Measurement plays a significant role in Six sigma program. Usually, the gauge repeatability and reproducibility (GR&R) study needs to be conducted prior to the process capability analysis for verifying the accuracy of measuring equipments and helping organizations improve their product and service quality. Therefore, how to ensure the quality of measurement becomes an important task for quality practitioners. In performing the GR&R study, most industries are using the acceptance criteria of Precision to Tolerance(P/T) ratio as stipulated by QS9000. However, the adequacy of applying the same acceptance criteria to different manufacturing processes is very questionable. In this paper, a statistical method using the relationship between GR&R and process capability indices is proposed for evaluating the adequacy of the acceptance criteria of P/T ratio. Finally, a comparative analysis has also been performed for evaluating the accuracy of GR&R among three methods (ANOVA, Classical GR&R, and Long Form). Hopefully, the results of this research can provide a useful reference for quality practitioners in various industries.
Six sigma program gauge repeatability and reproducibility precision to tolerance (P/T) ratio ANOVA classical GR&R method long form method