Numerical and Experimental Investigation of Rheodrop Technology

A novel invention to advanced hot runner-based injection molding called Rheodrop technology is introduced. The technology allows control over the melt rheology inside the hot drops during/between injection molding cycles. The concept is to rotate the valve pin inside the hot drop to apply a controlled shear rate to the polymer melt. Doing so eliminated the incomplete filling defects associated with molding thin-walled parts and allowed processing at a lower melt temperature. The applied shear stress by Rheodrop technology was investigated utilizing ANSYS fluent software. The maximum shear stress that the polymer gets exposed to during the injection molding cycle was specified using Moldflow software. The results showed that the Rheodrop applies less shear stress than what the polymer gets exposed to during the injection molding cycle. Thus, utilizing Rheodrop does not cause additional damage to the polymer melt. Rheometric analyses were performed to investigate the polymer degradation for ABS. The reduction rate of viscosity was the same for samples that were injection molded conventionally and samples that were molded using Rheodrop technology.