The implementation of a feature-based component representation for CAD/CAM integration

Recent research and development has the objective of increasing productivity and cost effectiveness by integrating many activities such as design, analysis, process planning, assembly planning and production planning which encompass the entire manufacturing planning and operational control aspects of a manufacturing enterprise. It has been recognized that a key to the integration lies in the determination of a representation scheme for products that can be interpreted for the various needs of these different applications. Geometric (solid) modellers were regarded by many researchers as the appropriate representation, but more recently a features approach has been proposed to enhance the capabilities of solid modellers. This paper introduces ongoing research which is aimed at the development of a feature-based design system for process planning. The system is fully integrated with a conventional boundary representation (Brep) modeller which enhances its modelling capabilities in representing, editing and validating features of components. The main aspects of the feature-based design system are described in detail, such as the feature library, feature taxonomy, feature operations, feature relationships and tolerances. The generation of a detailed data model for transmission to manufacturing planning activities is also described and demonstrated by reference to an example component. A brief indication is given of our parallel research work in using such models as the basis of process planning and process capability modelling.