A computer assisted process planning system based on optimization criteria compromises

A high level process planning methodology has been formalized and implemented in an expert system with algorithmic kernels. An integrated sequencing and set-up selection approach based on precedence constraints and optimization criteria was developed. The system is designed so that the user follows the different steps of the process plan generation, and interacts, if needed, in the decision-making. A part is described using two types of form features: independent principal features and dependent secondary features. A set of manufacturing features is then associated to each form feature. They are then sequenced according to a set of optimization criteria hierarchically ordered, and according to their relative antecedence. The final sequence yields a compromise between the optimization criteria. The range of parts processable by the system with a minimum of user interaction covers axisymmetric parts with dominant turning operations. The system was validated using academic as well as industrial examples of axisymmetric parts.