IV - Rochester Institute of Technologyedge.rit.edu/content/OldEDGE/public/Archives/P05427/P… · Web viewThis requirement is a quality/yield based. The word contact is similar

Bausch & Lomb Automated Lens Measurement System Project #05427

Executive Summary

Bausch & Lomb brought this project to R.I.T. in order for the Senior Design team

to develop the most cost effective non-contact method of evaluating the center thickness

of a contact lens.

In order to produce a contact lens, a mold is produced, the lens is cast and cured,

then it is hydrated, inspected and packaged for shipment. The current process during the

inspection uses a mechanical contact gauge to determine the center thickness. Once this

measurement is performed, the lens must be discarded. The new requirements specified

by Bausch & Lomb maintain that the new system must be non-contact in order to

eliminate the discarding of any good product.

As stated above, the requirements were determined after consulting with the

Bausch & Lomb Project Coordinator and Sponsor. After this was finalized all of the

other appropriate documentation was put into place. The team could then begin

researching concepts.

This project is different than most because it was extremely research intensive.

The team was required to spend a significant amount of time conducting research into

various technologies and companies that currently exist and could provide the proper

equipment. It is outside of the scope of the project for the team to construct its own

device from scratch, so the research was critical to find appropriate vendors that could be

evaluated.

After the initial large grouping of companies was narrowed down to the top eight

that might be capable of meeting the projects needs, a feasibility assessment was

conducted. This feasibility confirmed the teams’ opinion of what the top three companies

1 2/18/2005


were that should be pursued further. On a parallel track, all of the companies were sent

testing samples. The results from the vendor testing would aid the team in determining

what the top companies were. The top scoring companies from the teams’ opinion,

feasibility assessment and testing results were Lumetrics, Micro-Epsilon, and

Panametrics – NDT.

These top companies will have their units brought into Bausch & Lomb for the

team to conduct an analysis of how capable they are. This analysis, along with final

recommendations, cost benefit analysis, and a manufacturing integration package are

slated to be completed at the end of Senior Design II. In order to accomplish all of these

goals given the one-quarter remaining, the team has adopted a very aggressive timeline in

order to ensure the projects success. As a whole, the team is very proud of the progress

to date, is determined in achieving success, and confident in the path that lies ahead.

2 2/18/2005


EXECUTIVE SUMMARY.......................................................................................................11.0 INTRODUCTION.............................................................................................................5

1.1 BACKGROUND.....................................................................................................51.1.1 Current Measurement Method..........................................................................51.1.2 Desired Method..................................................................................................61.1.3 Possible Points of Integration...........................................................................6

1.2 CONFIDENTIALITY AND PROTECTION OF INTELLECTUAL PROPERTY..................72.0 NEEDS ASSESSMENT................................................................................................8

2.1 NEEDS ASSESSMENT OVERVIEW..............................................................................82.2 REQUIREMENTS – MEASUREMENTS........................................................................8

2.2.1 Non-Contact.......................................................................................................92.2.2 Integration........................................................................................................102.2.3 PLC Interface...................................................................................................102.2.4 User Interface..................................................................................................112.2.5 Extensibility / Flexibility..................................................................................11

2.3 MISSION STATEMENT.............................................................................................112.4 GOALS & OBJECTIVES...........................................................................................122.5 TEAM CHARTER......................................................................................................122.6 CONSTRAINTS..........................................................................................................132.7 RISK ASSESSMENT..................................................................................................152.8 BUDGET...................................................................................................................15

3.0 CONCEPT RESEARCH..................................................................................................163.1 POSSIBLE TECHNOLOGIES AND DISCOUNTED TECHNOLOGIES...........................16

3.1.1 Capacitance Method........................................................................................163.1.2 Laser Triangulation.........................................................................................173.1.3 Optical Spectrometer........................................................................................173.1.4 Laser (Autofocus)............................................................................................183.1.5 Ultrasonic.........................................................................................................193.1.6 Vision System...................................................................................................203.1.7 Mechanical Contact System............................................................................20

3.2 LONG LIST/SOURCES..............................................................................................213.3 SHORT LIST.............................................................................................................223.4 REASONS NOT TO PURSUE CERTAIN COMPANIES................................................223.5 METHOD FOR GATHERING TECHNOLOGY AND COMPANY INFORMATION.........243.6 PATENT SEARCH.....................................................................................................24

3.6.1 Patent Information..........................................................................................253.7 PRODUCT SPECIFICATION RESEARCH...................................................................28

3.7.1 Contact Lens Quick Reference Guide.............................................................283.7.2 Radius of curvature.........................................................................................293.7.3 Mold Information............................................................................................293.7.4 Cost Research...................................................................................................293.7.5 Centration of Lens...........................................................................................30

4.0 FEASIBILITY................................................................................................................31

3 2/18/2005


4.1 THE SHORT LIST REVISITED.................................................................................314.2 JUDGING CRITERIA.................................................................................................324.3 WEIGHTING CRITERIA...........................................................................................324.4 SCORING..................................................................................................................334.5 SAMPLE TEST RESULTS..........................................................................................344.6 THE TOP THREE.....................................................................................................36

5.0 DESIGNS.......................................................................................................................375.1 LUMETRICS.............................................................................................................375.2 MICRO-EPSILON.....................................................................................................395.3 PANAMETRICS.........................................................................................................43

6.0 CONCLUSION...............................................................................................................456.1 SUMMARY................................................................................................................456.2 GOALS FOR SENIOR DESIGN II..............................................................................456.3 ACTION PLAN TO ACHIEVE GOALS.......................................................................45

7.0 References...................................................................................................................47

4 2/18/2005


1.0 Introduction

With increased demand for contact lenses, Bausch & Lomb has seen a need to

ramp up its production. To do so, Bausch & Lomb is in the process of building new fully

automated production lines. To ensure every product meets their high quality standards,

lens measurements, including center thickness, are conducted as part of the production

process. The team has been requested to research and evaluate methods and devices

available to perform an automated, non-contact central thickness measurement. Based on

the teams technical and cost benefit evaluations of the methods/devices available, the

design team will build an offline station to functionally test the capabilities of the

measurement system(s) chosen.

Figure 1.0 – Process flow for contact lens production

1.1 Background

The center thickness of the contact lens is critical to maintain the correct optical

properties as well as to ensure comfort for the consumer. If the lens is too thin it will not

perform properly and may rip. If the lens is too thick, the optical properties will be

compromised and the consumer will not be comfortable wearing the lens. Therefore,

verifying that the product has the proper center thickness is critical to maintain the

product integrity.

5 2/18/2005


1.1.1 Current Measurement Method

Bausch & Lomb currently performs this lens central thickness measurement on a

manual offline station, which mechanically contacts the lens to perform the measurement.

The lens is in the wet state at the time of measurement. After the measurement has been

made, the lens must be discarded as the mechanical contact that the measurement device

makes with the lens may impose defects on the surface of the lens. Since lenses must be

thrown out after the current measurement is performed, lens central thickness is

monitored at an audit level of between 1 and 1.5 percent, rather than at 100 Percent of

Lenses Made (PLM).

1.1.2 Desired Method

Bausch & Lomb would like the design team to develop an automated, non-contact

measurement system for numerous reasons. A non-contact method would allow B&L to

measure the central thickness without discarding product. Since no contact would be

made with the lens surface, there would be no possibility of damaging the surface of the

lens. The automated system would also lower production costs and increase quality. The

system would not require an operator, so the non-value added labor cost would be

decreased substantially. A non-contact device would allow B&L to measure every lens’s

central thickness, which would insure a higher quality product.

1.1.3 Possible Points of Integration

In order to reduce costs further we will also determine the manufacturing process

step at which it is best to perform the central thickness measurement. During the

6 2/18/2005


manufacturing process the lens is either in the dry state or the wet state. In the dry state,

there are three scenarios where the lens central thickness can be measured, including:

while both mold halves are still assembled, after the mold has been de-capped, and after

the lens has been released from the mold. Since the lens starts off in the dry state, it

would be beneficial to perform the measurement at some point during the dry stage, as it

would allow bad product to be discarded at an earlier stage of production.

In the wet state, the lens can be measured in either the final blister or the wet cell

used for cosmetic inspection. Although we do not see inspecting in the blister as a cost-

effective method, we will keep it as a possible point of integration in case a measurement

cannot be performed elsewhere in the process.

As part of our development process, we will consider each of the scenarios

mentioned above, and evaluate the pros and cons of each. We will attempt to find

systems capable of measuring in more than one of the process steps above.

1.2 Confidentiality and Protection of Intellectual Property

Given the highly competitive nature of the contact lens manufacturing industry,

Bausch & Lomb has required that a Bausch & Lomb representative, prior to its public

release, review all information disclosed in any publication regarding this project. With

that being said, it is to be understood that certain portions of this report may not contain

all information that was discovered during the research and concept development phases

of this design project.

7 2/18/2005


2.0 Needs Assessment

2.1 Needs Assessment Overview

In performing a needs assessment for this project, the team in cooperation with

Bausch & Lomb representatives outlined and agreed to the requirements of the

Automated Lens Measurement System. With these requirements an overall mission

statement was formed along with team goals and objectives. The team then broke up the

member roles and responsibilities.

2.2 Requirements – Measurements

The first requirements specify the thickness range to be measured. The range for

this project is 50 – 250 μm. As a frame of reference, a typical human hair is

approximately 50 μm and standard sheet of 8.5 x 11 printer paper is approximately 185

μm. The thickness requirement is born out of the need to measure different products such

as single power correction, multifocal correction or toric lenses and their range of Stock

Keeping Units (SKU’s).

The tolerance specified for the measurement is ±10 μm. This requirement is

based around the optical properties of the lens and the comfort realized by the consumer.

Since these characteristics are directly related to its center thickness, the specified

tolerance must be held.

A gauge repeatability and reproducibility less than 18% is also required. This is a

Bausch & Lomb quality requirement, which insures both precision and accuracy of the

measurement are maintained at an acceptable level.

8 2/18/2005


The measurement area of the system is not to exceed 1.0 square mm. This is due

to the lens geometry, specifically the anterior and posterior curvatures as well as the

thickness profile across the lens. A limit of 1.0 square mm holds the measurement to the

central point of the lens.

2.2.1 Non-Contact

Bausch & Lomb stressed the non-contact requirement from the beginning. It has

greatly impacted the project by increasing both complication of making the measurement

and cost. This requirement is a quality/yield based. The word contact is similar to bump,

crash, jolt and strike as found in a thesaurus. This is undesirable from a quality

standpoint, regardless of how gentle the contact is. The underlying theme remains the

same, the more lens handling, and the more chances there are for cosmetic defects to

occur. Lenses are extremely brittle and easily subject to cosmetic defects in the dry state.

While the lens is more durable in the wet state, there is still a possibility of causing

cosmetic defects.

There also exists the possibility of causing a mark on the lens visible to process

machine vision systems. These systems are trained to find actual defects on lenses and

are antagonized by non-defect process signatures, which appear similar to actual cosmetic

defects. Elimination of a contact method further limits the possibility of false rejects at

the inspection point.

9 2/18/2005


2.2.2 Integration

The end goal of the project is to have a fully functional standalone test station,

similar to the current station used by operators. Bausch & Lomb does not expect and is

not requiring the team to integrate the new process into any of its current manufacturing

lines due to the implications and complications of doing such. However, Bausch &

Lomb is requiring that the system be designed with integration and extensibility in mind.

To accomplish this goal, the team is requiring the system to meet the current

shortest cycle time of Bausch & Lomb’s manufacturing line with the intent to measure

every lens. Design of the standalone test station will be focused around the point of

integration on the manufacturing line. Design for manufacturing will be implemented in

designing the system such that as many common parts as possible will exist between the

test station and the integrated system.

As required by Bausch & Lomb, a plan for line integration will be provided. The

plan will include all drawings, part numbers, instructions and bill of materials needed to

integrate and implement a fully functional system.

2.2.3 PLC Interface

With lot integrity and line integration in mind, the system must be able to

communicate to a Programmable Logic Controller (PLC). A PLC interface will allow

Bausch & Lomb to record line data for process control, development and improvement.

10 2/18/2005


2.2.4 User Interface

On both the standalone test station and the proposed integrated solution a user

interface is required. This requirement will allow the test station operator to view and

record the last measurement made. On the integrated solution, a user interface will allow

the line operator to aide in monitoring the process. The user interface will also allow line

technicians to easily set up and calibrate the system.

2.2.5 Extensibility / Flexibility

While it is impossible for Bausch & Lomb to know what the characteristics of

future products will be, it is requiring that the system be extensible and flexible enough to

process these new products. Possible influences could be the tint/opaqueness of the lens,

the monomer used, different molding materials and new lens geometry. It is impossible

for the team to guarantee this requirement can be satisfied indefinitely, but the team will

focus on this requirement when evaluating technologies. It is realistic that the team can

satisfy this requirement within the designed lifespan of the system.

2.3 Mission Statement

With a high level view of the project in mind, the team agreed on the following

mission statement:

“To provide Bausch & Lomb with the most cost effective non contact solution for

accurately measuring the central thickness of a contact lens.”

The team would like to focus on meeting the requirements with the most cost

effective solution possible. Certainly a low cost system may give up some of the

11 2/18/2005


flexibility desired by Bausch & Lomb and a high-end system may satisfy and exceed all

requirements. The team would like to find the best overall solution, as expressed in the

mission statement.

2.4 Goals & Objectives

Besides meeting the requirements set forth by Bausch & Lomb, the team

developed goals and objectives to help provide them with the best overall solution.

The first goal of the team was to research all non-contact methods for thickness

measurements. After researching various technologies, the team evaluated the pros and

cons as applicable to a make vs. buy solution within the given constraints.

As stated in the mission statement, the system should be cost effective. This will

allow Bausch & Lomb to justifiably integrate the system into its manufacturing lines.

The system, and more specifically the device used to measure the central

thickness should have customer support as needed. In the event that a solution with

highly developed components and/or software is implemented, the team wants Bausch &

Lomb to have the best resources possible for using the system.

The team will also design any and all needed fixturing. As part of the design

process and project budget, the team will design as much of the system as reasonably

possible.

2.5 Team Charter

The team established guidelines on how to best conduct business in the most

efficient manner possible while promoting involvement from all team members. Team

12 2/18/2005


members are expected to attend and be on time to all meetings or have a reasonable

exception. Members will be respectful of each other and of all ideas. Constructive

criticism will be used at all times. Meeting minutes will be emailed out by midnight of

the next day. The next tentative meeting will be announced at the end of each meeting.

Assignments will be completed on time. In the event that an emergency arises or

an assignment cannot be completed on time, the group member will notify the team so

that proper arrangements can be made.

Emails will be responded to within 24 hours or by assigned date. Team members

will print out emails to aide in documenting the project. The team charter is a living

document subject to amendment upon ratification of all team members.

2.6 Constraints

This project is faced with many constraints, which will influence the overall

success of the project. After doing some initial research, the team decided to perform a

make vs. buy rational analysis.

In performing this analysis, the team came to the realization that the optimum

solution would be to integrate a developed technology into a system rather than attempt

to reinvent the wheel. This decision was influenced by many factors.

The first limiting factors are the timeline, whereby the project needs to be finished

by early/mid May 2005 and the size/experience of the team. The team is neither large

enough nor proportioned correctly with its knowledge base to develop a non-contact

solution accurate to the micron range.

13 2/18/2005


Requirements set down by Bausch & Lomb leave a narrow margin of

technologies capable of performing the measurement. To develop a laser, spectrometer

or ultrasonic technology to a level of sophistication to meet Bausch & Lomb’s

requirements is unrealistic.

Furthermore, while patent searches did not reveal much prohibiting their use in

the contact lens thickness measurement application, there exists numerous patents around

the individual technologies themselves. This barrier alone would have greatly slowed

down or stopped the project, had the team opted to design a solution.

By deciding to integrate a purchased solution, the team has been and will continue

to be constrained by vendors. Before going into too much detail with vendors,

confidentiality agreements need to be established. This process has consumed

approximately forty percent of Senior Design I. This has impacted the project further do

to the constraints on lead times for sample reports. The ripple effect produced by this

will delay final decisions as to which vendors should be tested in house first. Delays in

designing and ordering fixturing are also expected.

Fixturing constraints exist due to the fine tolerances needed. Lenses will need to

be located with extreme accuracy and repeatability to meet requirements. As a result, a

Bausch & Lomb approved machine shop will be contracted to manufacture the fixturing

designed by the team.

Bausch & Lomb has agreed to support the team with the process development

personnel and resources it has. Due to the number of projects and involvement in these,

the team may be constrained by the timing and amount of available support.

14 2/18/2005


While the team is sufficiently funded, budgetary constraints also exist. The team

will need to manage funds to be able purchase fixturing and pay for trial lease periods of

systems.

2.7 Risk Assessment

The requirements propose the greatest risk to the project. An initial bin of

vendors was quickly narrowed down because they did not feel they could perform. Due

to the arrangement of the senior design project and graduation of team members, there

exists a hard deadline by which all work must be completed. Any delays pose a risk to

the entire project. This has lead the team to pursue a very aggressive schedule in hopes

of having time for a couple delays which will surely occur. All lead times present a risk

to the team. Future risks for the team include finding the most suitable vendor, being

able to design and obtain fixturing for the system, producing a fully functional test station

and publishing an integration plan. The project is being worked on in a parallel fashion

whenever possible to mitigate the risk of missing deadlines.

2.8 Budget

Bausch & Lomb is sufficiently funding the project to achieve success. With a

well-managed budget, the team will be able to purchase fixturing and bring systems in

house on lease or demo for full evaluation. The responsibility to allocate funding and

purchase a complete system will rest with Bausch & Lomb.

15 2/18/2005


3.0 Concept Research

3.1 Possible Technologies and Discounted Technologies

This section will outline the various concepts that have been researched.

3.1.1 Capacitance Method

The capacitance method utilizes a parallel plate capacitor by inserting the material

to be measured between the plates to act as a dielectric. The material will change the

voltage characteristics of the capacitor. As long as the material properties of the lens are

known, a correlation can be found between the voltage characteristics and the thickness

of the lens. The lens must be characterized with known thicknesses to create a look up

table as a reference for the device.

Advantages of the Capacitance Method:

The accuracy of this method tends to be very high.

Disadvantages of the Capacitance Method:

The operating distance of the plates may be too close to fit a curved material. The lenses must be characterized with known thicknesses. This may prove

difficult without destroying the lens. The lens must be positioned exactly perpendicular to the plates of the capacitor. The plates of the capacitor must be fixed which would complicate the positioning

of the lens. It would be impossible to measure the lens in the mold with this method. The effects of a curved material inside of a capacitor are unknown.

16 2/18/2005


3.1.2 Laser Triangulation

The laser triangulation method uses a laser source oriented at an angle to the lens.

The laser both reflects off of the top surface and travels through to the bottom surface of

the lens where it is reflected for a second time. A laser sensor is situated opposite of the

laser source. This sensor is able to detect the reflection of the laser from both the top and

bottom surface of the lens. Data is passed to a software system that can measure the

thickness of the lens based on the refractive index of the material as well as the distance

between the two laser signals.

Advantages of Laser Triangulation Method:

Only one measurement of the lens is required. The accuracy of the systems is very high. Measurements can be done both in and out of mold. Sensor and receiver are very compact. Systems are relatively inexpensive.

Disadvantages of Laser Triangulation Method:

May be difficult for laser to find surface of lens. Measurement time may be too long because of high accuracy. Refractive index may not be constant on some lenses.

3.1.3 Optical Spectrometer

The optical spectrometer method uses a multi-chromatic light source oriented

perpendicular to the lens. The light source reflects off of the top surface and travels

through to the bottom surface of the lens where it is reflected for a second time. The

reflected light is fed into a spectrometer where the wavelengths of light are separated.

Light bands of a certain wavelength will appear that relate to the top and bottom surface

17 2/18/2005


reflection. The software system can measure the thickness of the lens based on the

refractive index of the material as well as the wavelengths that have been returned from

the lens.

Advantages of Optical Spectrometer:

Only one measurement of the lens is required. The accuracy of the systems is very high. Measurements can theoretically be done both in and out of mold. Sensor and receiver are very compact. Vendor is very confident based on past experience.

Disadvantages of Optical Spectrometer:

May be difficult for Optical Spectrometer to find surface of lens. Characterization of angularity tolerance may be difficult

3.1.4 Laser (Autofocus)

The autofocus laser method uses a laser and lens system similar to a DVD player

in that it measures the distance from the sensor to a reflective surface. The distance to the

top surface is subtracted from the distance to the bottom surface to obtain a thickness.

This data must be manipulated manually because neither the software nor the hardware

was designed for thickness measurements. These systems are also designed for highly

reflective surfaces.

Advantages of Autofocus Laser:

The accuracy of the systems is very high. Measurements can theoretically be done both in and out of mold. Sensor and receiver are very compact.

18 2/18/2005


Disadvantages of Autofocus Laser:

Reflectivity of lens may not be enough for sensor to find both top and bottom surfaces.

Two measurements are required. System not designed for thickness measurements. Z-axis movement of either lens or sensor may cause system to be outside of

tolerance. Z-axis movement may drive up cost of system.

3.1.5 Ultrasonic

The ultrasonic system is similar to a sonar system that uses a high frequency

transducer to map the position and surfaces of the lens. This system requires exact

positioning of the lens in a wet environment. The ultrasonic system that we are

considering was designed and built with contact lenses in mind, although it has never

been used in an automated setting. The system is being considered as a wet alternative to

the dry systems.

Advantages of an Ultrasonic system:

The accuracy of the systems is very high. System designed and built for contact lenses.

Disadvantages of an Ultrasonic system:

Not currently used in an automated setting. Measurement required in a wet environment, which is not desired by

Bausch & Lomb. Difficult to implement across all manufacturing platforms. High frequency transducer may drive up cost of system.

19 2/18/2005


3.1.6 Vision System

The vision system uses a high-resolution camera to take a digital picture of each

lens. The picture is then analyzed by a computer to determine the thickness of the lens

based on the number of pixels that the lens occupies. The accuracy of this system is

dependant on the quality of the camera that is being used to photograph the lenses. This

system is similar to the current vision system.

Advantages of Vision System:

Similar to current utilized technology.

Disadvantages of the Vision System:

Software intensive system. Camera may not be able to see profile of lens. High quality camera may drive up cost of system. May be difficult to accurately photograph the lens while in the mold or mold half. The sensor (camera) may be large.

3.1.7 Mechanical Contact System

The mechanical contact method involves automating the current procedure for

measuring the central thickness of the lens. Lowering a probe onto the lens that is resting

on a pedestal does this. The current procedure is done in the wet state on an offline

manual station and is performed by a technician. This system is used on an audit basis

and the lenses must be destroyed after being measured.

Advantages of mechanical contact system:

The optical properties of the lens will not affect the system.

20 2/18/2005


The function and accuracy of this system are already known with respect to the

manual station.

Disadvantages of mechanical contact system:

Every lens cannot be tested because of quality issues.

Bausch & Lomb has specified a non-contact system.

This method has not been attempted in the dry state.

This method cannot be done in the mold or half mold.

3.2 Long List/Sources

After the initial needs assessment, research was done to gather companies and

technologies that were available and could handle measuring the contact lens to Bausch

& Lomb’s specifications. Individual Internet research was completed and compiled.

Several sources were used such as Google, Thomas Registrar, Global Spec., and Bausch

&Lomb Experts. The companies that were discovered consists of: Lumetrics, Keyence,

Elektrophysik, FRT of America, Mission Peak Optics, Micro-Photonics, Filmetrics,

Thermo Electron Corp., ABB, Adetech, Onosokki, MTI Instruments Inc., LMI

Technologies, Micro-Epsilon, Beta Laser Mike, ORYX, Panametrics, AccuSentry,

Norman N. Axelrod and Associates, Dr. Schenk Inspection Systems, Optical Data

Associates, LLC., and Solve TECH Inc. The companies offered a wide range of

technologies that were discussed in section 3.1.

21 2/18/2005


3.3 Short List

Researched companies were contacted to obtain a technical representative to

initially assess if it was feasible for the company to handle the given application. In

addition, to obtain recommendations on which device(s) would be the best to use. After

the initial screening the long company list developed into the following short list:

Lumetrics (Low Coherence Intferometry) Mission Peak Optics (Optical Gauge) Filmetrics (Spectrometer) MTI Instruments (Fotonic Sensor/Triangulation Laser) LMI Technologies (Triangulation Laser) Micro-Epsilon (Spectrometer/Polychromatic White Light) ORYX (Optical Gauge) Panametrics (High Frequency Ultrasonics)

3.4 Reasons Not to Pursue Certain Companies

The companies that did not make the short list had several reasons as to why they

would not be able to handle the application of measuring the central thickness of a

contact lens.

Beta Laser Mike had a device that consisted of a transmit and receive laser. The

Focal diameter would be too big for the application. This type of device is only good for

flat applications.

FRT of America was not able to handle the application either. They were not

confident they could measure a curved surface such as a contact lens. Micro-Photonics

could only measure up to a maximum of 50 microns.

SolveTech’s capacitive method would require a much larger spot size than

required (>1mm). Also, a fixture would need to be developed to position the lens

accurately between two plates with a separation distance significantly smaller than the

22 2/18/2005


overall height of the lens. The method's accuracy was also questionable for the given

application.

Keyence’s device was incapable of measuring the size and accuracy needed.

AccuSentry’s technology is essentially a camera or vision system that is used to inspect

products. The entire concept of a vision system was discarded due to the current lack in

adequate technology. Norman N. Axelrod and Associates was not pursued any further

because they do not sell a specific technology. Instead they would come in, analyze the

problem, and custom develop a solution. In this case, it would defeat the purpose of

Senior Design.

Dr. Schenk Inspection Systems sell products to measure thin films. Meaning, that

all of their products are meant to be installed on a high speed manufacturing line and take

a measurement based on the profile view of the thin film. Due to those characteristics

this was not a viable technology to pursue. Optical Data Associates, LLC is a small

testing company that specializes in high precision inspection of various components for

their optical properties and so forth. This company is just a testing firm and therefore

would not be able to help or sell any technology that would meet the needs of the

application.

Onosokki is only in the business of contact method systems for measurement and

this would not meet the applications requirement of a non-contact method requested by

Bausch & Lomb.

Adtech, ABB and Thermoelectron were all companies researched, but no

response was ever heard from them. Therefore, they were not looked into any further.

23 2/18/2005


3.5 Method for Gathering Technology and Company Information

A teleconference or onsite visit was scheduled with each of the resulting

companies. An on-site visit to Lumetrics occurred on Tuesday (1/11/05). The remaining

companies had teleconferences with the team on Wednesday (1/12/05) and Friday

(1/14/05). The information gathered from each company was the device measurement

range, measurement tolerance, angularity tolerance, spot size, number of measurements

required, device output, cycle time, system cost, device model number, working height,

lens state for measurement, sensor/controller ratio, sample lead time, demo lead time,

length of demo period, and system lead time. After all the information was collected

each team member revised their notes and created a list of their top company choices.

3.6 Patent Search

Several patents were found that are within the realm of the given application. The

topics varied from a contact probe that measured the actual thickness of a contact lens, to

automated visual inspections of a contact lens. Since the application that is being dealt

with is more process oriented on the measurement of the central thickness of a contact

lens, the patents listed below are not being infringed upon by our application. Each will

be discussed in further detail as to why they do not impact our project. Please see

Appendix A to view all patent abstracts for further reference.

4,665,624 4,403,420 5,205,076 6,134,342 6,765,661 6,301,005 6,490,028 6,847,458

24 2/18/2005


6,822,745 6,815,947 6,791,691 6,775,003 6,791,696

3.6.1 Patent Information

Patent number 4,665,624 deals with a soft contact lens analyzing apparatus. This

apparatus utilizes a fixturing device and several measurement scales to determine the

diameter, sagittal depth and central thickness of a contact lens. All of the scales use

probes that must come into contact with the actual lens. Therefore this describes a

mechanical, contact system which is not what our application calls for.

Patent number 4,403,420 is about a digital gauge for measuring the sagittal depth

and thickness of a lens, and the related systems and methods to do so. This method

involves a fixture and several linear encoders to measure the diameter, sagittal depth and

central thickness of a lens. Each of the encoders is connected to some type of probe that

needs to come into contact with the lens. Again, this is a mechanical contact system in

which our application will not infringe on.

Patent number 6,134,342 talks about a visual inspection method and apparatus for

a contact lens. The method described is automated. The visual inspection system is

looking for defects such as foreign material, scratches, breakage and so forth. The actual

system does not perform any quantitative dimensional measurements and therefore does

not have to do with our application.

Patent number 5,206,076 is for a self aligned manufacturing system and method.

This method does not pertain to the metrology of contact lenses. It describes a method on

25 2/18/2005


how to actually produce contact and intra-ocular lenses. Since this is describing the

manufacturing process and not a measurement process our application does not conflict.

Patent number 6,765,661 describes a lens (such as contact lens) inspection

method. This system looks for such flaws as tears or surface defects. Again, this system

does not perform any quantitative dimensional measurements and therefore our

application will not infringe with this patent.

Patent number 6,301,005 deals with an inspection system for optical components.

This system contains a device to hold the optical component in place. Also, it has the

means to inspect the optical component for any apparent defects. Given that this system

does not take into account quantitative dimensional measurements the compared

application is not the same and will not infringe.

Patent number 6,490,028 is for a variable pitch grating diffraction range finding

system. What is described is a very precise method to determine the range or distance

from a reference point to an object. Utilizing a variable pitch grating achieves this high

precision. This system uses a completely different methodology than any of the

apparatuses the team has evaluated for the given application.

Patent number 6,847,458 refers to a method and apparatus for measuring the

shape and thickness variation of polished opaque plates. In this system dual

interferometers are used. One is placed on each side of the plate to perform its surface

mapping and other calculations. Since the system is attempting to measure opaque plates

two interferometers must be used. This system is different from any of the researched

systems that have been evaluated because it is a dual interferometer system. All of the

26 2/18/2005


systems researched use only one interferometer. Also, this is for measuring opaque

substances, as our application is to measure optically clear lenses.

Patent number 6,822,745 talks about optical systems for measuring form and

geometric dimensions of precision engineered parts. This patent does describe a similar

technology that we will be utilizing. However, it describes the specific equipment and

not the overall process of the measurement. Whichever piece of equipment is chosen to

be used in our application should be protected by that respective company’s patent. No

process issues are present that would violate this patent.

Patent number 6,815,947 deals with a method and system for thickness

measurements of thin conductive layers. This system utilizes an electrically conductive

method known as eddy current. Extremely thin films that also have conductive properties

are the only applicable item that may be measured using this system. Due to its

limitations, the team ruled out this technology initially. None of the systems being

evaluated use this or any related technology.

Patent number 6,791,691 refers to a measuring method that uses attenuation in

total reflection. This patent describes a similar technology that we will be utilizing.

Furthermore, it describes the specific equipment and not the overall process of measuring

the object. That respective companies patent should protect whichever piece of

equipment the team decides to use in our application. No process issues are present.

Patent number 6,775,003 is about an apparatus and method for total internal

reflection spectroscopy. This also describes a similar technology that is being evaluated.

Again, although it has a similar technology it does not describe the process. Therefore,

27 2/18/2005


the researched technologies respective companies patent should protect the equipment in

the end that the team decides to put into use. No process issues are present.

Patent number 6,791,696 talks about an automated optical measurement apparatus

and method. This patent describes the method to measure lens properties, such as central

thickness, utilizing a wave front analysis. None of the technologies researched involve

this type of technology. For this reason, our application will not infringe on this patent.

3.7 Product Specification Research

This section highlights how the characteristics of a contact lens were researched

and captured.

3.7.1 Contact Lens Quick Reference Guide

Research was completed to create a reference guide for Bausch & Lomb’s contact

lens specifications. The specifications include product line, lens type, monomer,

diameter and tolerance of the lenses, wet central thickness range and tolerance of the

lenses, sagittal depth range and tolerance of the lenses, power range of each lens,

refractive index of each lens, if the lens had tint, and the document number of the

Finished Product (FP) specification. This guide was referred to when vendors were

contacted. Due to proprietary information this chart cannot be appended.

28 2/18/2005


3.7.2 Radius of curvature

During research the radius of curvature (base curve) was questioned by some of

the vendors as this could potentially pose a problem in obtaining the central thickness

measurement. This is another area where experts at Bausch & Lomb were able to inform

the team of the dimension. This dimension varies across all product lines. Due to

proprietary information this dimensional information cannot be released.

3.7.3 Mold Information

During the early stages of the project the mold material was introduced as

Polypropylene and PVC depending on which contact lens it will contain. The theoretical

refractive index of the materials are known, however the actual refractive index of the

molds is unknown. This is confidential information that cannot be disclosed.

3.7.4 Cost Research

Research was done to identify what the overall cost is to actually manufacture a

contact lens. Cost was broken down by each stage of the lens manufacturing process.

Also, the cost of material and operator labor and benefits were gathered. If the apparatus

was eventually integrated into the line as an automated system, in order to cost justify the

equipment, such costs would need to be known. This material will be covered further in

section 6.0.

29 2/18/2005


3.7.5 Centration of Lens

In order to properly present the lens to the sensor, and to take the various lens

profiles into account, a centration requirement was determined. If the measurement spot

size is less than 50 microns in diameter, than the measurement must be offset at a

distance from center equal to spot diameter plus 10 microns, in both the x and y

directions. If the spot size is larger than 50 microns in diameter, the measurement can be

taken directly in the center of the lens, at a distance of +/- 500 microns in either the x or y

direction.

30 2/18/2005


4.0 Feasibility

This section outlines how the team determined the feasibility of the companies,

and their respective technologies.

4.1 The Short List Revisited

Once the companies were eliminated due to their inability to meet the

requirements of the project, the team was left with eight companies to evaluate. Again,

these companies were:

Lumetrics Panametrics – NDT MTI ORYX Mission Peak Optics Micro-Epsilon LMI Filmetrics

All of these companies seemed capable of meeting the project requirements. The

team also had a good feel for the true potential of each company. After such extensive

research and learning from various technology experts, the team had a solid

understanding of the technical details to make effective decisions. With this knowledge,

the team had an idea of the top three companies that should be evaluated, but that idea

needed to be confirmed with evidence. Constructing a Feasibility Matrix did this. Please

see Appendix B for the complete matrix.

31 2/18/2005


4.2 Judging Criteria

The criteria by which the remaining companies would be evaluated were

determined by the project requirements (Appendix C). The primary technical criterion

was determined, but there was additional information the team felt was important that

should be included. While this data would not be scored, it was still listed on the

Feasibility Matrix for reference and to keep in mind when evaluating the companies. The

criterion is listed below:

Technical Criteria (Scored) Informational Criteria (Not Scored)

Measurement Range Device Model Number

Measurement Tolerance Working Height

Angularity Tolerance Lens State for Measurement

Spot Size Sensor/Controller Ratio

Number of Measurements Required Sample Lead Time

Device Output Demo Lead Time

Cycle Time Length of Demo Period

System Cost System Lead Time

Team Opinion

Table 1.0 Technical and Informational Criteria for the Feasibility Matrix

4.3 Weighting Criteria

Once the technical criterion that the companies would be evaluated for was

identified, it was necessary to weight the criteria. The criterion must be weighted

because some are more important than others. The most important criterion would have a

weight of five, and the least important criterion would have a weight of one. No criteria

32 2/18/2005


were given a weight of one, and the majority had a weight of five. The reason for this is

that there are multiple critical factors that the systems must be able to meet in order to

work effectively. The criterion that was slightly less important was given weights of four

and three.

4.4 Scoring

Once the companies, criterion, and weight were all identified the scoring could begin.

This was done with a fairly simple system outlined below:

Companies received a score of 1 if they might be close to meeting the requirements, but it would require some additional engineering to get the system to be able to achieve that specific criterion.

Companies received a score of 2 if they met the requirements. Companies received a score of 3 if they exceeded the requirements.

Two examples of the scoring system are outlined below:

System Cost Scoring Device Output Scoring

If the system cost more than $10,000, the

company received a 1.

If the system had an analog output, the


If the system cost $10,000, the company

received a 2.

If the system had a digital output, the


If the system cost less than $10,000, the


If the system had a digital output and some

type of software bundle, the company

received a 3.

Table 2.0 Technical and Informational Criteria for the Feasibility Matrix

33 2/18/2005


These scores were then multiplied by the respective criterion weight and summed

to find the overall score for each company. The top three scores then identified the best

three companies and technologies that are able to successfully meet the projects needs.

4.5 Sample Test Results

Samples of contact lenses in three different states were sent to all vendors to

evaluate. The rationale was that this would once again confirm the teams’ decisions and

insure that all of the decisions being made were sound. Please note that LMI would not

evaluate samples, so there is no report from them. Please also note that all vendors

(except Panametrics – NDT) were given contact lenses still sealed in the mold, contact

lenses in the mold but decapped and dry contact lenses. Panametrics – NDT was given

wet contact lenses in solution to evaluate. Below is a summary of the testing results from

each vendor. The full reports can be found in Appendix D.

Lumetrics

Lumetrics conducted a sample analysis of the contact lens in various states and

evaluated the systems ability to accurately and repeatedly measure the center thickness.

Since they could measure the lens in the wet state, in addition to dry, it is easy to compare

the results they provide to the results acquired from the same lens using the current

manual process. For all trials conducted, their results had excellent agreement with the

current process.

34 2/18/2005


MTI

The technology utilized by MTI is only able to measure the lens in the dry state.

The team has not received an official report from them, but has conversed with their

representative on multiple occasions. The general consensus so far seems to be that they

are not able to achieve repeatable results with any of their systems. They are however

continuing their attempts and the team is moving forward while awaiting the data from

them.

ORYX

The team has not received an official report from ORYX. The preliminary results

given via e-mail and phone calls show that they are able to measure the lens in any of the

various dry states. The only issue that they may have is the cycle time requirement, since

their sensor takes longer than any other to acquire the returned signal and calculate the

thickness. The team feels comfortable with what ORYX is capable of and is awaiting

their final report.

Panametrics – NDT

Panametrics measures the lens in the wet state only due to their ultrasonic

technology. Therefore, it is very easy for the team to confirm their results and see how

well they relate to the current process. All of the results show excellent agreeability with

the current process. All measurements from Panametrics were verified to be within two

microns when the same lens was measured with the current manual station.

35 2/18/2005


Micro-Epsilon

The team does not have an official test report from Micro-Epsilon, but the vendor

has come and performed a demonstration. This demonstration showed their technology

and how it works, and they were able to accurately measure several lenses in the various

dry states. These initial demonstration measurements show good compatibility with

results acquired from the current process.

Mission Peak Optics

Mission Peak Optics was only able to measure the dry lens in its free state. Their

report was quickly returned to the team within one day of receiving the samples. The

results from their testing look promising and have good agreement when compared to the

current process.

4.6 The Top Three

The top three companies identified by the matrix confirmed the teams’ opinion on

what the best companies were. The three companies are:

Lumetrics

Micro-Epsilon

Panametrics

These three companies will have their units brought in house to Bausch & Lomb for the

team to do extensive testing on the units. The team will determine these units’ abilities to

meet the projects needs and will make a final recommendation to Bausch & Lomb from

these companies.

36 2/18/2005

Figure 2.0 Light Reflections bounced back to the DI 330 OPTIGAUGE for a single-layer film and a two-layer film with adhesive.


5.0 Designs

This section outlines the designs of the vendors, as well as our preliminary design

and placement plan. Additional information from each company’s website can be found

in Appendix E.

5.1 Lumetrics

The DI 330 OPTIGAUGE FILM THICKNESS MEASUREMENT SYSTEM

employs advanced optical technology originally developed by Eastman Kodak to monitor

its polyester film manufacturing operation for thickness uniformity. The DI 330 system

operates using the principle that light incident on a translucent film will reflect a portion

of that light. In fact, a reflection will occur at every surface interface. So, a single-layer

film will have two reflections, one from the upper surface

(R1) and one from the lower surface (R2). A two-layer film

with an adhesive in-between will have four reflections; one

from the upper surface (R1), one from the first layer-

adhesive interface (R2), one from the second layer-

adhesive interface (R3), and finally one from the lower

surface (R4).

The different reflections carry information about layer

thickness based upon the distance that the reflections have

traveled. Using advanced digital processing and proprietary

software, the DI 330 OPTIGAUGE system analyzes each

reflection and then calculates the exact thickness of each

layer.

37 2/18/2005


Features of DI 330 OPTIGAUGE

Reduce maintenance expenses with unique optical technology that is non-toxic, and non-radioactive.

Decrease inspection costs and scrap with non-contact, non-destructive gauging system

Improve customer satisfaction and profits through the highest guaranteed accuracy of ± 0.1 micron (± 0.004 mil)

Decrease scrap costs with instantaneous feedback and a measurement rate of 30 Hz

Lower inspection costs with a wide range of measurement from 12 microns to 9 mm

Decrease inspection time with simultaneous measurement of multiple layers Flexible system measures specialty multi-layer films, medical packaging,

adhesives and laminates Portable enough to inspect and measure lenses, flats, assemblies, ball lenses

with no system changes Works with a multitude of solids, liquids and coatings

The DI 330 OPTIGAUGE seems to be the most versatile sensor of our final three.

It is able to measure with both halves still on the lens, as well as with the bottom half of

the mold still attached to the lens, and the freestanding lens. Of course we would like to

place the sensor as far up the line as we can. The optimum place for this sensor would be

immediately after the monomer that makes up the lens has set into its solid form. This

takes place after the lens has gone through an Ultraviolet (UV) curing process.

38 2/18/2005


The lenses are placed in a single file on a conveyer after the UV cure process.

This position in the line would allow the sensor to measure before the top of the mold has

been removed. The size of the sensor should not be a problem if it is placed before the

machine that removes the top of the mold.

5.2 Micro-Epsilon

optoNCDT 2400 is a confocal displacement sensor for extremely precise

applications. Polychromatic light (white light) is focused onto the target surface by a

multi-lens optical system. The lenses are arranged such that the light is broken down into

monochromatic spectra by controlled chromatic deviation. A certain distance is assigned

to each wavelength by a factory calibration. The light reflected from the target surface is

passed via an optical arrangement to the receiver optical system, which detects and

processes the spectral changes.

39 2/18/2005

Figure 2.1 - Casting Machine: The lenses exit the UV curing stage of the casting machine and are in their solid state for the first time.


Figure 3.0 optoNCDT 2400: In-Focus Displacement and Position Measurement

Characteristics

Measuring principle: Confocal Measuring range: 0.08/0,35/1/3/10/24 mm0.003/0.014/0.039/0.118/0.39/0.94 inch Linearity: ±0.1 % FSO (full scale output) Resolution: 0.004 % FSO Measuring rate (selectable): 30/10/300/1000 Hz

Applications

Figure 3.1 Thickness of transparent materials

Figure 3.2 Distances to glossy and transparent surfaces

Figure 3.3 Measurements in holes (hole depth)

40 2/18/2005


Figure 3.4 Measurement of surface contours

After speaking with a representative of the company, and from the data that has been

returned to us from the testing procedure, the team has decided that there are two logical

places for the sensor.

After the top of the mold has been removed.

After the lens has been released completely from the mold

41 2/18/2005

Figure 3.5 Lens Release Machine: This machine removes the lens from the bottom half of the mold.


The optical sensor for the optoNCDT 2400 is very compact and could be

positioned in the 4-6 inch space before the mold release machine. The data collection

box can be positioned at the bottom of the machine where there is more room.

It would be more desirable to take the measurement while the lens is still in the

bottom mold half (for centering purposes). If it is found that the optoNCDT 2400 can

take more accurate measurements while the lens is completely free of the mold, then the

sensor will be implemented on one of the lens handling spindles. The picture above

shows a machine that is not surrounded by close quarters creating a good location for the

sensor and data acquisition box. This is the last place in the lens release machine that the

lenses are being processed on an individual basis. After this they are placed on the tray

shown in the picture until they are packaged.

The positioning of the lens may cause some design issues if the lens has already

been released from the mold. The mold would be easier to center and would also be

further up the line.

42 2/18/2005

Figure3.6 Lens Release Machine: The lenses pass through this section of the machine without any pieces of the mold before they are placed in the tray at the far end of the picture.


5.3 Panametrics

Panametrics-NDT 25 MULTI PLUS

ultrasonic thickness gage for multilayer

materials offers several unique

measurement capabilities. In addition to

making thickness measurements on metal,

plastic and many other materials with

varying thickness ranges, the 25 MULTI

PLUS can calculate and simultaneously

display as many as four separate

measurements. The Summation Mode accurately displays the total thickness of selected

layers.

Features of the 25 MULTI PLUS:

Calculates and simultaneously displays thickness measurements of as many as

four layers, and displays the total thickness of selected layers

Measures thickness of barrier layers in applications such as plastic fuel tanks

and bottle pre-form

A-Scan display for waveform verification

Wide thickness range: 0.004 to 20 in (0.100 to 508 mm)

Resolution up to 0.0001 in (0.001 mm)

43 2/18/2005

Figure 4.0 Panemetrics-NDT 25 MULTI PLUS


Internal alphanumeric file-based datalogger stores 18,000 thicknesses or 1,750

waveforms

The Barrier Layer Mode feature makes it possible to measure critical barrier

layers in multilayer plastic parts such as gas fuel tanks and bottle pre-forms. This special

mode displays the thickness of thin barrier layers that are typically too difficult to

measure with conventional ultrasonic thickness gages. This is because of lack of

separation between the echo from the front and back of the barrier layer.

The Panametrics sensors would require that the lens be in the wet state. While

this is not the most desirable state to measure the lens in, it may be an acceptable

alternative to the dry methods discussed in previous sections. Panametrics has disclosed

that the 25 MULTI PLUS has been used before for measuring of contact lenses in a non-

automated environment and is a proven technology for our application. Unfortunately,

there may be a problem with measuring lenses that are less than one hundred microns

thick as that is the lower limit that the device can theoretically measure. This problem

could be remedied with a higher frequency transducer. This high frequency transducer

may raise the cost of the system significantly.

Precise positioning of the lens in a wet environment would require the design of a

wet cell. Positioning inside the wet cell may also increase our cycle time. This system

would also severely limit the possible placement of the sensor on the line. The desire to

measure the lens in the dry state further up the production line is driven heavily by the

logistics of manipulating a lens in the wet state. The cost savings of doing this

measurement in the dry state in relation to the wet state is relatively small.

44 2/18/2005


6.0 Conclusion

This section will wrap up the outcome of Senior Design I, and outline the goals of

Senior Design II.

6.1 Summary

Senior Design I has focused mainly on researching technologies and devices

available. The team started with 22 companies, and narrowed the list down to 8

companies. After performing a feasibility assessment, the team was able to separate its

top three choices. With these top vendors the team plans to go on to Senior Design II and

accomplish all its goals.

6.2 Goals for Senior Design II

The final goal for Senior Design II is to present to Bausch & Lomb the teams

compiled in-house test data and final recommendations of the top units. Once the final

unit is chosen, the team plans to create a fully functional offline system. The team will

also develop an implementation plan, for Bausch & Lomb to integrate the system online.

6.3 Action Plan to Achieve Goals

The scheduling of the following action items is outlined in Appendix F. To

accomplish these goals the action plan is to start by bringing in demonstration units from

the top vendors. The team will perform a DOE and a Gauge R&R on each device to

determine if the device will meet Bausch & Lomb’s standards.

45 2/18/2005


The team plans to do a full cost benefit analysis. From preliminary calculations,

it is anticipated that all 8 of the devices from the feasibility matrix will prove to be cost

effective.

With drawings from the top three vendor units, the team plans to start designing

fixtures needed to secure the unit, as well as fixtures to correctly orient the contact lens.

From testing, the cost analysis, and all the data gathered from Senior Design I, the

team will present to Bausch & Lomb their final recommendations on each device. Once

the final system has been chosen, the team will work on creating a fully functional offline

station.

The various product lines at Bausch & Lomb will be thoroughly evaluated, and an

implementation plan will be developed to integrate a system onto the line chosen by

Bausch & Lomb. The plan will include where the device should be positioned on the

line, and how and where contact lenses that failed will be discarded. As well as how the

device will be connected to the existing PLC interface.

46 2/18/2005


7.0 References

This section gives the citation for the sources of information utilized while compiling

this report.

Global Spec 16 Jan 2005 <http://www.globalspec.com/>

Google 16 Jan. 2005 <http://www.google.com/>

Lumetrics 12 Feb. 2005 < http://lumetrics.net/>

Micro-Epsilon 12 Feb. 2005 <http://www.micro-epsilon.com/index_en.html>

Micro Format Inc. 10 Feb. 2005 <http://www.paper-paper.com/weight.html>

Mission Peak Optics 12 Feb. 2005 <http://www.missionpeakoptics.com/>

The World of Hair 10 Feb. 2005 <http://www.pg.com/science/haircare/hair_twh_141.htm>

Thomas Register 16 Jan 2005 <http://www.thomasregister.com/>

United States Patent and Trademark Office 14 Jan. 2005 <http://www.uspto.gov/patft/index.html>

47 2/18/2005

http://www.thomasregister.com/

http://www.paper-paper.com/weight.html

http://lumetrics.net/

http://www.google.com/


8.0 Appendix

Document AppendixPatent Abstracts AFeasibility Matrix BProject Requirements CVendor Testing Reports DVendor Website Literature ETimeline for Senior Design II F

48 2/18/2005


Appendix A – Patent Abstracts

49 2/18/2005


Appendix B – Feasibility Matrix

50 2/18/2005


Appendix C – Project Requirements

51 2/18/2005


Appendix D – Vendor Testing Reports

52 2/18/2005


Appendix E – Vendor Website Literature

53 2/18/2005


Appendix F – Timeline for Senior Design II

54 2/18/2005

Documents

IV - Rochester Institute of Technologyedge.rit.edu/content/OldEDGE/public/Archives/P05427/P… · Web viewThis requirement is a quality/yield based. The word contact is similar