Development of a modular mold with a carbon nanotube web film heater for rapid-heating cycle molding

Abstract

A new process technique called rapid heat cycle molding (RHCM) has been developed using a carbon nanotube (CNT) web film as a heat source for the mold. Although various heating technologies have been applied as RHCM techniques, low energy efficiency has caused productivity to decrease. To improve this issue, the RHCM process was implemented using a CNT web film for more efficient heating. A multilayer structure module was designed to apply the CNT web film to a full-size injection mold. The RHCM process was implemented by designing stable heat transfer and electrical insulation through a multilayer structure module. When power was applied, the temperature rose quickly, with the highest heating rate reaching 41 °C/s at 40 kW, and the highest temperature achieved at about 300 °C. The temperature uniformity and stability were tested on 6 points of the cavity surface, and an average of 97% temperature uniformity and stability was observed during heating. In production testing of the Center Fascia (CTR.FASCIA), which is an internal automobile part made of polycarbonate/polybutylene terephthalate composites, an RHCM process was conducted. The width and depth of weld lines in the molded products were eliminated, and a 26% improvement in glossiness and surface quality was observed compared to the conventional injection molding process (CIM). CNT web film is a versatile and flexible material that can be applied in various forms, and it has been confirmed that by utilizing this material to create a multilayer structure module, the RHCM process can be performed reliably.