The Application of Group Technology Concept for Implementing SPC in Small Batch Manufacture

The use of Statistical Process Control (SPC) techniques for monitoring manufacturing processes in mass production is relatively easy. In small‐batch manufacture, however, such techniques can be difficult to implement due to lack of sufficient data to establish control decisions for control charts. Most of the early proposed solutions emphasized the product rather than the process, whereas many of the recently developed approaches favoured monitoring the process and not the product. All such approaches suggest the use of data transformation. The aim is to normalize the differences in the process mean and the variability for different components. Once an appropriate transformation is made, then sample data related to different components can be plotted on the same chart using sample statistics of the transformed data. An important part of transformation is the determination of process parameters for the component. Several methods for determining such parameters have already been suggested in the literature. Presents an alternative method for estimating the process parameters, based on the Group Technology (GT)concept. Generally speaking, the methodology consists of four steps,i.e. Classification and Coding (C&C), family formation, retrieving data,and estimating the process parameters. Discusses the characteristics of a C&C system for SPC and presents the details of its structure. Finally,based on the proposed structure, uses a flowchart to explain the procedure along with a practical application.