A new approach to parting surface design for plastic injection moulds using the subdivision method

This paper proposes a new approach to automate the design of parting surfaces for plastic injection moulds. The new method tackles the issue of the automatic generation of a polygonal complex that is required for boundary curve interpolation. The mesh that defines the 'interior' of the surface patch is generated using medial axis transform and optimization. Upon subdivision, the mesh generates a smooth surface patch that connects to neighbouring patches to form the entire parting surface. This new method has been integrated with our previous result to develop an experimental system that automates parting surface design for a plastic part with a complex parting line. The major advantage of this new approach is that the subdivision surface is generated by a standard subdivision scheme which facilitates the development of any downstream applications, such as CNC tool-path extraction, on the surface. Examples and a design case study are presented to demonstrate the major steps and verify the feasibility of the new approach.