1. L. G OCH – F EBRUARY 2011 SPC & MSA Using Minitab

2. A GENDA Continuous & Attribute Data IMR Charts Xbar & R Charts Xbar & S Charts MSAs Using Xbar & S Charts for MSAs Non-Destructive Variable MSAs (NOTE: Minitab will also Analyze Destructive Variable MSAs & Attribute MSAs)

3. DATA PLOTTED OVER TIME MONITORED CHARACTERISTIC UCL Center Line LCL UCL = Upper Control Limit / LCL = Lower Control Limit Plotted Data T HE B ASIC C ONTROL C HART K EY C OMPONENTS Control Limits are NOT Spec Limits

4. C OMMON C AUSES VS S PECIAL C AUSES

5. Individual-X & Moving Range Chart

6. C ONTROL C HARTS I NDIVIDUAL /M OVING R ANGE Use: When only have 1 measurement per time period When want to chart Counts. When want to chart Percentages (%’s). Do NOT use P-Charts if the values are 100 since it violates basic P-Chart assumptions. Need a minimum of 10 data points Variation Moving Range chart Short Term: Measures relatively rapid changes over time (Moving Range chart) Individuals chart Long Term: Measures relatively gradual changes over time(Individuals chart) Charts are Based on a Subgroup Size of 1

7. I / MR C HART : S TAT > C ONTROL C HARTS > I-MR Exh_QC.mtw Open worksheet Exh_QC.mtw I-MR Chart analyzes individual data over time.

8. I / MR C HART : S TAT > C ONTROL C HARTS > R UN C HART Rule #1

9. Is there a shift at Observation # 25? M INITAB E XERCISE I NDIVIDUALS / M OVING R ANGE O UTPUT

10. Group Column Added

11. M INITAB E XERCISE I NDIVIDUALS / M OVING R ANGE O UTPUT Press e

12. M INITAB E XERCISE I NDIVIDUALS / M OVING R ANGE O UTPUT

13. Xbar & R Chart

14. C ONTROL C HARTS X B AR / R C HART Advantages Sensitive to changes in dataLimitation Unlike the Individual Chart, the Xbar Chart control limits do not represent the overall data range. They represent the range of the subgroup averages.

15. C ONTROL C HARTS X- BAR / R C ONTROL C HARTS GATHERING DATA GATHERING DATA Define rational basis for subgrouping Select sample size for the subgroups Select sampling frequency Need a minimum of 10 subgroupsVARIATION Short Term: Measures the variation within the Subgroups based on the subgroup range (Range chart) Long Term: Measures the variation between the Subgroups based on the subgroup average (X Bar chart)

16. X BAR -R C HARTS : S TAT > C ONTROL C HARTS > V ARIABLES C HARTS FOR S UBGROUPS > X BAR -R Camshaft.mtw Open worksheet Camshaft.mtw

17. M INITAB E XERCISE - XB AR / R C HARTS O UTPUT What do the Charts tell us? We need to look at the individual suppliers.

18. M INITAB E XERCISE - XB AR / R C HARTS Stack Data: o Stack Data: Stack the 2 Suppliers so the data can be looked at together on the same chart

19. M INITAB E XERCISE - XB AR / R C HARTS

20. Xbar & S Chart

21. C ONTROL C HARTS X B AR / S C HART Advantages Very sensitive to changes in data. Also, the center line of the S-Chart provides a good estimate for the data’s standard deviation.Limitation The Xbar Chart control limits do not represent the overall data range. They represent the range of the subgroup averages.

22. C ONTROL C HARTS X- BAR / S C ONTROL C HARTS GATHERING DATA GATHERING DATA Define rational basis for subgrouping An S-Chart is typically used when the subgroup’s sample size is > 9 Select sampling frequency Need a minimum of 10 subgroupsVARIATION Short Term: Measures the variation within the Subgroups based on the subgroup stddev (S chart) Long Term: Measures the variation between the Subgroups based on the subgroup average (X Bar chart)

23. X BAR -S C HARTS : S TAT > C ONTROL C HARTS > V ARIABLES C HARTS FOR S UBGROUPS > X BAR -S Bloodsugar.mtw Open worksheet Bloodsugar.mtw

24. M INITAB E XERCISE - XB AR / S C HARTS O UTPUT What do the Charts tell us? We need to look at the individual people.

25. M INITAB E XERCISE - XB AR / S C HARTS Sort Data: o Sort Data: Sort the data by SubjectID & Reading

26. M INITAB E XERCISE – I-MR C HARTS

27. Xbar & S Charts used for MSA’s

28. MSA: X B AR / S C HART Advantages Pictorial look at MSA results Measurement error can easily be calculated % R&R and %P/T can easily be calculated Daily Calibration Data can be usedLimitation Will NOT detect measurement that varies by nominal value (e.g. large parts having more or less measurement error than small parts)

29. MSA: X- BAR / S C HART GATHERING DATA GATHERING DATA Need Multiple measurements per time period Can use 1 or more Parts Need a minimum of 10 subgroupsVARIATION S Chart: Displays the Measurement Error. A good measurement system will be in-control Xbar Chart: Displays any Drift over time in the average measurements. A good measurement system will be in- control for each individual Part.

30. MSA: X- BAR / S C HART Multiple Measurements per Day on most Days. 1 Calibration Part per Facility 3 Facilities Sorted by Facility Date & Time Daily Calibration Data.mtw Open worksheet Daily Calibration Data.mtw

31. X BAR -S C HARTS : S TAT > C ONTROL C HARTS > V ARIABLES C HARTS FOR S UBGROUPS > X BAR -S Daily Calibration Data.mtw Open worksheet Daily Calibration Data.mtw

32. MSA: X- BAR / S C HART OUTPUT Need to add the Measurement Error.

33. MSA: X- BAR / S C HART R ESULTS Comments Comments Spec is +/- 50. %P/T target is < 30% None of Facilities meet the measurement error target Daily Calibration Check procedures need investigated since producing dramatically different results Facilitly~SbarMultiplier ~ Meas Error%P/T DHM31.02.575+/- 8080/50 = 160% DSM27.52.575+/- 7171/50 = 142% GSO 8.02.575+/- 2121/50 = 42%

34. Variables MSA (Non-Destructive Testing)

35. V ARIABLES MSA: S TAT > Q UALITY T OOLS > G AGE S TUDY > G AGE R&R S TUDY (C ROSSED ) Minimum Requirements Minimum Requirements Minimum 10 parts: ~3 at low end of spec, ~4 parts in middle of Spec, ~3 parts at high end of spec (NOTE: some parts should be out of spec) 3 Operators (NOTE: if only 1 operator measures parts, 1 operator may be used for MSA) 3 Repeated Measurements

36. V ARIABLES MSA: S TAT > Q UALITY T OOLS > G AGE S TUDY > G AGE R&R S TUDY (C ROSSED )

38. V ARIABLES MSA: G RAPH R ESULTS

39. V ARIABLES MSA: S ESSION W INDOW R ESULTS Measurement Error: +/- 0.78 (i.e. 1.55721/2 = 0.78) Both the Part & the Operator significantly effect the part measurements.

40. SPC/MSA - S UMMARY The reliability of Control Charts are dependent on the selection of Rational Subgroups. Pick the wrong subgroup and the results can be very misleading. The reliability of MSAs are dependent on the selection of the actual Parts. Pick Parts with too much or too little variation between them and the results can be very misleading.