Application of Numerical Analysis to One-Piece SMC Panels

Abstract

Products molded from fiber-reinforced material are subject to several problems during the manufacturing process, such as sink marks, warpage and short shots. In an earlier work the authors used finite element analysis to analyze the in-mold flow behavior of sheet molding compound (SMC) during the compression molding process. In the present work a new analytical procedure has been devised for making a detailed analysis of the flow behavior of SMC during the rib filling process. This procedure employs a combination of flow and deformation analysis techniques, a method that was used in the previous work, and also a newly added flow analysis technique at the stage just prior to the completion of filling. A numerical model has also been devised for the molding process described in the previous report, in which back pressure is applied to minimize sink marks. The model is designed so that the relationship between changes in various molding factors and the resulting severity of sink marks can be analyzed quantitatively. The results of the present work are now being used to establish a molding concept for a one-piece outer panel.