Photo/Thermo-Curing 3D Printing of High Thermal Conductivity CFRP with Pitch-Based Short Carbon Fibers

Abstract

The thermal conductivity of the Carbon Fiber Reinforced Plastic (CFRP) can be locally controlled by regulating the carbon fiber orientation by passing them through a thin nozzle. To manufacture heat-conductive components, a novel method is proposed to print CFRP with photo-/thermo-curing resin and pitch-based short carbon fibers using 3D printing. Subsequently, CFRP with unidirectionally oriented fibers were successfully fabricated using the developed method. In addition, a thermal conductivity meter for high thermal conductivity CFRP thin sheets was fabricated, and the thermal conductivity of unidirectionally fiber-oriented, 3D-printed CFRP specimens with a fiber content of 25 and 30 vol% were measured. The anisotropy of the thermal conductivity of the CFRP samples were confirmed, and the thermal conductivity increased with increasing fiber content. At 30 vol% fiber content, the fiber-directional thermal conductivity was 14.9 W/m･K, which is equivalent to that of stainless steel. The cross-sectional observation of the samples showed that voids were formed during fabrication. These voids may have obstructed the heat transfer pathways, and thus, CFRPs with a considerably higher thermal conductivity were fabricated by reducing the void ratio.