Comparison of approaches for optimizing molding parameters

Manual and software-based (automated) methods for process parameter optimization were compared for (1) methodology, (2) their ability to optimize the processing conditions for a wide variety of polymer materials, (3) the processing conditions, and (4) the quality of the resultant parts. While the two techniques had similar steps, the automated method required material, temperature, volume, and thickness inputs. The automated method also produced longer filling and packing strokes, injection velocities that rarely exceeded 25 mm/s, higher packing pressures, longer packing times, and longer cooling times. When the automated approach was tested using two molds, two machines, and eight materials, the material database and the overly low injection velocity limited the setup windows. Narrower windows occurred when the material did not match the generic polymer in the database, and the low injection rates often induced pressure-limited viscosity. Automatically optimized molding conditions produced tighter control of part weights and dimensions, but higher residual stress than comparable parts molded using manually optimized processing conditions.