Performance comparison of selected rapid heat cycle molding systems and models for predicting heating and cooling behavior

Rapid heat cycle molding (RHCM) continuously gains importance in achieving high grade polymer surface finishes. To examine the performance of selected RHCM systems, a new test mold, using two RHCM technologies, was used. The mold's nozzle side is equipped with the areal heating and cooling technology BFMOLD®, which tempers a chamber below the cavity by using hot and cold water sequentially. A local electrical ceramic heating element (Ultramic®) is installed into the ejection side, 3 mm below the cavity surface. To examine the performance of both RHCM systems a central-composite Design of Experiments (DoE) was developed. Low and high temperatures of the RHCM systems were systematically varied within the DoE. The mold surface temperature responses on both, the moving and the fixed mold half, were transiently recorded using Type K thermocouples. Polynomial models and response surfaces for characterizing the heating and cooling performance of the used RHCM systems were obtained. These models allow the prediction of the heating rate as well as the cooling speed at arbitrary temperature levels of cooling- and heating-temperatures.