O uso dos índices Cpk, Cpm e Cpmk para monitorar processos

Abstract

The Cpk, Cpm and Cpmk indices was originally created to measure the ability of the processes to produce products meeting specifications but, more recently, they have also been used to control processes. In these new applications of the Cpk, Cpm and Cpmk indices, the specification limits are no longer limits that decide whether the item is conforming or nonconforming, they are tunning parameters that increase or decrease the speed with the control charts signal process changes in the mean and/or the variance. Therefore, this research proposes the use of control charts using the three process capability indices as an alternative to the traditional charts 𝑋̅ e R Through the Monte Carlo simulation, it was that the Cpk, Cpm and Cpmk control charts are great alternatives to the use of the joint 𝑋̅ and R charts, due they signal faster mean shifts, variance increases, and also combined mean shifts with variance increases.