1. IE405 QUALITY MANAGEMENT Recitation 7 -Process Capability Cp and Cpk values -Gage and Measurement System Capability Studies NOVEMBER 26TH 2002

2. Process Capability Ratios POTENTIAL CAPABILITY ACTUAL CAPABILITY

3. Rec7 Q1 PROCESS IS NOT CAPABLE POSSIBLE ALTERNATIVES -Change specification limits -Reduce variability

4. Rec7 Q1 Cpk for 700: –Cpu:0,818 ; Cpl:0,818 Process is producing product that does not conform to specifications. Cpk for 740 -Cpu: 0,4094 ; Cpl:1,22 Choose Cpu Producing products that do not conform to specifications

5. Rec7 Q1 Cpk for 780: –Cpu:0 ; Cpl:1,637Choose Cpu Average is equal to one of the specification limits Cpk for 740 -Cpu:- 0.409 ; Cpl:2,0473 Choose Cpu Average is outside specifications.

6. Rec7 Q2

8. Cp=2.05-1,99/6*0,0971 =0,1029 Process is not capable Cpk (Cpu:0,0186 ; Cpl:-0,187) choose Cpl Average is outside specification limits P(x 2.05) =0.017 1.7% defective

9. GAGE AND MEASUREMENT SYSTEM CAPABILITY STUDIES

10. Characteristics of the X and R charts in gage and measurement system capability studies DISCRIMINATINGX chart shows the DISCRIMINATING POWER of the instrument, ability of the gage to distinguish between units of product. R chart shows the MAGNITUDE of measurement error, or gage capability. R values represent the difference between measurements made on the same unit using the same instrument.

11. Components of Measurement Error Reproducibility : due to different operators using the gage (different time periods,different environments, or in general different conditions) Repeatibility: as reflecting the basic inherent precision of the gage itself

12. OPE R A T O R 1 XbarR OPE R A T O R 2 XbarR Part Number123 123 15454,6666671554 1 2444404454,3333331 35544,666667144440 44454,33333313443,6666671 5555505565,3333331 4,5333330,6 4,40,8

13. Rec7 Q3 REPEATABILITY REPRODUCIBILITY

14. Rec7 Q3 P/T OF 0.1 or LESS often implies adequate gage capability