Process Capability Analysis for Simple Linear Profiles in Two-stage Process

When a process is statistically in-control, one may be interested in assessing the pWhen a process is statistically in-control, one may be interested in assessing the process performance based on the process capability analysis. Although an extensive literature exists on process capability analysis when quality characteristic of interest is continuous or discrete but the existing methods are not applicable to the case when a process or product is represented by a linear profile. A profile is a relationship between a response variable and one or more independent variables. Manufacturing operations are often involved with multistage processes, in which the output of a stage is the input of its subsequent stage. This property is known as the cascade property. Using common indices to assess the capability may lead to incorrect results as the cascade effect is ignored. This study presents a method to conduct process capability analysis in a two-stage process when quality of a product or process can be characterized by a simple linear profile. A numerical simulation evaluates the performance of the proposed method for a two-stage process. The results indicate effective performance of the proposed methodrocess performance based on the process capability analysis. Although an extensive literature exists on process capability analysis when quality characteristic of interest is continuous or discrete but the existing methods are not applicable to the case when a process or product is represented by a linear profile. A profile is a relationship between a response variable and one or more independent variables. Manufacturing operations are often involved with multistage processes, in which the output of a stage is the input of its subsequent stage. This property is known as the cascade property. Using common indices to assess the capability may lead to incorrect results as the cascade effect is ignored. This study presents a method to conduct process capability analysis in a two-stage process when quality of a product or process can be characterized by a simple linear profile. A numerical simulation evaluates the performance of the proposed method for a two-stage process. The results indicate effective performance of the proposed method