Optimizing injection gate location and cycle time for the in‐mold coating (IMC) process

Abstract The standard practice when compression molding Sheet Molding Compound (SMC) exterior automotive body panels is to in‐mold coat (IMC) the parts. Consequently, IMC needs to be considered an integral part when improving the process. Selecting the proper IMC injection gate location to obtain a defect‐free coated part and properly setting the IMC processing conditions to reduce its cycle time are both key decisions for the IMC process. In the present work, an optimization method that involves metamodeling through either linear regression or artificial neural networks is explored with two purposes: first, to select the injection gate location(s) with the objective of minimizing the potential for surface defects in the coating; and second, to set the mold wall temperature and the initiator concentration to minimize the cure time for a given minimum required flow time.