""'\

...

�

Scan Point Number

SOpsi - Pack Pressure

-

e e 1.0000 ---+---------------- ------< __,

= 0 ...

c-,.i

= Cl)

e ...

� -0.5000 ---+-------------------�

Scan Point Number

151

I 0 .....

0 0

..... u,

u,

0

()1

()1

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 1

1 >

32

32

63

63

94

94

125

125

156

156

187

187

218

218

249

249

280

280

311

311

342

342

373

373

5 40

4 40

4 43

5 43

5 46

6 46

6 49

7 49

7

152

Surface Scans From Second Measurement Series - Non-Painted Parts (100 psi- 150 psi).


__ 1.5000 � ---- ------------- - ---� e e 1.0000 +-- ---- - - -=---:------:-:-F----- -----"e.____----"",._____, .._,

= 0 ....

�

= Q)

e ....

Q -0.5000 �-------- - --- - - ---�

Scan Point Number


--

e e 1.0000 +------------- ----------1

.._,

= 0 ....

�

= Q)

e ....

Q -0.5000 -'---- ----------------�

Scan Point Number

0 0

0 0

->.

o 0,

0

0,

0,

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 1

1 32

33

63

65

94

97

125

129

156

161

187

193

218

225

249

257

280

289

311

321

342

353

373

385

404

417

435

449

) 46

6 48

1 L

497

153



-

e 1.0000e --

= 0 0.5000 ...

� = �

0.0000e ...

Q

Scan Point Number


-

e e 1.0000 -l----- - --- - --------------l

--

= 0 ...

� = �

e ...

Q -0.5000 -'-------- - - - ------ ----

Scan Point Number

I 0 ...

.lo.

!='

0 ...

.lo.

01

0,

01

0 01

0

0 0

0 0

0 0

0 0

0 0

0 0

0 0

1 1

32

32

63

63

94

94

125

125

156

156

187

187

218

218

249

249

280

280

311

311

342

342

373

373

404

404

435

435

466

466

497

497

154



-

e e 1.0000 +----- ------------------1

--

= 0 ....

l:"'-l

= Cl)

e....

� -0.5000 ------- -----------�

Scan Point Number


8 1.5000

-$ 1.0000 +------------------------,

= .s 0.5000 -1----__,,..=--------- ---=......,.-------j

l:"'-l

� 0.0000 -f"----------- - - --------1

S -0.5000 �-----------------�

Scan Point Number

0 0

..... 0

CJ'I

CJ'I

0 0

0 0

0 0

0 0

0

1 1

33

\ 32

65

63

97

94

129

125

161

I 15

6

193

187

225

218

257

249

289

280

321

311

353

342

385

373

417

/_

404

449

435

481

I_

_ 46

6 49

7

155

Surface Scans From Second Measurement Series - Non-Painted Parts ( 400 psi - 450 psi).


a e 1.0000 ---------- - - - - - - - --------, ..._,,

= 0 ·

(:I}

=�

e·-

� -0.5000 � -- - - ------- ----- -�

Scan Point Number


9 1.5000

-5, 1.0000 +---------- -- - ----- -------1

= .s 0.5000 -L-----��'.'.'::::��:::"'.:�-....-=-----�

(:I}

5 0.0000 -40=-------- ---------------'"� e Q -0.5000 �---------- - - - ----�

Scan Point Number

0 0

..... 0

01

01

0 0

0 0

0 0

0 0

0

1 1

33

32

65

63

97

94

129

125

161

156

193

187

225

218

257

249

289

280

321

311

353

342

373

385

1/i I

404

417

435

449

466

481

_J_

-

497

156 Surface Scans From Second Measurement Series - Non-Painted Parts (500 psi - 550 psi).


-

e e 1.0000 ---t---- - ------- - ---- ---------1

_,

= 0 ....

�

= Q)

e ....

� -0.5000 � ----- - --- - ---- - ---

Scan Point Number


S 1.5000

-5, 1.0000 -+----- -------------

= .s 0.5000 +----�-=------- - - -�....----�

5 0.0000 ---ir=---- ---------------------

9 Q -0.5000 -------------------

Scan Point Number

1 33

65

97

129

I 16

1

193

225

257

289

I 32

1

353

385

411

I 44

9 48

1

1 32 I

63

94

125

156

187

218

249

280

311

342

373

404

435

466

497

0 0 0 0

01

0 0 0

.....,,.

01

0 0 0

157



-

e e 1.0000 -+--------------------------i --

= 0 ....

r,.i

= Q)

e ....

Q -0.5000 -'--------------------------'

Scan Point Number


8 1.5000 -,-------------------------,

-5, 1.0000 --+--- ---- -------------------,

= .s 0.5000 -t-----�-��----.....=-----ir,.i

� 0.0000 -..-=:---------------------==-.

i5 -0.5000 ...,___ __________________ ___,

Scan Point Number

0 0

..... 0

u, u,

0 0

0 0

0 0

0 0

0

1 1

33

32

65

63

97

94

129

125

161

156

193

187

225

218

257

249

289

280

321

311

353

342

385

373

I

404

417

I 43

5 44

9 46

6 48

1 49

7

158



-

§ 1.0000 +------- -----------------1

--

=

.s 0.5000 +----�--=------------�"""""

:----l

� = � e 0.0000 -f"------ ------ - - ------------,

·-

�

Scan Point Number

7 SO psi - Pack Pressure

-

e e 1.0000 -+------- ---------- - -----1 --

= 0 ·-

� = � e ·-

� -0.5000 -'---------------------'

Scan Point Number

I 0 _,.

0

0 _,

. 01

(J

l 0

(Jl

01

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 1

1 32

32

63

63

94

94

125

125

156

156

187

187

218

218

249

249

280

280

311

311

342

342

373

373

404

404

435

435

-~ •• 46

6 46

6 j_

_ 49

7 49

7

159



-

a a 1.0000 -+--------- - - - --- - - ---------<

'-'

= 0 ...

� = Cl)

a ...

� -0.5000 ---'------------- --- ------�

Scan Point Number


- 1.5000a s 1.0000

'-'

= 0 0.5000 ...

� = 0.0000 Cl)

s

� -

I� ·---....

... -0.5000�

Scan Point Number

0 0

......

0 u

, u

, 0

0 0

0 0

0 0

0 0

1 1

33

32

65

63

97

94

129

125

161

156

193

187

225

218

257

249

289

280

321

311

353

342

385

373

417

404

449

435

481

466

II 49

7

160



-

e e 1.0000 -t------- -------------------1

= 0 ...

r,i

= �

e ...

� -0.5000 --'-------------------�

Scan Point Number


-

e e 1.0000 -+----------------- -------,

._,

= 0 ...

r,i

= �

e ...

� -0.5000 ...,__ _________________ �

Scan Point Number

1 32

63

94

125

156

187

218

249

280

311

342

373

404

435

466

497

0 0

0 CJ1

0

0 0

0 0

0

......

CJ1

0 0 0 1 32

63

94

125

156

187

218

249

280

311

342

373

404

435

466

497

0 0

0 CJ1

0

0 0

0 0

0

( ......

CJ

1 0 0 0

161



e e 1.0000 -+---------------------<

_,

= 0 ....

r,.i

= �

e ....

Q -0.5000 ---'------ - - --------------'

Scan Point Number

1 0S0psi - Pack Pressure

- 1.5000e e 1.0000 _,= 0 0.5000 ....

r,.i

= 0.0000 �

e �

-�

....

-0.5000Q

Scan Point Number

0 0

.......

0 (J

I c.n

0

0 0

0 0

0 0

0 0

1 1

33

32

65

63

97

94

129

: 12

5

161

156

193

187

225

218

257

249

289

280

321

311

353

342

385

373

417

404

449

435

481

466

497

162



-

a a 1.0000 ---j-------- - - - - - ----------1

..._,

= 0 ...

�

= Q)

a ...

� -0.5000 -'--- ---- -- - - --- - - -----------'

Scan Point Number


S 1.5000

!, 1.0000 +----- - - ----- - ------------1

= .s 0.5000 +----��=--------- ----------'-:::::e,,,,,,-=:-1 �

� 0.0000 --f'L-------- ------- - ------------,

a Q -0.5000 ---'---------------- -----�

Scan Point Number

0 0

..... 0

0,

0,

0 0

0 0

0 0

0 0

0

1 1

\ 32

I 33

63

65

94

97

12

5 12

9 I

156

161

193

187

225

218

257

249

289

280

321

311

342

353

1 37

3 38

5 40

4 41

7 I

435

449

I 46

6 48

1 _J

_ 49

7

163



e e 1.0000 -+-- -- -- ------ - - -- - ---------<

._,

= 0

•.-C r,.i

= cu

e •.-C

� -0.5000 ---'-------------- ------------'

Scan Point Number


5 1.5000 ,----------- -------- -------,

-$ 1.0000 +-- ----- ------ -------------,

= .s 0.5000 +---------===---------==----------i

r,.i

5 0.0000 --f'L--- ---- ---- - ------ -------,

e S -0.5000 -'--------------------�

Scan Point Number

0 0

-"

0 u,

01

0

0 0

0 0

0 0

0 0

1 1

33

32

65

63

97

94

129

125

161

156

193

187

225

218

257

249

289

280

321

311

353

I 34

2

385

373

417

404

«9

L

435

481

I_

466

--

497

164



-

8 8 1.0000 ---t-------- - - - - - - --------1

,,_,

= 0 ...

r,.i

= Q)

8 ...

� -0.5000 �--------------- ---

Scan Point Number


S 1.5000

E, 1.0000 -+--- --------- - -------

.s 0.5000 ,-----=:;;;;;;;;;;;....-------......._;;;.;;;;;;;�- -r,.i

5 0.0000 �------------- - - - - - --8 S -0.5000 -'-------------- - - - ------�

Scan Point Number

n 0

0 ->

,.

0 CJ

1 CJ

1 0

0 0

0 0

0 0

0 0

1 ~

-1

33

32

65

63

97

94

129

125

161

156

193

187

225

218

257

249

289

280

321

311

353

342

385

373

417

404

449

435

481

466

497

165 Surface Scans From Second Measurement Series - Non-Painted Parts (1400 psi - 1450 psi).


-1.5000 � -- - - - - - - ----- - - - - -�

5 _§, 1.0000 +-- -- - - - - ---- - - - - - - ------1

= 0 .... �

= Q)

5 .... Q -0.5000 �-- - - - - - - - - ----- - -----'

Scan Point Number


9 1.5000

E, 1.0000 +---- -- -- ---- - - - - - - - --------j

=

-� 0.5000 ,---=::;;;;;;;;;;;;.;.a----------;;;;;;;:;::::=---1

� 0.0000 ---l'=-----------------------1

Q -0.5000 -'-------------- --------'

Scan Point Number

0 0

0 C.1

1 0

0 0

0 0

0 1

1 -

33

32

65

63

97

94

129

125

161

156

193

187

225

218

257

249

289

280

321

311

353

342

385

373

404

417

l 43

5 44

9 46

6 48

1 49

7

166



-

� 1.0000 -i----- --- ------- - --------,

...._,

=

-� 0.5000 -i----- -------:-:::;;;;;;;;,..,-,------........ ...;;;;;;;::::=------j

= �

e 0.0000 � -- ---- - - - - - ----------,.....Q

Scan Point Number


-

e e 1.0000 -+-------- - ---- - - --------,

...._,

= 0 ..... �

= �

e ..... Q -0.5000 �--- ----- -- - - -----�

Scan Point Number

I 0 ......

0

0 ......

01

01

0

01

01

0 0

0 0

0 0

0 0

0 0

0 0

0 0

0 1

1 32

32

63

63

94

94

125

125

156

156

187

187

218

218

249

249

280

280

311

311

342

342

373

373

404

404

435

435

466

466

497

497

167



1.5000 -..

e 1.0000 e '-'

= 0 0.5000 .....

r,:i

= �

0.0000 e .....

�

Scan Point Number


e e 1.0000 +-------- - - - ------ ------,

'-'

= 0 .....

r,:i

= � e .....

� -0.5000 �-----------------�

Scan Point Number

I 0 0

0 .....

CJ1

0 C.1

1 C.1

1 0

0 0

0 0

0 0

0 0

0 0

0 1

1 32

32

63

63

94

94

125

125

156

156

187

187

218

218

249

249

280

280

311

311

342

342

373

373

404

404

435

435

466

466

497

497

168



-

§ 1.0000 +------------- - -----------!

'-'

=

-� o.5000 r----=:::::::;::;;::;::;;;::;:�::::::::::::=----- -7

= Cl)

5 0.0000 -vc------- -- - -- ---------'� -� Q

Scan Point Number


-

s 5 1.0000 -+---- - ----------------1

'-'

= 0 -�

r,'l

=Cl)

s-�Q

-0.5000 �------- ---- -------

Scan Point Number

I 0 .....

0 0

..... 01

01

0

0 0

01

01

0 0

0 0

0 0

0 0

0 0

1 0

0 0

---

1 31

36

61

71

91

10

6 12

1 14

1 15

1

176

181

211

211

246

241

281

271

301

316

331

351

361

386

391

421

421

456

451

491

481

Appendix G

Overlaid Surface Scans Based Upon Z-axis Values and Residual Values for Parts Measured During

Repeatability and Reproducibility Tests

169

Overlaid Surface Scans Based Upon Z-axis Values (Top) and Residual Values (Bottom).

1.0

0.8

0.6

§ g'-';;;§ >

0.4

·;;; [/)

0.2i::: -� .§

0.0 Cl

-0.2

1.0

0.8

0.6

I .2 ';;' >

0.4

.9 � � .§ 0.2 Q.) ·-

s � 6 0::: 0.0

-0.2

,. .. , .... _..,,

f� ffi [li -

� �-- 'l\. .. ...... "" -j 11'1' ', �-

/1 . ..

I.L -

r y ,.

� · ... I

.,,, ,.

0 50 100 150 200 250 300 350 400 450 500 25 75 125 175 225 275 325 375 425 475 525

Scan Point Number


i.u..i....

� ,..� �"' ' r..., M.. 1 ....

'I ,,, .. '" I V V ·�-�

0 50 100 150 200 250 300 350 400 450 500

25 75 125 175 225 275 325 375 425 475 525

Scan Point Number


SERlES_l

SER1ES_2

SER1ES_3

SERIES_l

SERIES_2

SERIES_3

170

.. ' . ,

., ,, -~ .... I- ', ,-1~ I I I --

l l ........ .........

-

Overlaid Surface Scans Based Upon Z-axis Values (Top) and Residual Values (Bottom).

1.0

0.8

0.6

§ � 0.4 '-'.;l i::: > .9 "' "' '>< 0.2i::: �

i5 0.0

-0.2

1.0

0.8

0.6

]' .a 0.4 .._, �i::: >.9

;:l 0.2 i::: Q.) ·.;; .§ Q.)

Ci �

0.0

-0.2

i.... ........ .. !" liitfl' ... ., "' •. r'I �

,..,

.. � "' � I/

I\..,'

'

0 50 100 150 200 250 300 350 400 450 500

25 75 125 175 225 275 325 375 425 475 525

Scan Point Number


la., "" .... ., .. , ,.� , .... -,r· " . , 1•·� ..,. ... ... .. ...

0 50 100 150 200 250 300 350 400 450 500

25 75 125 175 225 275 325 375 425 475 525

Scan Point Number


SERIES_l

SERIES_2

SERIES_3

SERIES_!

SERIES_2

SERIES_3

171

--

I ,...., ,·-. ~,.,_.

"'--' I ,-.

I

Jl,f Q.)

·~ r s N

------·· --·······

-

-'I

- I . . ' '" " .,, r ..

I I

Overlaid Surface Scans Based Upon Z-axis Values (Top) and Residual Values

(Bottom).

E 0

i:: -; 0

·;;; en

i:: ·;;;0 (,:I

E N i5

§ .2 .._, ro i::: >.s

;::l i::: :"9 rJ)

cS �

1.0

0.8

0.6

0.4

0.2

0.0

-0.2

1.0

0.8

0.6

0.4

0.2

0.0

-0.2

� ,,,� -� � �-.

l/41 �,..- ��

v V �

�

I

0 50 100 150 200 250 300 350 400 450 500 25 75 125 175 225 275 325 375 425 475 525

Scan Point Number Pack Pressure = 1900 psi

- J ....

" ... " .. , r--

0 50 100 150 200 250 300 350 400 450 500

25 75 125 175 225 275 325 375 425 475 525

Scan Point Number Pack Pressure = 1900 psi

SERIES_l SERIES_2 SERIES_3

SERIES_! SERIES_2 SERIES_3

172

l I ··-

.,,

U_j_W++-+++-t-+tiH--i-1--r--i-n-··

ti)

..

I ·1r , '"' ...

Appendix H

Results From Visual Evaluation Experimentation

for Painted & Non-Painted Parts

173

Results From Visual Evaluation of Sink Mark Areas #1 and #2 (Painted & Non

Painted Parts Overlaid).

Vl

:E .,.:

0

i:: 0

"€0

0

Cll 0

� i:: 0

"€ 0

0 11..

1.0 0.9 0.8 0.7 0.6 0.5 0.4

� .,.. .. · ....

n."/ ______,.-□

o.J

J T I

0.3 0.2 0.1

/□ J,. l

0.0 D

... �ru

. ...

·o. PAINT

'n.___ NONPAINT

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 Depth Value (mm)

..

1.0 o· 00

0.9 /

0.8 0.7 0.6 0.5 0.4

--·

-:7 .oj

:/

-1□

0.3 0.2 0.1 J:

I • )

0.0 _. ( -

Sink Area#l

. .. - •A . -,,.: .

� l.,..----0'"

...-

-

I .. ·o. ..

I --a.____

.... . . .

PAINT � NONPAINT

0.00 0.02 0.04 0.06 0.08 0. 10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 Depth Value (mm)

Sink Area #2

174

r p

h aw

Sin

k M

arks

Pr

p

Wh

Saw

Sin

ar

k

•• _

1 ,.

_ h

, ....

,_ "~

--..

L

----

-,

--t-

.L"-

t---

---"

t--,

.s:!

--+-

--+-

+---

+--+

--1-

--l

", f-

-+-+

--+

---1

---1

--+

----

1--

--1

--1

-"11

--->

--

I ,\

'

C

( r '

', I ! I ll

,._

_

~-

>--

>--

Results From Visual Evaluation of Sink Mark Areas #3 and #4 (Painted & Non

Painted Parts Overlaid).

�

:::E

in

Cl)

0

� i::: 0

"€ 0 0. 0

i:,..

"' .!><: @ � .!><: .5 Cl)

� Cl)

0

� i::: 0 "€ 0

0 .... i:,..

1.0 -·• • 0

0.9

0.8

0.7

0.6

0.5

- ___,.., Q �v

,v

_/r

7 i /

□,P0.4

0.3

0.2

0.1

0.0

/

0 /4 :c:y''

:r I - - '(> PAINT

� - .

c£ (i_ V

I "-o...__ NONPAINT D --

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 Depth Value (mm)

Sink Area #3

1.0 0.9 0.8

-·· -· .. ·- .. .. - . ... .. -0,

-__.a- V

- _,,/

/ -

0.7

0.6

0.5 0.4 0.3 0.2 0.1

<2iQ ,:; _:; :t 1

�□ I ··o .. PAINT

C3/ 0 I u... NONPAINT

0.0

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24

Depth Value (mm) Sink Area #4

175

Results From Visual Evaluation of Sink Mark Area #5 (Painted & Non- Painted Parts

Overlaid).

Cl'.)

0

::! i:: 0

"€ 0

i:i...

1.0

0.9

0.8

0.7

0.6

0.5

0.4

. . ·- ..

� - -

o·)

. . o/ Q

I u

:;

I/

0.3

0.2

0.1

nf

t� 1 ···o PAINT � •,

I --=.__ NONPAINT 0.0

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24

Depth Value (mm)

Sink Area #5

176

rop

h aw

Sin

k M

arks

..

- - -

Appendix I

Results From Pilot Tests for Visual

Evaluation of Sink Marks

177

Results From Pilot Test #2 - Hand-Held Observation

(Sorted by descending order of pack pressure, psi)

Observer#! ARFAI ARFA2 ARFA3 ARFA4 ARFA5 Observer#4

1750 psi y y 1750 psi

1600 y y 1600

1450 y y y 1450

1300 y y y 1300

1150 y y y y y 1150

1000 y y y y 1000

850 y y y y 850

700 y y y y 700

550 y y y y y 550

400 y y y y y 400

250 y y y y y 250

Observer#2 ARFAl ARFA2 ARFA3 ARFA4 ARFA5 Observer#5

1750psi 1750psi

1600 y y 1600

1450 y y y y 1450

1300 y y y 1300

1150 y y y y 1150

1000 y y y 1000

850 y y y y 850

700 y y y y 700

550 y y y y y 550

400 y y y y y 400

250 y y y y y 250

Observer#) ARFAl ARFA2 ARFA3 ARFA4 ARFA5

1750psi

1600 y y y

1450 y y y y

1300 y y y y

1150 y y y y

1000 y y y y

850 y y y y

700 y y y y y

550 y y y y y

400 y y y y y

250 y y y y y

178

ARFAI ARFA2 ARFA3 ARFA4 ARFA5

y y

y y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y y

y y y y y

y y y y y

y y y y y

ARFAI ARFA2 ARFA3 ARFA4 ARFA5

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y y

Results From Pilot Test #2 - 13-Inch Viewing Slot (Sorted by descending order of pack pressure, psi)

Observer #I AREA I AREA2 AREA3 AREA4 AREAS Observer #4

1750 psi 1750 psi

1600 y y y y 1600

1450 y y y y 1450

1300 y y y y 1300

1150 y y y y 1150

l000 y y y y l000

850 y y y y 850

700 y y y y 700

550 y y y y 550

400 y y y y y 400

250 y y y y y 250

Observer #2 AREAi AREA2 AREA3 AREA4 AREAS Observer #5

1750 psi 1750 psi

1600 y y y 1600

1450 y y y y 1450

1300 y y y y 1300

1150 y y y y 1150

l000 y y y y l000

850 y y y y 850

700 y y y y y 700

550 y y y y y 550

400 y y y y y 400

250 y y y y y 250

Observer #3 AREA I AREA2 AREA3 AREA4 AREAS

1750 psi

1600

1450

1300

1150 y

l000 y y y

850 y y y y

700 y y y y y

550 y y y y y

400 y y y y y

250 y y y y y

179

AREAi AREA2 AREA3 AREA4 AREAS

y y y y

y y y y

y y y y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y y

y y y y y

AREA I AREA2 AREA3 AREA4 AREAS

y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y

y y y y y

y y y y y

I

I

I I

Results From Pilot Test #2 - 4-Inch Viewing Slot (Sorted by descending order of pack pressure, psi)

Observer #1 AREA 1 AREA2 AREA3

1750 psi

1600

1450

1300 y y

1150 y y

1000 y y

850 y

700 y y

550 y y

400 y y y

250 y y y

Observer #2 AREA 1 AREA2 AREA3

1750 psi

1600

1450

1300

1150

1000 y

850 y y

700 y

550 y

400 y

250 y y

Observer#3 AREA 1 AREA2 AREA3

1750 psi

1600

1450

1300

1150

1000

850 y y

700 y y y

550 y y

400 y y y

250 y y y

180

AREA4 AREAS

y

y y

y

y

y y

y y

y y

y y

AREA4 AREAS

y

y

y y

y

y

y y

AREA4 AREAS

y y

y y

y y

y y

y y

y y

y y

y y

I

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Documents

Quantifying a Key Injection Molding Attribute Defect - WMU's