A PDM- and CAD-integrated assembly modelling environment for manufacturing planning

This paper reports the development of an advanced assembly modelling environment for the purposes of manufacturing planning and analysis. computer-aided assembly process planning (CAAPP) is not a mature technology, despite the managerial and technical advantages offered by its implementation. This paper describes the limiting factors in industrial acceptance of CAAPP and discusses methodologies by which these factors can be eliminated. This is done primarily by the integration of CAAPP functionality with a product data management (PDM) tool, providing a data control framework and a high-level data structure to form the basis of planning. The paper also details a system based on the described methodologies. Data control methodologies are presented to aid retrieval, storage and creation. Methods for the definition of liaisons, mating features and fastener information are discussed. The methodologies used for constraint identification, process sequence generation and sequence representation within the system are described. Multiple sequences are represented by means of a tree structure, similar to the AND/OR graph representation. The sequence is navigable and can be used downstream to evaluate possible sequences of generate scheduling data. The underlying object-oriented model developed to facilitate automated assembly process planning is described in detail.