質(zhì)量管理七大手法(英文版)-文庫吧在線文庫
【正文】 (UCL) is mean value +3σ and Lower Control Limit is mean value 3σ. +3σ +2σ +1σ 1σ 2σ 3σ CL UCL LCL Relationship between σ and defective percentage 1 σ 2 σ 3 σ 4 σ 5 σ 6 σ % % % 6210PPM 233PPM M *Considering influences from various factors. * represents 1350ppm defectives. Comparing 6σ and 3σ, defective percentage reduced 20,000 times! Motorola request his supplier provide products with 6σ quality。 ? 3. Method: No WI or WI content not related to actual work. QC 7 Tools Scatter Diagram ? What is scatter diagram? ? A diagram to find out whether there is any relationship between two variables by plotting the data in XY axle coordinates. Types of scatter diagram ? Generally there are 4 types of scatter diagram: ? Positive correlation (X↑ , Y↑ )。 operator, machine, material, working (process). Pareto diagram procedure ? Take the defects found in a figure production for example, total 15854 products, including 216 defectives. ? 1. Collect data ? 2. Sort order (descending), and count accumulative percentage. No Category Defect Defect % Accumulative Defect % 1 Dirt Mark 75 % % 2 Paint migration 47 % % 3 Scratch mark 39 % % 4 Excessive flash 28 13% % 5 Insufficient glue 17 % % 6 White mark 7 % % 7 Other 3 % % Total ∑ 216 % % Pareto diagram procedure ? 3. Draw X axis and Y axis and marking scale. ? 4. Draw histogram. ? 5. Draw accumulative curve. ? 6. Analyze Pareto diagram and take corrective action. (Very important). P a r e t o d i a g r a m7547392817733 4 . 7 0 %5 6 . 5 0 %7 4 . 5 0 %8 7 . 5 0 %9 5 . 4 0 %9 8 . 6 0 %100%01020304050607080D i r t M a r k P a i n tM i g r a t i o nS c r a t c hM a r kE x c e s s i v eFl a s hI n s u f f i c i e n tg l u eW h i t e M a r k O t h e rD e f e c t de s c r i pt i onDefective amount0%20%40%60%80%100%defective percentage QC 7 tools Causeandeffect diagram ? What is Causeandeffect diagram? ? It is a tool to analyze the quality characteristics (effect) and the potential factor to effect the characteristics (cause). Key points ? 1. Personnel from different Dept。 6mm: 1 2 3 4 5 6 7 8 9 10
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