Automatic extraction of machining primitives with respect to preformed stock for process planning

Machining features used to identify machining regions/surfaces in a part are usually defined with respect to regular stock such as billets or blocks. These machining features cannot be used for identification of the machined surfaces/machining volumes when the part has to be machined from a preformed stock such as forging or casting. Machining primitives are proposed as the building blocks for representing the volume of material to be removed by machining. As each primitive is associated with a machining operation, it is believed that process-based reasoning will become simpler. This paper describes an algorithm to identify and extract machining primitives when the part has to be obtained from preformed stock. Results of implementation are presented.