2008 Volume 16 Issue 3 Pages 86-92
At present, many manufacturers use control charts to study the stable states of their manufacturing processes. There are several problems with this, however,because a control chart evaluates a process in terms of only a single parameter. To address these problems, the MT system was applied to control charts, and the Mahalanobis distance and orthogonal arrays were put to work to study the stable state of a process, using multiple variables. The results achieved included the discovery of problems and their causes, and improved detection of abnormalities in the process and product, making it possible to detect problems even when the process was unstable.