六西格玛绿带培养训练教材(英文版).ppt

GRR Long Method Example Using GRR matrix of : 10 Parts, 3 Operators, 2 trials S2 measurement = S2 repeatability + S2 reproducibility = (0.047)2 + (0.011)2 = 0.02209 + 0.000121 = 0.00233 S measurement = 0.048 S reproducibility = R(Xbar) / d2 = (4.04 - 4.03) / 1.69 = 0.011 Average Rbar = (0.06 + 0.05 + 0.05) / 3 = 0.05333 S repeatability = Average Rbar / d2 = 0.05333 / 1.13 = 0.047 GRR Long Method (con’t) Given specification = 3.8 +/- 0.5 GRR (Tolerance) = (6 x 0.048) / (1) = 0.288 GRR (Total) = (0.048) / 0.241 = 0.200 Graphical Interpretation of GRR LCL = Avg m – (Rbar x A2) UCL = Avg m + (Rbar x A2) LCL UCL Very good repeatability for operator 3 Poor reproducibility because of operator 1, repeatability for operator 1 is also bad. Graphical Interpretation of GRR (con’t) Assuming operator is not a trained inspector, the expected result will be: Conducting GRR Using Long Method Determine GRR matrix. Number the parts, but do not let the operators / inspectors know that you are conducting a gauge study. Calibrate the gauge. Let the operators / inspectors measure the parts in random order. When repeating trials, re-shuffle the parts before letting the operators / inspectors conduct the measurements. Use operator / inspectors from different shift if possible Tally the result 和compute GRR Interpret the result graphically if necessary If Repeatability is the problem Replace, repair or adjust the equipment. Revise the standard operating procedure. If Reproducibility is the problem Examine the difference between operators 和determine if it is due to insufficient 培训, or inspector not following the SOP. If P/TOL 0.30 Check if the specification limits is reasonable or attainable If P/TOT 0.30 Check the items that we