The statistical monitoring of a complex manufacturing process

This paper describes the development of a multivariate statistical process performance monitoring scheme for a high-speed polyester film production facility. The objective for applying multivariate statistical process control (MSPC) was to improve product consistency, detect process changes and disturbances and increase operator awareness of the impact of both routine maintenance and unusual events. The background to MSPC is briefly described and the various stages in the development of an at-line MSPC representation for the production line are described. A number of case studies are used to illustrate the power of the methodology, highlighting its potential to assist in process maintenance, the detection of changes in process operation and the potential for the identification of badly tuned controller loops.