Design sensitivity analysis and optimization for polymer sheet extrusion and mold filling processes

A polymer processing design methodology is presented which can be used to improve the production of plastic components manufactured via extrusion and injection molding processes. The design method combines polymer process modelling, design sensitivity analysis and numerical optimization. It is applicable to systems with creeping flow of purely viscous non‐Newtonian fluids through thin cavities where the lubrication approximation may be applied. An analysis and an adjoint design sensitivity analysis are presented for the steady‐state coupled system which describes the pressure and residence time distributions in sheeting dies. The resulting methodology is then used to define the optimal die cavity shape and relevant process parameters in a sheeting die design example. A second example considers tooling and process design for the polymer injection molding process. A coupled transient mold filling analysis and design sensitivity analysis based on the direct differentiation method are developed where attention is given to describing the location of the gates in the mold cavity. The latter is illustrated through the process design of a plastic automotive component.