An Assessment Approach for Process Capability in Simple Linear Profile

Abstract

Process capability assessment is important to statistical quality control. The existing univariate or multivariate process capability indices cannot be directly applied to assess the process for the quality characterized by a simple linear profile. There has been little attempt to study the process capability assessment in simple linear profile. This paper proposes a method to assess process capability for simple linear profile. Since two-dimensional predictions of the slope and the intercept of simple linear profile can represent the prediction profile, the process capability analysis can be treated as a two-dimensional correlated variables problem. Then, a multivariate process capability index based on a vector of three components is applied to assess the process capability in simple linear profile. The proposed method was proved by a simulation study.