Study on the hot isostatic pressing post-treatment of FDM-3D printed continuous carbon fiber reinforced composites

The use of continuous carbon fiber reinforced composites (CCFRC) in fused deposition modelling (FDM)-3D printing can significantly improve the mechanical properties of products. However, compared with the products of traditional fiber placement technology, the mechanical properties of FDM-3D printed CCFRC have a big gap. In this paper, finite element analysis (FEA) and Tsai-Wu failure criterion were used to simulate the interlaminar shear failure and tensile failure of the model with staggered arranged polyamide 6 (PA6) layers and continuous carbon fiber (CCF) layers. The post-treatment processes of CCFRC were also simulated. The FEA models were FDM-3D printed and hot isostatic pressing (HIP) post-treated with the aim of improving the mechanical properties of the CCFRC. The effects of various HIP parameters including temperature, pressure and post-treatment time on interlaminar shear strength (ILSS) and tensile strength were studied. It was found that the ILSS and tensile strength were increased maximally by 64.47 % and 27.55 % under HIP as compared to the pristine samples. The mechanical properties of CCFRC after HIP treatment can be further improved compared with annealing treatment without pressure. Studying the variations in isostatic pressure and selecting the optimal pressure level to achieve the most effective enhancement can offer a novel approach for post-treatment FDM-3D printing.