Numerical Optimization of Polymer Die Design for Multiple Objective

How modeFRONTIER was used to apply DOE strategies, manage the automation of CFD runs, and analyze the data for optimized polymer die design

Research engineers at Dow Chemical were interested in exploring the application of recent advances in engineering optimization using commercial Computer Aided Engineering (CAE) tools for their simulation based design phase. The design of a polymer die, also known as a “coat hanger” die, was chosen as a test case for such an optimization study to improve more than one objective. The main objectives for optimization were to maximize flow uniformity of the polymer melt across the die exit while simultaneously minimizing the pressure drop. Polyflow, a commercial Computation Fluid Dynamics (CFD) code, and modeFRONTIER, optimization and process integration software, were used to optimize the design of one such coat hanger die.

Study Highlights:

  • This study has shown how CFD-based optimization can be used to improve the flow uniformity of a coat hanger die while minimizing the pressure drop.
  • Optimal solutions can be identified by increasing the number of geometric parameters that are allowed to change; however the computational cost also increases.
  • When dealing with a small number (< 5) of adjustable parameters and fairly linear responses, a simple DOE-RSM method may be adequate to identify an optimal solution in a short amount of time.
  • The FMOGA method will be more accurate than the RSM method and shows promise when 10 or fewer adjustable parameters are involved.
  • For a larger number of parameters, a direct optimization method, such as NSGA, may be the best option, although at a computational cost.