An automated manufacturing analysis of plastic parts using faceted surfaces

In this paper a new methodology of automated demoldability analysis for parts manufactured via plastic injection molding is presented. The proposed algorithm uses as geometric input the faceted surface mesh of the plastic part and the parting direction. Demoldability analysis is based on a sequential model to catalog nodes and facets of the given mesh. First, the demoldability of nodes is analyzed, subsequently, from results of previous nodes analysis, facets of the mesh are cataloged in: demoldable (facets belong cavity and core plate), semi-demoldable (plastic part manufactured by mobile mechanisms, side cores) and non-demoldable (plastic part not manufacturable). This methodology uses a discrete model of plastic part, which provides an additional advantage since the algorithm works independent of the modelling software and creates a new virtual geometry providing information on its manufacture, exactly like CAE software. All elements of the mesh (nodes and facets) are stored in arrays, according with their demoldability category, with information about their manufacture for possible uses in other CAD/CAE applications related to design, machining and costs analysis of injection molds.