05-04-2000
Implementation of Statistical Process Control in Low Volume Production EnvironmentsRemco Stam, UvA, Amsterdam, December 1994Abstract Standard quality control procedures are originally designed for use at mass production industry. However, nowadays there exists industry that is far from mass production (for instance, facilities producing equipment for space flight or semiconductor material). The nature of these low volume production environments causes many problems with basic quality control and improvement procedures: the procedures are impossible to perform, the process data needs special treatment or the probabilities attached to the control limits are larger than meant originally. In this thesis, modifications to the standard control charts are presented and new methods such as Q charts for variables are subjected to statistical evaluation. For Q charts, powerful modifications are introduced, such as lagged Q charts and QR charts. The second part of the article is on the use of process capability indices and their pitfalls. Being more general than the first part, it emphasizes the need for a thorough process capability study, instead of displaying the quality of a process or product in one or two simple indices. Keywords Statistical process control; Short Run/Small Run Control Charts; Q charts; Process Capability Indices; Process Capability Study. |
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05-04-2000 |
