1. Engineering Management Six Sigma Quality Engineering Week 5 Chapters 5 (Measure Phase) Variable Gauge R&R “Data is only as good as the system that measures it. If you can’t measure it, you can’t manage it.”

2. “I often say that when you measure what you are speaking about and express it in numbers, you know something about it.” LORD KELVIN, 1891 He clearly stressed that little progress is possible in any field of investigation without the ability to measure. The progress of measurement is, in fact, the progress of science. The Science of Measurement

3. Objectives Measurement Systems Analysis Key Terminology Variable Gauge R&R A tool for estimating measurement system error How to conduct a gauge R&R Minitab Output Gauge R & R Study Exercise

4. Definitions Variable Data Continuous measurements such as length, voltage, viscosity Repeatability Variation in measurements obtained with one gage when used several times by one appraiser. Reproducibility Variation in the average of the measurements made by different appraisers using the same measurement system.

5. What is GR&R? Measurement Systems Analysis GRRRRRRR!!!  2 T =  2 p +  2 m  2 T = Total Variance  2 p = Process Variance  2 m = Measurement Variance How good is our measurement system?

6. Observed Process Variation Actual Process Variation Measurement Variation Long-term Process Variation Short-term Process Variation Variation within a Sample Variation due to Operators Variation due to Gage Accuracy Repeatability Stability Linearity Reproducibility Possible Source of Variation

7. Types of Measurement Error that Affect Location

8. Types of Measurement Error that Affect Spread

9. Gauge R&R Allows Control of the Measurement System

10. Variable Gauge R&R - What’s Involved? 1 Gauge 3 Appraisers 10 Parts

11. How to set up a Variable GRR Study Preparation & Planning 1 Gauge 3 Operators (Appraisers) 10 Parts 3 Trials Randomize the readings Code the parts (blind study) if possible 3 Ops x 10 parts x 3 trails = 90 Data Points 4 Ops x 10 parts x 3 trails = 120 Data Points

12. Minitab Gage R&R Graphical Output The number of distinct categories of parts that the process is currently able to distinguish (Must distinguish at least 5 types of parts)

13. Acceptability Criteria R&R Indices  10%Acceptable Measurement System 10% - 30%May be acceptable based upon application, cost of measurement device, cost of repair, etc.  30%Not acceptable. Measurement system needs improvement. Number of Distinct Categories Index 1Unacceptable. One part cannot be distinguished form another. 2-4Generally unacceptable  5Recommended Module 0025

14. Minitab Gage R&R Graphical Output

17. Minitab Gage R&R Statistical Output

19. Questions? Comments?