Dr. Joan Burtner Certified Quality Engineer Associate Professor of Industrial Engineering and Industrial Management The Certified Quality Engineer Handbook 3 rd ed. Ch. 26: Measurement System Analysis
ISE 428 ETM 591 JMB CH 26 Lecture 2 Ch. 26: Measurement System Analysis Terms and Definitions Gage Repeatability and Reproducibility Variables vs. Attributes Gage R&R Methods Tabular Analysis of Variance Control Charts 2
ISE 428 ETM 591 JMB CH 26 Lecture 2 Philosophy of Gage R & R Studies Gage Repeatability and Reproducibility (R&R) studies are used to determine if a measurement system is capable for its intended purpose. The measurement system is considered capable if measurement system variation is small compared to the process variation. The measurement error variance equals the sum of the variance due to reproducibility and the variance due to repeatability 3
ISE 428 ETM 591 JMB CH 26 Lecture 2 Purpose of Gage R & R Studies Determine amount of variability in the collected data that can be attributed to the existing measurement system Isolate the sources of variability in the measurement system Determine whether the measurement system is suitable for use in a broader project 4
ISE 428 ETM 591 JMB CH 26 Lecture 2 Gage R &R Methods Tabular “Old method” Based on control charts Statistically incapable of quantifying interaction between operators and parts Analysis of Variance Random two-factor model See standard experiment notation on page 261 We will use Minitab to estimate variance effects We will p-values to determine significance of the main effects and the interaction between the factors 5
ISE 428 ETM 591 JMB CH 26 Lecture 2 Issues and Considerations ANOVA applies to variables data – R&R studies for attributes data beyond the scope of the CQE Handbook Standard experiment 10 parts, three operators, two replicates Replicates vs. repeated measures? Restricted randomization “There are numerous applications where complete randomization or true replication is not practical or possible.” (page 269) 6