A Factor-Analysis Method for Diagnosing Variability in Mulitvariate Manufacturing Processes

In many modern manufacturing processes, large quantities of multivariate process-measuremen t data are available through automated in-process sensing. This article presents a statistical technique for extracting and interpreting information from the data for the purpose of diagnosing root causes of process variability. The method is related to principal components analysis and factor analysis but makes more explicit use of a model describing the relationship between process faults and process variability. Statistical properties of the diagnostic method are discussed, and illustrative examples from autobody assembly are provided.