PARTING DIRECTIONS FOR MOLD AND DIE DESIGN

On the basis, of the condition for demouldability, two levels of visib ility, complete and partial visibility, are defined. The viewing direc tions from which a surface is completely visible can be represented as a convex region on the unit sphere called the visibility map of the s urface. Algorithms are given for dividing a given object into pockets, for which visibility and demouldability can be determined independent ly, for constructing visibility maps, and for selecting an optimal pai r of parting directions for a mould that minimizes the number of cores . An example illustrates the algorithms.