Process quality assessment by various methods, and the impact on them of the variability of measurement systems

The article discusses in detail two approaches to quality assessment: the traditional one, based on tolerances, and the relatively new one, based on the Taguchi quality loss function. The reproducibility indices, which are often used for assessing the quality of processes, and the influence of the variability of the measurement system on them are discussed. A practical consideration of all the issues discussed is carried out taking into account the real data of a particular production. It is shown that the Taguchi IVP has a significant advantage in terms of assessing the quality of the process in the presence of a target value. In addition, the variability of measurement systems has a significant impact on the Taguchi IWP value, and for more finely tuned and less variable processes, this effect is more significant. Based on the data of the real process, the dependence of the Taguchi loss estimate on the quality of the measurement system was revealed.