Development of a rapid thermal cycling molding with electric heating and water impingement cooling for injection molding applications

摘要

A rapid thermal cycling molding (RTCM) technology with electric heating and water impingement cooling is developed. To illustrate the feasibility of this technology in injection molding, a RTCM mold for cover plate is constructed. Experimental measurements and numerical simulations are conducted to evaluate the mold thermal response. The results show that the desired characteristics of high mold heating and cooling efficiencies are achieved. A new cavity insert-fixing mode is proposed to alleviate the thermal stress in cavity insert. It is found that the maximum thermal stress can be reduced by 75% for the constructed RTCM mold with the new mode, which is expected to result in greatly improved mold fatigue life. The surface quality of both polycarbonate (PC) and 20% glass fiber-reinforced PC (CF-PC) cover plates molded using the developed RTCM technology is dramatically improved and the surface defects that usually occur in conventional injection molding (CIM) process are eliminated. Meanwhile, the molding cycle time is not significantly increased for the RTCM process in comparison to the CIM process. So the feasibility of the RTCM technology developed for injection molding applications is successfully demonstrated. (C) 2014 Elsevier Ltd. All rights reserved.