Repeatability and reproducibility studies: a comparison of techniques

Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering.Gage Repeatability & Reproducibility (GRR) Studies have become critical in process improvement projects in the manufacturing sectors. There are various methods to conduct GRR study. However, the most widely used is the Automotive Industry Action Group (AIAG) method, which was standardized after the recognition of the importance of measurement systems. In this study, AIAG method and Wheeler’s method are compared, with specific interest in the proportions of the estimates of variation. An experimental study was designed, with factors being the operators and parts. The spectrum analyzer – Quattro, was tested for its adequacy of measurement and to understand the variability in the measurement system. In this research, vibration-impact testing was performed on Stereolithography (SL) parts and the measured feature was the natural frequency. The data was analyzed following the AIAG method and that proposed by Wheeler. From the results obtained, the Repeatability and Reproducibility were over estimated by AIAG method in comparison to Wheeler’s. The Wheeler’s method gave a better understanding of the sources of variation. Due to which, the measurement system capability could be judged without bias. Also, Wheeler’s method helps in making right decisions about the measurement system. Therefore, Wheeler’s method is strongly recommended over the AIAG