Using Control Charts to Monitor the Performance of Large-Scale Systems

Abstract

ABSTRACTThe initial goal of this project was to provide Alcan Rolled Products Company of Kingston, Ontario, with control charts to monitor its new Paint Line Three (PL3) aluminium coil coating facility. As the project progressed, however, it became apparent that the following factors made PL3 ill-suited to traditional statistical quality control methods: the inexact nature of the coil coating science, the level of process interdependence and complexity of the operation, and the economic and technical infeasibility of installing sophisticated measuring devices at all stages of the coating line.Consequently, an effort was made to model the entire system on a macroscopic, rather than a microscopic, level and to use the results of qualitative lab tests to make inferences about the paint line's process capability. To accomplish this, the length of scrap produced by every lot processed in a 1-year period was used to create a statistical model of the of the frequency and severity of the two most costly quality s...