Proceedings of the
9th International Conference of Asian Society for Precision Engineering and Nanotechnology (ASPEN2022)
15 – 18 November 2022, Singapore
doi:10.3850/978-981-18-6021-8_OR-13-0244
Investigation of Conformal Heating Capability of a Curved Mold Using CNT Film Heater
1Department of Mechanical System Design Engineering, Seoul National University of Science and Technology, 232, Gongneung-ro, Nowon-gu, Seoul, Republic of Korea
ABSTRACT
In injection molding, hot polymer melt fills a mold cavity and is solidified during the subsequent cooling process. the mold temperature should be kept high to improve flow characteristics during the mold filling stage, it should be kept low to reduce cooling time during the cooling stage. In order to satisfy these conflicting objectives, rapid mold heating technology has been developed to raise mold temperature without a significant increase in the cycle time. While the conventional rapid heating technologies have focused to increase the heating speed, temperature uniformity on the mold surface has also been an important issue to improve the quality of molded parts. This study aims to develop conformal mold heating technology that uses a carbon nanotube (CNT) film heater. The CNT film heater is used to heat a curved mold with high temperature uniformity, by maintaining a uniform distance from the mold surface. The developed CNT heating technology is then applied to the conformal heating of a curved mold. Electric-thermal coupled finite element analysis (FEA) is conducted to investigate the heating characteristics of the CNT heating module, and the relevant conformal heating capability is investigated by comparing to that of the conventional oil heating. The FEA results reveal that the CNT heating shows faster temperature rise and more uniform temperature distribution than the oil heating. Experimental validation is also performed to verify the FEA result, and the experimental result shows a good agreement with the FEA result. Based on the rapid and uniform heating capability, the conformal mold heating technology using the CNT film heater can be used to improve part quality and productivity in various molding processes.
Keywords: Injection Molding, Carbon nanotube film heater, Mold heating, Conformal heating, Finite element analysis
1Department of Mechanical System Design Engineering, Seoul National University of Science and Technology, 232, Gongneung-ro, Nowon-gu, Seoul, Republic of Korea
ABSTRACT
In injection molding, hot polymer melt fills a mold cavity and is solidified during the subsequent cooling process. the mold temperature should be kept high to improve flow characteristics during the mold filling stage, it should be kept low to reduce cooling time during the cooling stage. In order to satisfy these conflicting objectives, rapid mold heating technology has been developed to raise mold temperature without a significant increase in the cycle time. While the conventional rapid heating technologies have focused to increase the heating speed, temperature uniformity on the mold surface has also been an important issue to improve the quality of molded parts. This study aims to develop conformal mold heating technology that uses a carbon nanotube (CNT) film heater. The CNT film heater is used to heat a curved mold with high temperature uniformity, by maintaining a uniform distance from the mold surface. The developed CNT heating technology is then applied to the conformal heating of a curved mold. Electric-thermal coupled finite element analysis (FEA) is conducted to investigate the heating characteristics of the CNT heating module, and the relevant conformal heating capability is investigated by comparing to that of the conventional oil heating. The FEA results reveal that the CNT heating shows faster temperature rise and more uniform temperature distribution than the oil heating. Experimental validation is also performed to verify the FEA result, and the experimental result shows a good agreement with the FEA result. Based on the rapid and uniform heating capability, the conformal mold heating technology using the CNT film heater can be used to improve part quality and productivity in various molding processes.
Keywords: Injection Molding, Carbon nanotube film heater, Mold heating, Conformal heating, Finite element analysis
