Geometric aspects of the mouldability of parts

Abstract

The mouldability of an injection moulded or die-cast component depends on various factors. In particular, the shape of the part determines the existence of undercuts in the mould parting direction. Based on the concept of blockage in a given direction, a subdivision technique is developed to evaluate the geometry of an undercut. With the notion of internal and external undercut, the mouldability of a component is studied. External undercuts can be resolved with side cores while internal undercuts can be resolved by the use of split cores. However, the use of split cores requires considerations as to whether sufficient space is available for their movement. A local and a global blockage test are introduced to detect any interference between the moulded component and a side core or a split core. A search strategy is also developed for selecting a suitable combination of main parting, side core and split core directions.