sscasestudy.ppt
- 1. D M A I C Define Measure Analyze Improve Control D Define M Measure A Analyze I Improve C Control Implementing Six Sigma Quality at Better Body Manufacturing
- 2. 2 D M A I C Define Measure Analyze Improve Control Dimension DPM ASM_7Y 172475 ASM_8Y 85824 ASM_3Y 19786 ASM_9Y 3874 ASM_10Y 776 ASM_6Y 4 Overview ABC Incorporated (ABC) is not achieving Six Sigma quality levels for all critical Body-Side Sub-Assembly dimensions as requested by their customers. Ensure that all critical body-side subassembly dimensions are within Six Sigma quality levels of < 3.4 DPM. Cp 鰹2.0 and Cpk 鰹1.67. Change tonnage to > 935 to correct ASM_7Y and ASM_8Y Set clamp position to location 2 for ASM_9Y and ASM_10Y Re-machine A-pillar die to correct A_3Y and ASM_3Y Determined the correlation between body side and assembly dimensions. Evaluated the significance of Tonnage > 935 for ASM_7Y & ASM_8Y. Conducted a DOE for Clamp position for ASM_9Y & ASM_10Y. 0 50000 100000 150000 200000 ASM_7Y ASM_8Y ASM_3Y ASM_9Y ASM_10Y ASM_6Y DPM
- 3. 3 D M A I C Define Measure Analyze Improve Control Problem Statement & The Goal ABC Incorporateds customer wants ABC to apply Six Sigma problem solving methodology to insure that the body side subassembly is achieving Six Sigma quality levels of less than 3.4 defects per million for all critical body side subassembly dimensions. ABC needs an improvement strategy that minimizes the rework costs while achieving the desired quality objective. ABCs goal is to produce module subassemblies that meet the customer requirements and not necessarily to insure that every individual stamped component within the assembly meets it original print specifications sub-system optimizations vs. local optimization. + + A-Pillar Reinforcement B-Pillar Reinforcement Body Side Outer + + A-Pillar Reinforcement B-Pillar Reinforcement Body Side Outer D Define
- 4. 4 D M A I C Define Measure Analyze Improve Control Measure Phase Key Variables: Assembly process variables: Weld Pattern (density), Clamp Location, and Clamp Weld Pressure Stamping process variables (body side): Press Tonnage, Die Cushion Pressure, Material Thickness Body Assembly Dimensions ASM_1Y through ASM_10Y M Measure 4 776 172475 85824 19786 3874 0 50000 100000 150000 200000 ASM_7Y ASM_8Y ASM_3Y ASM_9Y ASM_10Y ASM_6Y DPM Assembly Dimensions with Highest Defects
- 5. 5 D M A I C Define Measure Analyze Improve Control Resolution alternatives (based upon past experience): 1. Make adjustments to assembly process settings 2. Reduce variation of components through better control of stamping process input variables 3. Rework stamping dies to shift component mean deviation that is off target and causing assembly defects Target Performance Level: All ten critical assembly dimensions at Six Sigma quality level of 3.4 DPM. Cp 鰹2.0 and Cpk 鰹1.67 Fish Bone and P-Diagrams: Understanding potential causes of defects. From this we pick the assembly and component dimensions that require further analysis Analyze Phase A Analyze
- 6. 6 D M A I C Define Measure Analyze Improve Control For our analysis we will do a DOE to check for levels that contribute to better quality product. Weld Pattern (density) Clamp Location Operator Machine Materials Methods Clamp Weld Pressure Press Tonnage Die Cushion Pressure Material Thickness Training Yield Strength Elastic Limit Environment Temperature Humidity Quality Component Variability Inspection Process Gage R&R Body Assembly Analyze Phase A Analyze Body Side Sub-Assembly Stamping Process Outputs Body Side Sub-Assemblies at Six Sigma quality levels Control Variables Clamp Location Press Tonnage Weld Density Die Pressure Clamp Pressure Error States Dimensional defects Noise Variables Environment Inherent Variation Inputs Material Thickness Yield Strength
- 7. 7 D M A I C Define Measure Analyze Improve Control Analysis of ASM_7Y and ASM_8Y 2 7 12 0.0 0.5 1.0 Subgroup Number ASM_7Y Number of runs about median: Expected number of runs: Longest run about median: Approx P-Value for Clustering: Approx P-Value for Mixtures: Number of runs up or down: Expected number of runs: Longest run up or down: Approx P-Value for Trends: Approx P-Value for Oscillation: 4.00000 7.00000 5.00000 0.03464 0.96536 6.00000 7.66667 3.00000 0.10778 0.89222 Run Chart for ASM_7Y 2 7 12 0.0 0.5 1.0 Subgroup Number ASM_8Y Number of runs about median: Expected number of runs: Longest run about median: Approx P-Value for Clustering: Approx P-Value for Mixtures: Number of runs up or down: Expected number of runs: Longest run up or down: Approx P-Value for Trends: Approx P-Value for Oscillation: 4.00000 7.00000 5.00000 0.03464 0.96536 8.00000 7.66667 2.00000 0.59781 0.40219 Run Chart for ASM_8Y Analyze Phase A Analyze Conclusion: BS_7Y and ASM_7Y are following a similar trend. A correlation chart to study this further shows high correlation. (Pearson correlation, R of 0.701). 0.0 0.5 1.0 0.0 0.5 1.0 ASM_8Y ASM_7Y XY Plot of ASM_8Y and ASM_7Y
- 8. 8 D M A I C Define Measure Analyze Improve Control Analyze Phase A Analyze -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 LSL USL Capability Analysis of B_7Y USL Target LSL Mean Sample N StDev(Within) StDev(Overall) Cp CPU CPL Cpk Cpm Pp PPU PPL Ppk PPM< LSL PPM> USL PPMTotal PPM< LSL PPM> USL PPMTotal PPM< LSL PPM> USL PPMTotal 0.70 * -0.70 0.11 36 0.0788122 0.0791215 2.96 2.50 3.43 2.50 * 2.95 2.49 3.41 2.49 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Process Data Potential (Within) Capability Overall Capability Observed Performance Exp. "Within" Performance Exp. "Overall" Performance Within Overall Capability of B_7Y -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 LSL USL Capability Analysis of BS_7Y USL Target LSL Mean Sample N StDev(Within) StDev(Overall) Cp CPU CPL Cpk Cpm Pp PPU PPL Ppk PPM< LSL PPM> USL PPMTotal PPM< LSL PPM> USL PPMTotal PPM< LSL PPM> USL PPMTotal 0.700000 * -0.700000 0.899444 36 0.149640 0.383691 1.56 -0.44 3.56 -0.44 * 0.61 -0.17 1.39 -0.17 0.00 666666.67 666666.67 0.00 908706.09 908706.09 15.33 698400.06 698415.39 Process Data Potential (Within) Capability Overall Capability Observed Performance Exp. "Within" Performance Exp. "Overall" Performance Within Overall 698416 DPM 0 DPM 0.5 1.0 1.5 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 ASM_7Y BS_7Y XY Plot of ASM_7Y and BS_7Y Conclusion: B_7Y has 0 ppm compared to ~700K DPM in BS_7Y. Furthermore, BS_7Y shows strong correlation on dimension ASM_7Y. (Pearson correlation, R of 0.786). Capability of BS_7Y
- 9. 9 D M A I C Define Measure Analyze Improve Control 905 915 925 935 945 0.5 1.0 1.5 Tonnage BS_7Y XY Plot of Tonnage vs. BS_7Y XY Plot of Tonnage vs. BS_7Y Conclusion: Tonnage values above 935 greatly improves BS_7Y and brings it closer to the mean. Lets see what impact this has on ASM dimensions 7Y, 8Y, 9Y, and 10Y by creating a subset of the data looking only at Tonnage > 935. Analyze Phase A Analyze
- 10. 10 D M A I C Define Measure Analyze Improve Control Analyze Phase A Analyze -1.0 -0.5 0.0 0.5 1.0 LSL USL Capability Analysis of ASM_7Y at Tonnage > 935 USL Target LSL Mean Sample N StDev (Within) StDev (Overall) Cp CPU CPL Cpk Cpm Pp PPU PPL Ppk PPM < LSL PPM > USL PPM Total PPM < LSL PPM > USL PPM Total PPM < LSL PPM > USL PPM Total 1.00 * -1.00 0.09 12 0.163174 0.147855 2.04 1.86 2.23 1.86 * 2.25 2.05 2.46 2.05 0.00 0.00 0.00 0.00 0.01 0.01 0.00 0.00 0.00 Process Data Potential (Within) Capability Overall Capability Observed Performance Exp. "Within" Performance Exp. "Overall" Performance Within Overall -1.0 -0.5 0.0 0.5 1.0 LSL USL Capability Analysis of ASM_8Y at Tonnage > 935 USL Target LSL Mean Sample N StDev (Within) StDev (Overall) Cp CPU CPL Cpk Cpm Pp PPU PPL Ppk PPM < LSL PPM > USL PPM Total PPM < LSL PPM > USL PPM Total PPM < LSL PPM > USL PPM Total 1.00000 * -1.00000 -0.12833 12 0.101825 0.089161 3.27 3.69 2.85 2.85 * 3.74 4.22 3.26 3.26 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Process Data Potential (Within) Capability Overall Capability Observed Performance Exp. "Within" Performance Exp. "Overall" Performance Within Overall -1.0 -0.5 0.0 0.5 1.0 LSL USL Capability Analysis of ASM_9Y at Tonnage > 935 USL Target LSL Mean Sample N StDev (Within) StDev (Overall) Cp CPU CPL Cpk Cpm Pp PPU PPL Ppk PPM < LSL PPM > USL PPM Total PPM < LSL PPM > USL PPM Total PPM < LSL PPM > USL PPM Total 1.00000 * -1.00000 0.52083 12 0.206010 0.177098 1.62 0.78 2.46 0.78 * 1.88 0.90 2.86 0.90 0.00 0.00 0.00 0.00 10010.77 10010.77 0.00 3408.51 3408.51 Process Data Potential (Within) Capability Overall Capability Observed Performance Exp. "Within" Performance Exp. "Overall" Performance Within Overall -1.0 -0.5 0.0 0.5 1.0 LSL USL Capability Analysis of ASM_10Y at Tonnage > 935 USL Target LSL Mean Sample N StDev (Within) StDev (Overall) Cp CPU CPL Cpk Cpm Pp PPU PPL Ppk PPM < LSL PPM > USL PPM Total PPM < LSL PPM > USL PPM Total PPM < LSL PPM > USL PPM Total 1.00 * -1.00 0.39 12 0.215541 0.187663 1.55 0.94 2.15 0.94 * 1.78 1.08 2.47 1.08 0.00 0.00 0.00 0.00 2326.72 2326.72 0.00 576.00 576.00 Process Data Potential (Within) Capability Overall Capability Observed Performance Exp. "Within" Performance Exp. "Overall" Performance Within Overall Conclusion: Setting Tonnage to greater than 935 resulted in ASM_7Y and ASM_8Y meeting the goal of <3.4 DPM. ASM_9Y and ASM_10Y require further analysis. Impact this has on ASM dimensions 7Y, 8Y, 9Y & 10Y on Tonnage
- 11. 11 D M A I C Define Measure Analyze Improve Control DOE for Response Variable ASM_9Y DOE factorial analysis shows Clamp Position is the only significant factor in determining ASM_9Y dimension DOE Response Optimization for ASM_9Y Set Clamp Position to Location 2 (level 1) Optimizer recommends setting Weld Density to 1.33 weld per inch (level 1), but this appears to be a robust parameter, which could be changed for the benefit of process without reducing quality if processing time or cost shows a benefit. Optimizer recommends setting Clamp Pressure to 2100 psi (level 1), but this appears to be a robust parameter, which could be changed for the benefit of process without reducing quality if processing time or cost shows a benefit. Run additional tests at recommended settings to confirm results Weld Density and Clamp Pressure are robust parameters and can be set to optimize the process capability to maximum level and lowest cost. Analyze Phase A Analyze Input Variable Proposed ASM_9Y Setting Proposed ASM_10Y Setting Clamp Location Location 2 Location 2 Weld Density (welds per X inches) 1.33 1.33 Clamp Pressure 2100 psi 2100 psi
- 12. 12 D M A I C Define Measure Analyze Improve Control Analyze Phase A Analyze DOE for Response Variable ASM_10Y DOE factorial analysis shows Clamp Position is also the only significant factor in determining ASM_10Y dimension DOE Response Optimization for ASM_10Y Setting clamp to location 2 also improves ASM_10Y Recommend same settings used to improve ASM_9Y to improve process capability which also allows for no changes to machine setup and helps reduce possible process concerns Run additional tests at recommended settings to confirm results Weld Density and Clamp Pressure are robust parameters and can be set to optimize the process capability to maximum level and lowest cost.
- 13. 13 D M A I C Define Measure Analyze Improve Control DOE for Response Variable ASM_3Y DOE factorial analysis shows that no factors are significant Response Optimization shows no solution for response optimizer Observe Process Capability of A_3Y and BS_3Y ASM_3Y and A_3Y have a similar mean shift in the -Y direction Correlation of Output Variables No dimensional correlations appear to exist between ASM_3Y and A_3Y or BS_3Y Stepwise Regression Analysis of BS_3Y Tonnage and Die Pressure appear to be significant in determining dimension BS_3Y Tonnage values < 920 may improve BS_3Y Die Pressure appears to have no clear correlation to BS_3Y Analyze Phase A Analyze
- 14. 14 D M A I C Define Measure Analyze Improve Control Process Capability of BS_ 3Y and ASM_3Y at Tonnage < 920 Created subset of body data looking only at dimensions with Tonnage < 935 Tonnage < 920 appears to improve the mean of BS_3Y slightly, but has no impact on improving the mean of ASM_3Y. -1.0 -0.5 0.0 0.5 1.0 LSL USL Capability Analysis of ASM_3Y USL Target LSL Mean Sample N StDev (Within) StDev (Overall) Cp CPU CPL Cpk Cpm Pp PPU PPL Ppk PPM < LSL PPM > USL PPM Total PPM < LSL PPM > USL PPM Total PPM < LSL PPM > USL PPM Total 1 * -1 0 36 0.0851436 0.0971725 3.91 3.91 3.91 3.91 * 3.43 3.43 3.43 3.43 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Process Data Potential (Within) Capability Overall Capability Observed Performance Exp. "Within" Performance Exp. "Overall" Performance Within Overall Die remachined to move mean +0.80 Capability of A_3Y and ASM_3Y with +0.80 mm mean offset Manipulate data for A_3Y and ASM_3Y by +0.80 mm to simulate re-machining Process capability shows 0 defects for A_3Y and ASM_3Y with this mean offset Analyze Phase A Analyze
- 15. 15 D M A I C Define Measure Analyze Improve Control Analyze Phase A Analyze Conclusions From the analysis of ASM_7Y and ASM_8Y we can conclude that: Setting tonnage > 935 results in ASM_7Y and ASM_8Y meeting the goal Analyzing ASM_9Y and ASM_10Y helps determine that: Setting clamp position to location 2, weld density to 1 weld every 1.33 and clamp pressure to 2000 psi helps with dimensions ASM_9Y and ASM_10Y Analyzing ASM_3Y helps us conclude that: Re-machine A-Pillar die to move A_3Y to nominal which could cause BS_3Y to shift towards nominal effectively shifting ASM_3Y to nominal
- 16. 16 D M A I C Define Measure Analyze Improve Control With the recommended changes the process performance will improve significantly Dimension Mean StDev Overall DPM_Obsv DPM_Within DPM_Exp Pp Ppk Cp Cpk ASM_1Y -0.035 0.165 0 0 0 2.01 1.94 2.47 2.39 ASM_2Y 0.259 0.152 0 0 1 2.20 1.63 2.31 1.71 ASM_3Y 0.000 0.097 0 0 0 ASM_4Y 0.009 0.115 0 0 0 2.90 2.87 3.53 3.50 ASM_5Y -0.330 0.145 0 0 2 2.30 1.54 3.72 2.50 ASM_6Y -0.284 0.160 0 1 4 2.08 1.49 2.24 1.60 ASM_7Y 0.090 0.148 0 0 0 2.25 2.05 2.04 1.86 ASM_8Y -0.128 0.089 0 0 0 3.74 3.26 3.27 2.85 ASM_9Y 0.521 0.180 0 0 0 ASM_10Y 0.395 0.191 0 0 0 A Analyze Analyze Phase
- 17. 17 D M A I C Define Measure Analyze Improve Control Recommendations for improving the process: Set Tonnage to above 935 to improve ASM_7Y & ASM_8Y Set Clamp to Location 2 to improve ASM_9Y & ASM_10Y Re-machine the A-Pillar die to move the mean of A_3Y to nominal which in turn will move ASM_3Y to nominal Implement the above recommendations and run additional samples to verify results. I Improve Improve Phase
- 18. 18 D M A I C Define Measure Analyze Improve Control Control Phase C Control Recommended controls : Implement a gauge on the body side component press to monitor tonnage Implement an alarm and shut-off feature on the body side press if tonnage falls below 935 tons Implement poke-yoke clamping fixture that ensures clamp is always in Position 2 Establish an affordable control plan for ongoing monitoring of the 10 critical assembly dimensions.
- 19. 19 D M A I C Define Measure Analyze Improve Control Summary ABC Incorporated is not achieving Six Sigma quality levels for all critical Body- Side Sub-Assembly dimensions as requested by their customers. BBM needs to apply Six Sigma problem solving methodology to establish an improvement strategy that minimizes rework costs, yet achieves the desired quality objective. Implement a gauge on the body side component press to monitor tonnage Implement an alarm & shut-off feature on body side press if tonnage falls below 935 Implement poke-yoke clamping fixture that ensures clamp is always in Position 2 Establish control plan for ongoing monitoring of the 10 critical assembly dimensions. Set Tonnage to above 935 to improve ASM_7Y & ASM_8Y Set Clamp to Location 2 to improve ASM_9Y & ASM_10Y Re-machine the A-Pillar die to move the mean of A_3Y to nominal Bring the key process output variables within Six Sigma quality level of < 3.4 DPM. Cp 鰹2.0 and Cpk 鰹1.67