A Generative Approach for Die Pattern Matching

Manufacturing a press die for car body panel usually starts from making a Styrofoam pattern (for short, ‘pattern’) for lost wax casting process. Industry trend is to build patterns by NC machining. Since the mating planes for assembly or die face of casting stock are to be machined later, pattern should have some stock allowance on those surfaces, which can be as large as 12 mm. That means pattern itself can have fairly large amount of machining tolerance compared to die machining. Styrofoam is easy to cut, but fragile. Hence, the process planning for pattern machining should reflect some different aspects than that of die machining. In this paper, presented is the generative approach taken by Chrysler to create tool path to cut pattern from the CAD model of die. The approach includes steps of 1) feature recognition, 2) automatic process planning and 3) tool path generation.