Evaluation of process capability in multivariate simple linear profiles

Abstract

In some situations, the quality of a process or product is characterized by a linear regression model between two or more variables which is called a linear regression profile. Moreover, in some cases, several correlated quality characteristics can be modeled as a set of linear functions of one explanatory variable which is typically referred to as multivariate simple linear profiles structure. On the other hand, process capability index is an important concept in statistical process control and measures the ability of the process to provide products that meet certain specifications. Little work, however, is done to evaluate the capability of a process with profile quality characteristic. This paper proposes three new methods for measuring process capability in multivariate simple linear profiles. Performance of the proposed methods is evaluated through simulation studies. In addition, the applicability of the proposed methods is illustrated using a real case of calibration application.