Six Sigma Project for Improving Reaction Force

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Project Name : Black Belt Project for improving Reaction Force

Project Owner : Dipti Nayak

DMAIC

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Define

1. Map the Project2. Project Charter3. Terms and Acronyms Used4. ARMI & Communication Plan5. RASIC Model6. Details process map7. SIPOC

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Customer Sample CommentsKey Output Characteristics

Important to Customer (CTQ's)

Compressor Assy.

Area in charge

During the working of the AC cycle

improper clutching & clutch noise

observe in model-A compressor.

Improper reaction Force.

Due to improper clutching & clutch

noise customer complaints & line

rejection PPM has been increased too

much.

Customer complaints &

Line Rejection PPM.

DefineMap the Project

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In Scope: : This Project is for Compressor Model A HUB Line .

Out of Scope: All other models & Lines..

Business Case: ABC Ltd is a leading car AC manufacturing company of India & Located in Gurgaon.

Since last couple of month it has been observed that customer complaints & Line rejection PPM has been increased due to improper clutching & clutch noise in

model-A compressor .Due to which line rejection PPM has been increased & customer is very much dissatisfied

& company is also loosing revenue.

Problem Statement: It has been observed that since Jan-13 month due to improper reaction force in M-A hub assy. Customer complaints for improper clutching & clutch noise has been exceed the target 0 & reached up to 6 no's & hub assy line rejection PPM has been exceeds the target 1000 ppm & reached till 8526 ppm . Due to this repeating problem, production for the same model is hampering too much & customer is very much dissatisfied due to repeated complaints & also company is loosing their revenue & business.

Goal Statement: The goal of this project will be to eliminate the improper clutching & clutch noise problem by improving the reaction force & hence reduce the customer complaint up to the target 0 & line rejection PPM within target 1000 ppm by 20th June-13.

Project Charter

Start Date End Date

Define 10.03.13 31.03.13

Measure 1.03.13 15.04.13

Analyze 16.04.13 16.05.13

Improve 17.05.13 31.05.13

Control 1.06.13 20.06.13

High Level Project Plan

Define

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Definitions:

Indicators Definition

PPM Part per million opportunity

DPMO Defect per million opportunity

DPO Defect per opportunity

mm Millimeter

Terms and Acronyms Used Define

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Key Stakeholders Define Measure Analyze Improve Control

Sponsor- CEO A/I A/I A/I A/I A/I

Champion-SGM R/I R/I R/I R/I R/I

MBB A/I A/I A/I A/I A/I

BB M M M M M

GB M M M M M

Team Members R R R R R

Message Audience Media Who When

Project Status Leadership E-mails Black Belt Weekly Basis

Project Review GB,BB,MBB & Champion

E-mails or Meetings Black Belt As per Project Plan

Project Deliverables or Activities

Members Emails, Meetings Black Belt Weekly

When Populating the Stakeholder, consider the ARMI:• A= Approver of team decisions• R= Resource or subject matter expert (ad hoc)• M= Member of team• I= Interested Party who will need to be kept informed

Communication PlanCommunication Plan

Define

ARMI WorksheetARMI WorksheetARMI & Communication Plan

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DefineRASIC Chart

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Details Process Flow Diagram Define

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XYZ (supplier)

NA

NA

NA

NA

Hub, rivet, armature, spring plate, washer

Hub Sub, Assy

Hub Sub Assy-2

Hub Assy

Hub Assy

Hub Riveting

Hub Grinding

Reaction Force testing

Hub balancing

Slip Torque Testing

Hub Sub Assy-1

Hub Sub Assy-2

Hub Assy

Hub Assy

Hub Assy

Compressor assy. line





DefineProcess Map

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Measure

1. Data Collection Plan2. Measurement System Analysis3. Process Capability

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Y OperationalDefinition

DefectDefinition

PerformanceStandard

Specification Limit

Opportunity

Improper Reaction force

Reaction force is the load required to

deflect the hub by 0.5 mm with respect

to outer armature when load is applied

centrally on hub surface.

Sticking of Hub with Rotor due to less Reaction force.

Reaction force should lie between 90~130 N

within 0.5mm deflection.

LSL= 90N & USL=130N

10 Pcs/shift

Mode of collecting Data

Y Data Type UnitDecimal to

be Used

Data Base Container

Existing or new data

base

If New when data base would be

ready.

Plan start date for

DCP

Improper Reaction force Variable mm, Newton

Max up to three placed. Excel sheet Existing

-

-

Data Collection Plan

Equipment Used for

measurement

Equipment Calibration Information

ResponsibilityAny

Training need

Operator Information

Vernier caliper Equipment was calibrated with

Bharti automation on

dated 10.09.12.

Line QA in charge

-

-

-

-

-

Measure

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Measurement System Analysis Measure

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% Tolerance = 9.01

Number of Distinct Categories = 15.59

%Contribution

KPI Data Type

GRR% ≤ 10

NDC ≥ 5Continuous

APPRISER - A APPRISER - B APPRISER - C

CONCLUSION: As per MSA study carried out we get GRR%= 9.01 & NDC=15.59 which satisfy the AIAG Requirement (GRR% ≤ 10, NDC ≥ 5). It shows that our Measurement

System is good enough for measuring the variation of the measurement System.

13


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Measurement System Analysis

Rule Rule Description Acceptable Result

A R&R % of Tolerance <10% 9.01

B% Contribution (R&R Std deviation)

Smaller than Part-to-part variance

99.59

C Number of distinct categories >4 15.59

Overall Gage result- Measurement system is accepectable for taking measurement.

Measure

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Process Capability for current Reaction force Measure

Current process is incapable since current process potential capability & actual capability are 0.80 & 0.63 respectively & which is not acceptable as per AIAG guideline.

Current process potential performance & actual performance are 0.51 & 0.40 respectively Which is also not acceptable as per AIAG guideline.

Current process is unstable & also not in statistical control.

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Current process is not acceptable as long term process capability (ZLT) is 1.06 & short term process capability (ZST) is only 2.56 .

Current process is also unstable & also not in statistical control.

The current process PPM has been exceeds the current PPM target 1000 & has been reached till PPM 8526.31.

Z-Value & PPM for current process Measure

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MeasureDefect Pareto in Hub assy. Area During Feb-13 to April-13 Month

Six sigma project has been started to eliminate the same.

CFT is working on the same.

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MeasureModel wise defect in Hub assy. Area During Feb-13 to April-13 Month

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1. DCP for Potential Xs2. Identify Potential Xs3. DCP for Potential Xs4. Basic Analysis for Project Y5. Checking for Impact of ...... on Y6. Hypothesis Summary7. MSA results of Impacting Factors

Analyse

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Identify Potential Xs Analyse

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DCP for Potential Xs

Potential Cause Type of Data Collection Method

Test to be Used Visualization plot Used

Washer thickness Continuous Check sheet Co-relation & Regression

Scatter plot

Hub run out Continuous Check sheet Co-relation & Regression

Scatter plot

Rivet height Continuous Check sheet Co-relation & Regression

Scatter plot

Rivet dia. Continuous Check sheet Co-relation & Regression

Scatter plot

Spring plate dimple dimension

Continuous Check sheet Co-relation & Regression

Scatter plot

Flatness of hub assy. Continuous Check sheet Co-relation & Regression

Scatter plot

Grinding surface concavity


Scatter plot

Armature surface flatness


Scatter plot

Analyse

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Basic Analysis of Project YRandomness Study Randomness Study

Analyse

As per run chart we can see that process is unstable since there are clustering & trends in given data set.

P value for clustering & trend is also less than 0.05. (P value <0.05)

While P-value for Mixtures & oscillation >0.05.

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Basic Analysis of Project Y

Normality StudyNormality Study

Analyse

Anderson Darling test for reaction force shows that data is non-normal ,since data points are not falling on straight line & P-value is less than 0.05.

P-Value < 0.005 .

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Normal Graphical Plot Measure

Reaction force data is non-normal , since mean & median is not coinciding & data point is also not symmetrical about the mean & P-value is less than 0.05.

P-value < 0.005

Data variation is also too much since standard deviation is 13.05.

Central Tendency & spread studyCentral Tendency & spread study

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Basic Analysis of Project Y

Frequency distribution of Reaction force Frequency distribution of Reaction force

Analyse

Data for reaction force is not showing the central tendency & data is also showing too much variation. Some data points are also falling out side lower specification limit .

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Graphical DepictionGraphical Depiction Hypothesis Result Hypothesis Result

Inference : There is a strong positive co-relation between reaction force & washer thickness since Pearson coefficient e = 0.882 & p value is 0.000 (< 0.05) & as per Regression test R-Sq is more than 62% , Hence there is a significant impact of washer thickness on reaction force.

Inference : There is a strong positive co-relation between reaction force & washer thickness since Pearson coefficient e = 0.882 & p value is 0.000 (< 0.05) & as per Regression test R-Sq is more than 62% , Hence there is a significant impact of washer thickness on reaction force.

Checking for Impact of Washer Thickness on Reaction force Analyse

Correlations: Reaction force vs. Washer thickness

Pearson correlation of Reaction force and Washer thickness = 0.882P-Value = 0.000

Regression Test : RS = 6.19062 R-Sq = 77.7% R-Sq(adj) = 77.5%

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Checking for Impact of Dimple dimension on Reaction force Analyse

Corelations: Reaction force vs Dimple dimension

Pearson correlation of Reaction force and Dimple dimension = -0.194P-Value = 0.053

Regression Test : S = 12.8664 R-Sq = 3.8% Sq(adj) = 2.8%

Inference : Since P-Value is 0.053(>0.05) so there is no significant co-relation between reaction force & dimple dimension & as per Regression test also R-Sq is 3.8% (<62% ) ,Hence there is also no significant impact of dimple dimension on reaction force.

Inference : Since P-Value is 0.053(>0.05) so there is no significant co-relation between reaction force & dimple dimension & as per Regression test also R-Sq is 3.8% (<62% ) ,Hence there is also no significant impact of dimple dimension on reaction force.

04/14/2329


Checking for Impact of Armature flatness on Reaction force

Inference : Since P-Value is 0.095 (>0.05) so there is no significant co-relation between reaction force & armature flatness & as per Regression test also R-Sq is 2.8% (<62% ) ,Hence there is no significant impact of armature flatness, on reaction force.

Inference : Since P-Value is 0.095 (>0.05) so there is no significant co-relation between reaction force & armature flatness & as per Regression test also R-Sq is 2.8% (<62% ) ,Hence there is no significant impact of armature flatness, on reaction force.

Analyse

Correlations: Reaction force, Armature flatness

Pearson correlation of Reaction force and Armature flatness = -0.168P-Value = 0.095

Regression Test- S = 12.9286 R-Sq = 2.8% R-Sq(adj) = 1.8%

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Inference : Since P-Value is 0.115 (>0.05) so there is no significant co-relation between reaction force & flatness of hub assy & as per Regression test also R-Sq is 1.3% (<62% ) , Hence there is no significant impact of flatness of hub assy on reaction force.

Inference : Since P-Value is 0.115 (>0.05) so there is no significant co-relation between reaction force & flatness of hub assy & as per Regression test also R-Sq is 1.3% (<62% ) , Hence there is no significant impact of flatness of hub assy on reaction force.

Checking for Impact of flatness of Hub assy.on Reaction force Analyse

Correlations: Reaction force, Flatness of hub assy.

Pearson correlation of Reaction force and Flatness of hub assy. = 0.115P-Value = 0.256

Regression Test - S = 13.0284 R-Sq = 1.3% R-Sq(adj) = 0.3%

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Inference : Since P-Value is 0.469(>0.05) so there is no significant co-relation between reaction force & grinding surface concavity & as per Regression test also R-Sq is o.5 % (<62% ) , Hence there is no significant impact of grinding surface concavity of on reaction force.

Inference : Since P-Value is 0.469(>0.05) so there is no significant co-relation between reaction force & grinding surface concavity & as per Regression test also R-Sq is o.5 % (<62% ) , Hence there is no significant impact of grinding surface concavity of on reaction force.

Checking for Impact of Concavity on Reaction force Analyse

Correlations: Reaction force, Grinding surface concavity

Pearson correlation of Reaction force and Grinding surface concavity = 0.073P-Value = 0.469


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Graphical DepictionGraphical Depiction Hypothesis ResultHypothesis Result

Inference : Since P-Value is 0.593(>0.05) so there is no significant co-relation between reaction force & Rivet height& as per Regression test also R-Sq is 0.3% (<62% ) , Hence there is no significant impact of Rivet height on reaction force.

Inference : Since P-Value is 0.593(>0.05) so there is no significant co-relation between reaction force & Rivet height& as per Regression test also R-Sq is 0.3% (<62% ) , Hence there is no significant impact of Rivet height on reaction force.

Checking for Impact of Rivet Height on Reaction force Analyse

Correlations: Reaction force, Revit height

Pearson correlation of Reaction force and Revit height = 0.054P-Value = 0.593


04/14/2333

Graphical Depiction

Graphical Depiction

Hypothesis Result Hypothesis Result

Inference : Since P-Value is 0.171(>0.05) so there is no significant co-relation between reaction force & Rivet dia & as per Regression test also R-Sq is 1.9% (<62% ) , Hence there is no significant impact of Rivet dia on reaction force.

Inference : Since P-Value is 0.171(>0.05) so there is no significant co-relation between reaction force & Rivet dia & as per Regression test also R-Sq is 1.9% (<62% ) , Hence there is no significant impact of Rivet dia on reaction force.

Checking for Impact of Rivet dia on Reaction force Analyse

Correlations: Reaction force, Revit dia

Pearson correlation of Reaction force and Revit dia = 0.138P-Value = 0.171


04/14/2334


Inference : Since P-Value is 0.234(>0.05) so there is no significant co-relation between reaction force & Hub run out & as per Regression test also R-Sq is 1.4% (<62% ) , Hence there is no significant impact of Hub run out on reaction force.

Inference : Since P-Value is 0.234(>0.05) so there is no significant co-relation between reaction force & Hub run out & as per Regression test also R-Sq is 1.4% (<62% ) , Hence there is no significant impact of Hub run out on reaction force.

Checking for Impact of Hub Run out on Reaction force Analyse

Correlations: Reaction force, Hub run out

Pearson correlation of Reaction force and Hub run out = 0.120P-Value = 0.234


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Checking for Impact of other Potential cause on Reaction force Analyse

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Hypothesis SummarySl. No. Factor P Value

Graphical Tool Used

Inference Next Steps

1 Washer thickness 0.000 Scatter plotSignificant impact as R-Sq=77.5 % (R-Sq >62%)

100 pcs hub sub assembly need to done with washer having thickness higher side.

2 Dimple dimension 0.053Scatter plot Non-significant

impact (R-Sq <62%)N.A

3 Armature flatness 0.095 Scatter plotNon-significant impact (R-Sq <62%) N.A

4 Hub assy flatness 0.256Scatter plot Non-significant

impact (R-Sq <62%) N.A

5 Grinding surface concavity 0.469Scatter plot Non-significant


6 Rivet height 0.593Scatter plot Non-significant


7 Rivet dia 0.171Scatter plot Non-significant


8 Hub run out 0.234Scatter plot Non-significant


Analyse

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MSA Results of Impacting Factors

Sl. No. FactorMSA

Method Used

ResultRCA for Problems

Next Steps

1 Washer thicknessANOVA Method

Pass (% R&R <9.01)

Analyse

04/14/2338

Improve

1. Screening of the Impacting Factors2. Action Plan for Improving the Factors3. Basic Analysis of Improved Y4. Pre–Post Analysis of Project Y5. Pre-Post Analysis of Factor6. Improve Summary – Take Aways

04/14/2339

Improve

1. Screening of the Impacting Factors

High Medium Low

In Control (1)Washer Thickness -(2) Machine Load Cell Variation(3) Flatness of Resting fixture

Out of Control

Con

trol

Impact

04/14/2340

Screening of the Impacting Factors Improve

Step1- Take 30 pcs of washer thickness having range size of 1.44~1.50 & assembled with hub & Armature & made a hub assy.Step 2- Check the reaction force for this hub assy. Step 3- Made graphical summary for observed reaction force to see the variation & central tendency of the data.Step 4- Also draw histogram to understand the frequency distribution of reaction force.Step5- Do normality plot of observed reaction force to understand the normal behaviour of the reaction force data.Step 6- Draw scatter plot to understand the nature of relationship between reaction force & washer thickness.

Trial -1,with washer thickness size 1.44~1.50.

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Conclusion : When we take 30 pcs of washer thickness with range 1.44~1.50.We get improper reaction force. At this range most of the times reaction force get at lower side & some time it goes below specification limit .

Conclusion : When we take 30 pcs of washer thickness with range 1.44~1.50.We get improper reaction force. At this range most of the times reaction force get at lower side & some time it goes below specification limit .

Trial-1 , Take 30 pcs of washer thickness with range of 1.44~1.50

04/14/2343

Conclusion : 1. Normality test shows that the observed reaction force is non-normal since the P-value is less than 0.05 (P-value<0.05).2. Scatter plot Reaction force & washer thickness shows the positive relationship.

Conclusion : 1. Normality test shows that the observed reaction force is non-normal since the P-value is less than 0.05 (P-value<0.05).2. Scatter plot Reaction force & washer thickness shows the positive relationship.


04/14/2344

Trial conclusion- When we take the washer range 1.44 to1.50 mm ,we get improper reaction force i.e some time reaction force is below specification limit.However, by increasing the washer thickness, reaction force is also increasing.


04/14/2345


Trial -2,with washer thickness size 1.51~1.56 mm

Step1- Take 30 pcs of washer thickness having range size of 1.51~1.56 & assembled with hub & Armature & made a hub assy.Step 2- Check the reaction force for this hub assy. Step 3- Made graphical summary for observed reaction force to see the variation & central tendency of the data.Step 4- Also draw histogram to understand the frequency distribution of reaction force.Step5- Do normality plot of observed reaction force to understand the normal behaviour of the reaction force.Step 6- Draw scatter plot to understand the nature of relationship between reaction force & washer thickness.

04/14/2346


04/14/2347


Conclusion : When we take 30 pcs of washer thickness with range 1.51~1.56,We get reaction force at lower side of specification , the current date is non-centric, Conclusion : When we take 30 pcs of washer thickness with range 1.51~1.56,We get reaction force at lower side of specification , the current date is non-centric,

04/14/2348


Conclusion : The normality plot shows that current data set is non-normal since P-value is less than 0.05, 2. The scatter plot shows that there is a positive relation ship between reaction force & washer thickness.

Conclusion : The normality plot shows that current data set is non-normal since P-value is less than 0.05, 2. The scatter plot shows that there is a positive relation ship between reaction force & washer thickness.

04/14/2349


Trial conclusion- When we take the washer range 1.51 to1.56 mm ,we get reaction force lower side of specification.However, by increasing the washer thickness, reaction force is also increasing.

04/14/2350


Trial -3,with washer thickness size 1.56~1.63 mm.


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ImproveScreening of the Impacting Factors

04/14/2352


Conclusion : When we take 30 pcs of washer thickness with range size of 1.56~1.63 mm , We get that reaction force observed is below nominal value & process is left hand skewness.Conclusion : When we take 30 pcs of washer thickness with range size of 1.56~1.63 mm , We get that reaction force observed is below nominal value & process is left hand skewness.

04/14/2353


Conclusion : 1.The normality plot shows that current data set is normal since P-value is greater than that 0.05, 2.The scatter plot shows that there is a positive relation ship between reaction force & washer thickness.

Conclusion : 1.The normality plot shows that current data set is normal since P-value is greater than that 0.05, 2.The scatter plot shows that there is a positive relation ship between reaction force & washer thickness.

04/14/2354


Trial conclusion- When we take the washer range 1.56 to1.63 mm ,we get reaction force lower side of nominal value i.e less than 110 Newton.However, by increasing the washer thickness, reaction force is also increasing.

04/14/2355


Trial -4,with washer thickness size 1.64~1.70.

Step1- Take 30 pcs of washer thickness having range size of 1.64~1.70 mm & assembled with hub & Armature & made a hub assy.Step 2- Check the reaction force for this hub assy. Step 3- Made graphical summary for observed reaction force to see the variation & central tendency of the data.Step 4- Also draw histogram to understand the frequency distribution of reaction force.Step5- Do normality plot of observed reaction force to understand the normal behaviour of the reaction force.Step 6- Draw scatter plot to understand the nature of relationship between reaction force & washer thickness.

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Conclusion : When we take 30 pcs of washer thickness with range size of 1.64~1.70 mm , We get that reaction force is falling around mean & also variation in data point is less.Conclusion : When we take 30 pcs of washer thickness with range size of 1.64~1.70 mm , We get that reaction force is falling around mean & also variation in data point is less.

04/14/2358


Conclusion : 1.The normality plot shows that current data set is normal since P-value is greater than that 0.05 ( P-value>0.126)2.The scatter plot shows that there is a positive relation ship between reaction force & washer thickness.


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Trial conclusion- When we take the washer range 1.64 to1.70mm ,we get reaction force is normally distributed around mean.However, by increasing the washer thickness, reaction force is also increasing.

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Trial -5,with washer thickness size 1.71~1.76 mm

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Conclusion : When we take 30 pcs of washer thickness with range size of 1.70~1.76 mm , We get that reaction force are normally distributed as P-value is greater than 0.05.Conclusion : When we take 30 pcs of washer thickness with range size of 1.70~1.76 mm , We get that reaction force are normally distributed as P-value is greater than 0.05.

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04/14/2364


Trial conclusion- When we take the washer range size of 1.71to1.76mm , we get reaction force observed is above nominal value but within specification limit.However, by increasing the washer thickness, reaction force is also increasing.

04/14/2365


If we take washer thickness more than 1.76 mm ,we face following problems-

1.Insufficient Rivet height – If we increase the washer thickness above 1.76 mm, then we have to also increase the rivet height for proper hub sub assy.

2. Spring plate dimple dimension need to change- If we increase the washer more than 1.76 , then we have to also increase the spring plate dimple dimension for getting proper reaction force.

Trial-6 , If we take Washer thickness greater than>1.76 mm

04/14/2366


Trial-6 , If we take Washer thickness greater than >1.76 mm

Trial conclusion- Since for washer thickness more than 1.76mm,we have to change rivet height & spring plate dimple dimension so we could not take this opportunity for trial to check reaction force. Because it involve high cost .

04/14/2367


Trial conclusion- By different trials we get the following results-

Trial Washer Thickness Obtained Reaction force (N) Required Rxn Force (N)Spec. Trial-1 1.44~1.50 mm 88~95 90-130 Trial-2 1.51~1.55 mm 90~98 90-130 Trial-3 1.56~1.63 mm 95~105 90-130Trial-4 1.64~1.70 mm 104.30~112.50 90-130Trial -5 1.70~1.76 mm 110~120.50 90-130Trial-6 >1.76 mm Can not check

Result- By above observations we have decided to revised washer thickness from 1.44-1.76 mm to 1.56~1.76 mm.

04/14/2368

Child part used in Hub sub assy. Improve

Hub Spring plate Rivet-1

Rivet-2 Hub Washer

Armature Hub sub assy.

04/14/2369

Impact of changing washer thickness Improve

Before After

Comments- Washer having thickness 1.60±0.16 mm.

Comments- Modified washer thickness with specification 1.66±0.1 mm.

Benefit- - Clearance between spring plate, hub & armature will ensured . - Modified washer thickness helped in reduction of reaction force NG Problem.

04/14/2370

Impact of changing washer thickness specification to other part specification Improve

Hub

Comments- Hub dimension no need to change.

Comments- Armature dimension no need to change.

Armature

04/14/2371

Impact of changing washer thickness specification to other part specification Improve

Spring plate

Comments- Spring plate dimension no need to change

Revit-1

Comments- Rivet-1, dimension no need to change .

Revit-2

Comments- Rivet-2, dimension no need to change .

04/14/2372

Action Plan for Improving the Factors

# Pain Area Root Cause Improvement IdeaImplement

ation Owner

Implementation

Status

1

Washer thickness having lower side specification cause improper reaction force.

Less washer thickness cause more clearance between spring plate, hub & armature create improper reaction force.

Washer thickness required specification range revised & new washer thickness range defined with less variation ,Current specification was1.44~1.76 mm which has been revised to new specification 1.56 ~1.76 mm, to get proper reaction force,

•Mr. Amit Sharma/Dipak pandey

Done

Improve

04/14/2373

Basic Analysis of Improved YRandomness Study Randomness Study

Spread Study Spread Study

Improve

Improved Reaction force shows that process is stable since data are randomly distributed around mean.

P-Value for clustering, mixtures, trends , oscillation are greater than 0.05.

P-Value for-

Clustering> 0.286

Mixtures>.714

Trends>0.197

Oscillation>0.803

04/14/2374

Basic Analysis of Improved YGraphical summary Graphical summary

Improve

Graphical summary for improved Reaction force shows that process is normally distributed around mean since P-Value >0.05 .

P-value for improved process is 0.062.

04/14/2375

Basic Analysis of Improved Y Improve

Histogram for improved Reaction force shows that date points are normally distributed around mean ,

Process is centric & process variation is also less.

Anderson Darling test for improved reaction force shows that data points are falling on straight line & data is normal since P-value > 0.05

P-value for improved reaction force P=0.062

04/14/2376


Improved process is capable since current process potential capability & actual capability are 3.01 & 2.30 respectively & which is acceptable as per AIAG guideline.

Current process potential performance & actual performance are 2.61 & 1.99 respectively Which is also acceptable as per AIAG guideline.

Current process is Stable & also in statistical control.

04/14/2377


Current process is acceptable as long term process capability (ZLT) is 5.97 & short term process capability (ZST) is 7.47.

Current process is stable & also is in stastical control.

PPM has been reduced till 937.5 i.e within given target.

04/14/2378


Before Improved project After Improved project

Six sigma project has been started to eliminate the same.

04/14/2379

Pre-Post Analysis of Project Y Reaction forceGraphical Description Before: Improvement Graphical Description Before: Improvement

Improve

Graphical Description After ImprovementGraphical Description After Improvement

The pre & post graphical distribution shows that pre-project the mean was 105.66 & post project this is 108.39, pre project the std. Dev was 13.05 & post project it is 6.06,also the P-value for pre project of improving reaction force was<0.05 & post project P-value is >0.05 i.e. 0.062,

04/14/2380

Pre-Post Analysis of Factor washer thicknessWasher Thickness Before improvementWasher Thickness Before improvement Washer Thickness After improvement Washer Thickness After improvement

Improve

The pre & post graphical distribution of washer thickness shows that before project the washer thickness variation is more & std. deviation is 0.0865 & the mean of the given data set is 1.589, while after improvement project the washer thickness variation is less & the std.dev is .0591 & the mean of the given date set is 1.668.

04/14/2381

Improve Summary – Take Aways Improve

Since low washer thickness cause improper reaction force so to get the correct washer thickness range, six trials for different washer thickness range done & used different statistical tool to see the relationship of getting reaction force with washer thickness. The result of all six trials are following- Trial Washer thickness Observed RXn force Specification limitTrial-1 1.44~1.50 mm 88~95 90-130 Trial-2 1.51~1.55 mm 90~98 90-130 Trial-3 1.56~1.63 mm 95~105 90-130Trial-4 1.64~1.70 mm 104.30~112.50 90-130Trial -5 1.70~1.76 mm 110~120.50 90-130Trial-6 >1.76 mm Not feasibleSince for washer thickness range 1.44~1.50 & 1.51~1.55 whatever the reaction force get that is either lower side or out side of desired specification.While by using washer thickness range 1.56~1.76 mm get better reaction force required for proper clutching.Trial for washer thickness range >1.76 mm can not do because for this washer thickness range ,rivet height & dimple dimension have to change so this is not feasible. So finally washer thickness range revised & decided a new washer thickness range of 1.56~1.76 mm, Made 100 pcs with modified washer thickness & checked reaction force ,Then draw the run chart found that data is stable, by graphical summary observed that data is normal & also calculate the capability of the process & is found that process is mature , stable & predictable.

04/14/2382

1. Control Plan & FMEA on Control Plan2. Time Series Study of Y – Pre & Post3. Control Charts & Inference for Y – Pre & Post4. Basic Analysis of Improved Y5. Establish Process Capability6. Control Charts & Inference (for X1)7. Control Charts & Inference (for X2)8. Cost Benefit Analysis and Sign Off

Control

04/14/2383

Control Plan & FMEA on Action Plan

What’s Controlled

Goal/Spec Limits

Control MethodWho/What Measures

Where Recorded

Decision Rule /

Corrective Action

SOP

1. Washer Thickness

1.66±0.1mm

5 Pcs check per lot in SQIG & Control chart

implemented to monitor the same.

SQIG Team/Washer thickness

Inspection check sheet

Washer thickness

must be within speciation.

Work instruction updated &

displayed at station for modified washer

thickness.

2. Reaction force

110±20 N

5 Pcs checked per shift & control chart implemented for monitoring the washer

thickness.

Line Engineer/Reaction

force

Product audit check sheet

Reaction force must be within specification.

Work instruction updated &

displayed at station

Control

04/14/2384

FMEA Review updating as per change washer thickness Improve

04/14/2385

Control Plan Review & updating Control

04/14/2386

Quality Plan Review Control

(1)Change in Washer thickness Dim. In Drawing & Inspection Test Plan.

04/14/2387

Control chart for Reaction Force Control

04/14/2388

Control Charts for Washer Thickness Control

04/14/2389

Basic Analysis of Improved Y Control

The pre & post graphical distribution shows that pre-project the mean was 105.66 & post project this is 108.39, pre project the std. Dev was 13.05 & post project it is 6.06,also the P-value for pre project for reaction force was<0.05 & post project P-value for same is >0.05 i.e 0.062.

04/14/2390

Z Bench (Long Term Sigma)

Short Term Sigma(Long Term Sigma +1.5)

5.97 7.47

Process Capability – Post Implementation

Establish Process Capability Control

Improved process is capable since current process capability is Cp=3.01 & Cpk =2.30 & current process performance is Pp=2.61 & Ppk =1.99

ZLT=5.97 & ZST=7.47

04/14/2391

ControlProject Summary

Define: It observed that hub assy Line rejection PPM reached up to 8526 PPM against target 1000 PPM due to improper clutching & clutch noise , caused by insufficient Reaction force between Hub & Rotor which leads to increase in customer complaints & hence customer dissatisfaction .Measure: Before Analysing the Problem we did- 1) validation of the measurement System by R & R Study and observed that the Measurement System is good enough for measuring the variation of the measurement System.2) Normality Test for the current Process data of Reaction Force which is found Non-Normal & very low Process Capability with one side skewness and draw run chart found that process is unstable.Analyze: During analysis we did brainstorming and validate all Potential Causes and found the Significant root Cause as improper reaction force is low washer thickness as reaction force is very much dependent on Washer thickness and check its effectiveness by performing co-relation & regression test.Improve: Since during analysis we found that assy line rejection PPM & customer complaint is due to improper clutching & clutch noise caused by insufficient Reaction force between Hub & Rotor and found that Improper clutching &clutch noise is due to less reaction force which we found is directly dependent on washer thickness.so we reduced the variation of the washer thickness to improve the reaction force.After implementation of new washer with revised thickness we checked the normality of Reaction force and found ok & Process capability of Washer thickness & Reaction force which is found more than 1.67 which confirms that the action taken has eliminated the root cause & hence reduce the assy line rejection PPM up to within target & customer complaint up to zero.Control: We Control the Action Plan taken by implementing the-1) Quality Plan for Washer thickness at Incoming Quality Stage.2) Control Chart for monitoring the Reaction Force & washer thickness and same has been updated in Control Plan & PFMEA.

04/14/2392

ControlProject Benefits

Compression Chart Pre & Post improvement

As per above comparison chart , we can see Line rejection PPM before improvement project was 8526 & customer complaint was 6 no's while after improvement project PPM is 937 ( which is within target) & customer complaint is 0.

04/14/2393

ControlCost Benefit Analysis

04/14/2394

Thanks Analysis

Education

Six Sigma Project for Improving Reaction Force