Process Yield for Multivariate Linear Profiles with One-sided Specification Limits

摘要

The new investigation of profile monitoring is focused mainly on a process with multiple quality characteristics. Process yield has been used widely in the manufacturing industry, as an index for measuring process capability. In this study, we present two indices CpuAT and CplAT to measure the process capability for multivariate linear profiles with one-sided specification limits under mutually independent normality. Additionally, two indices CpuA;PCT and CplA;PCT are proposed to measure the process capability for multivariate linear profiles with one-sided specification limits under multivariate normality. These indices can provide an exact measure of the process yield. The approximate normal distributions for CpuAT and CplAT are constructed. A simulation study is conducted to assess the performance of the proposed approach. The simulation results show that the estimated value of CpuAT performs better as the number of profiles increases. Two illustrative examples are used to demonstrate the applicability of the proposed approach. Copyright (c) 2015 John Wiley & Sons, Ltd.