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1. 1 Six Sigma Green Belt Project
1556-00 FFABS
Reduction in Measurement Variation During In-Process Dimensional Inspection
Green Belt Candidate, Tempe
04/20/07
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3. 3 Define
A Fishbone Diagram was used to help determine where the major influence was coming from.
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This shows where the potential for variation exists.
6. 6 The Cause and Effect Matrix shows the impact that the key inputs have on our Customer Requirements.
7. 7 F.M.E.A ScaleThe following scale is used to rank the importance of the potential areas or conditions that would prevent us from completing the Dimensional Inspection accurately.
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9. 9 Measurement System AnalysisZeiss Vista CMM
10. 10 Measurement System AnalysisZeiss Vista CMM As seen on the previous slide, all of the variation is coming from the parts with a Variance of < 1% coming from the CMM.
11. 11 AnalyzeThere are 9 Critical Dimensions specified by the Customer that are checked 2 times per shift and recorded. The following slides represent the historical capability of each dimension as measured across all 3 shifts.
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14. 14 An ANOVA was performed on each of the 9 Critical Dimensions to see if there was a significant difference in the mean between shifts. It was noted that 4 of the 9 criticals exhibited an Alpha of < .05 indicating that the means were significantly different.
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16. 16 Main Effects Plots were generated to show the Shift to Shift variance of the means.
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19. 19 Improve The ‘Improve’ phase of this project will focus on training. The Zeiss CMM Operating Instructions and Troubleshooting Tips Manual has been updated to reduce the amount of influence the Quality Inspector has in choosing the probing points for the Base/Start Alignment features.
Original Setup Instructions:
20. 20 Improved/Updated Setup Instructions:
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22. 22 A Training Outline has been created for evaluation during the Improvement phase to ensure consistency between all training sessions.
23. 23 A Training Evaluation Survey is also being utilized to improve training content or methods as necessary.
24. 24 The following slides represent the improved capability of each dimension across all 3 shifts.
25. 25 The chart on the left shows the Capability of the 2.084 +/- .008 Dimension as specified on the print. The chart on the right shows the Capability with the adjusted tolerances of 2.084 +.011/-.000 as allowed by the Customer.
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27. 27 The following data shows the reduction in the Standard Deviation of the critical dimensions as measured across all 3 shifts.
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29. 29 Shift to Shift Variation
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32. 32 ControlControl of the In-Process Dimensions will be monitored using QC Calc. Data is transferred in real time as the dimensions are being measured. Any out of control dimensions can be dealt with according to procedure. Statistical graphs shown below are consistent with the approved PPAP from the Customer.
33. 33 ConclusionThe Standard Deviation was reduced during this project using more detailed instructions and improving training. The CMM used to measure these parts has an MSA of <1%. By controlling Base/Start Alignment point selection, the influence the QA Inspector has on the overall outcome of the readings can be minimized. It can be determined at this time that the remaining variance that is being seen can be attributed to normal process variation during production.