Temperature-dependent cutting physics in orthogonal cutting of carbon fibre reinforced thermoplastic (CFRTP) composite

The global commitment towards reducing carbon emissions drives the implementation of sustainable carbon-fibre-reinforced-thermoplastic composites (CFRTPs). However, the machining of CFRTPs presents challenges due to the material's ductile-brittle composition and sensitivity to machining-induced high temperatures. For the first time, we conducted temperature-controlled orthogonal cutting of CFRTP (using CF/PEKK as a demonstrator) to unveil its temperature-dependent cutting physics. Three representative cutting temperatures, 23 degree celsius (ambient temperature),100 degree celsius (T-g) and four typical fibre cutting orientations (0 degrees, 45 degrees, 90 degrees, and 135 degrees) have been investigated. The evolution of chip microstructural morphology and surface/subsurface damage have been analysed by advanced microscopy to reveal temperature-dependent material removal mechanisms. The experimental results were elucidated through a novel microscale finite-element-analysis (FEA) model considering thermal softening of the matrix and interface. Results show the transition of the cutting physics with increasing temperature is associated to the degradation of the thermoplastic matrix stiffness/ultimate strength and interface bonding strength and fracture toughness, especially when > T-g.

Automated summary

The global commitment to reducing carbon emissions has led to the use of sustainable carbon-fibre-reinforced thermoplastic composites (CFRTPs). When machining CFRTPs, challenges arise due to their ductile-brittle composition and sensitivity to high temperatures. This study conducted temperature-controlled cutting experiments to investigate the temperature-dependent cutting physics of CFRTPs and analyzed the microstructural morphology and damage using advanced microscopy. The experimental results were further explained using a finite element analysis model considering thermal softening.