The document discusses using Six Sigma methodology to reduce in-process rejections at a manufacturing unit producing wheel cylinders. It analyzes the main causes of rejection, implements solutions, and measures the results. The key defects causing rejection were identified as main bore shift and M10 damage. Solutions like correcting hydraulic leaks, improving clamping, and modifying casting processes reduced monthly rejections from 205 to 15 and increased the sigma rating from 2.92 to 3.62, saving approximately $42,780 annually.
5. DMAIC FLOW CHART DEFINE MEASURE ANALYSE PROCESS OPPORTUNITY LIKELY BENIFITS CURRENT PERFORMANCE SOURCES OF VARIABILITY KEY VARIABLES RELATIONSHIPS IMPLEMENTED SOLUTION PREDECTED RESULTS IMPROVE CONTROL CONTROL VARIABLES PLAN FOR STABILITY
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8. Mounting hole drilling operation Drilling operation by Φ 3 drill Tapping operation by M6 tap Main bore drilling by Φ 15 solid carbide tool Followed by reaming by Φ 15.87 reamer Boot grooving operation by form tool Unloading the job and placing it to storage bin
9. MEASURE PHASE 3586 205 57161 November 4124 290 70319 October 5804 344 59265 September PPM Rejected jobs Total production Month
10. DEFECTWISE REJECTION 0 28 12 Poor finish 35 14 85 M 6 damaged 0 15 19 Acidic etching 0 10 25 Groove undersize 7 8 15 Groove steps 8 25 16 Bore or tool mark 15 25 09 Face damaged 50 70 76 M 10 damaged 90 85 107 Main bore shift NO. OF JOBS REJECTED DEFECT
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