Shape analysis and injection molding optimization Guy Courbebaisse a, * , David Garcia b a ESP––Ecole Sup erieure de Plasturgie, 85 rue Henri Becquerel, Bellignat 01100, France b PEP––P^ ole Europ een de Plasturgie, 2 rue Pierre et Marie Curie, Bellignat 01100, France Abstract Shape analysis is presented as a new approach towards optimization of polymer injection molding. Taking in consideration shape parameters such as optimal centering and skeleton transformation, the objective is to estimate the best location of the injection points to obtain lowest injection pressure and balanced filling of the mold. This paper concerns recent progress in the formulation of this problem. Ó 2002 Elsevier Science B.V. All rights reserved. 1. Introduction In the polymer injection-molding domain, in- dustrial requests concern the problems of optimi- zation, which need heavy computations to evaluate optimal parameters. In order to gain time, we offer an innovative approach which allows optimization of fluid injection in matrices. Optimization is here viewed in the sense of best positioning of the injec- tion points. Wegiveanoverviewofourapproach,whichcan be divided in two ways. The first one is the flow modeling based on Hele–Shaw equations [1] and the volume of fluid method (VOF) [2]. The second one is the geometrical characterization of the mold geometry by using mathematical morphol- ogy transformations in order to extract shape pa- rameters. As a consequence, we firstly introduce the flow model matched to the numerical simulation of the filling phase taking place during the injection molding cycle [1,3]. Secondly, we explain the mean- ing of optimal centering and skeleton transfor- mation in order to characterize the mold geometry. Finally, our interpretation of the results leads to a better understanding of the complex interactions between the mold geometry and the flow charac- teristics. Hereafter, we describe the three main prob- lematic which are linked to the location of the injection points inside the mould (Fig. 1): • The cavity balance to obtain a homogeneous fill- ing. • The minimization of the final injection pressure to minimize the clamp force. • The limitation of the weld lines make up. The presented work is focused on the first two points, where the goal is to find links between the Computational Materials Science 25 (2002) 547–553 www.elsevier.com/locate/commatsci * Corresponding author. E-mail address: courbebaisse@esp-oyonnax.fr (G. Courbe- baisse). 0927-0256/02/$ - see front matter Ó 2002 Elsevier Science B.V. All rights reserved. PII:S0927-0256(02)00333-6