Detection of interference elements and release directions in die-cast and injection-moulded components

Many interference elements may exist in a die-cast or injection-moulded component which prevent the removal of the component from a die or mould cavity. Each interference element corresponds to a direction or a set of directions along which the interference element can be released. In computer aided determination of parting direction for a diecasting die or an injection mould, the two basic problems, the detection of the interference elements and the definition of corresponding release directions, should be involved. In this paper, a three-dimensional ray-detection method is introduced to detect the interference elements. The method includes sweeping a solid model, recognizing the geometric feature and extracting the shell of the interference element. A vector plane approach is proposed to solve release directions of the interference shell. The approach uses vector planes to collect the normal vectors of the shell surface, and then the release direction of a vector plane is determined by two extreme vectors on the plane. The release directions of an interference element are obtained by intersecting the release directions of all vector planes.