Undercut feature recognition in an injection mould design system

In the design of plastic injection moulds, the presence of undercut features would affect mould cost and structure. In this paper, the definition, classification of undercut features and the related notions to identify them are presented. Based on the proposed undercut feature definition and taxonomy, the relationships between the undercut features and their mouldability are described. The definition of undercut feature parameters and the computational methodologies to determine them are proposed. The undercut feature draw range and directions are introduced based on the V-maps of undercut features. The recognition criteria from which the undercut features call be identified are presented. In consideration of blending surfaces, two pairs of notions, viz. actual and virtual first adjacent surfaces, actual and virtual edges are proposed. As undercut features can be consistently recognized, the identification criteria far undercut features are given. The industrial case studies show that the methodologies developed are efficient in recognition and extraction of undercut features in complex injection moulded parts. (C) 1999 Elsevier Science Ltd. All rights reserved.