Product Family Manufacturing Plan Generation and Classification

Abstract

In the concurrent engineering approach, the problems related to product fabrication are taken into account as early as possi ble in design process. Manufacturing and assembly process design are decisive and expensive processes conditioning all the future steps of industrialisation and fabrication. In this paper a new method for assembly plan generation, based on the concept of meta-prod uct, is presented. This method is designed for modern production environments that are organised in product families with multiple op tions and variants. Facing the combinatory explosion problem, the method proposes an original representation of assembly sequences allowing the generation of a minimal list of non-redundant assembly plans called meta-sequences. In this method, an optimal assembly sequence class is selected. Then, for each product variant an optimal specific plan class is deduced from a simple analysis of product variant's components. An assembly reactive control system, adapting this optimal solution to the real assembly workshop conditions is also proposed. Another competitive problem is the case of production of old or short-series products. To rationalise their manufacturing, a solution consists in classifying products into classes, on the basis of similarity of required manufacturing processes. This technique called group technology (GT) helps to minimize unnecessary variety of products in a manufacturing plant by making designers aware of existing simi lar components. In this paper a new GT method is presented. It allows the classification of sequential manufacturing sequences as well as tree-like manufacturing plans. The method is based on an adapted representation of tree-like manufacturing plans, the distance adapted to this special case, efficient heuristics, and hierarchical bottom-up classification. Then, each product class can be managed in accordance to our family product generation method, or can be served as a base for reengineering process of firm's range of products.