Parameter optimisation of resistance welding and separation process of thermoplastic composite joints using carbon-fibre-reinforced low-melting poly(aryl ether ketone) (CF/LM-PAEK)

This study presents an investigation of both the joining and controlled disassembly of resistance-welded carbon-fibre-reinforced low-melting poly(aryl ether ketone) (CF/LM-PAEK) thermoplastic composite joints. A Taguchi design of experiments followed by analysis of variance (ANOVA) are used to explore the effects of welding time, power and pressure on lap-shear strength. Optimised welding parameters—35 s, 140 W and 0.6 MPa—produce a lap-shear strength of (50.5 1.5) MPa. Subsequent annealing at 190 C (cooling rate 5 C/min) increases strength to (63.2 1.5) MPa. Disassembly trials are carried out via resistance heating. By applying 2–3 V to the heating element, different weld-zone temperatures are generated, and the influence of temperature and cross-head speed on joint separation is assessed. An operational window for successful disassembly is identified at a traverse speed of 175 mm/min and a temperature of 285 C. Under these conditions, the joint cleanly separates into the heating element and the adherends without visible heat-induced deformation of the laminates. The residual separation force is (371 125) N, corresponding to a 98 % loss of mechanical strength. These results demonstrate an efficient cycle of welding and disassembly for CF/LM-PAEK composites, laying the groundwork for part exchange, reuse and recycling in lightweight-structure applications. • Resistance welding of CF/LM-PAEK yields (63.23 1.48) MPa lap-shear. • Disassembly window at 285 C and 175 mm/min enables clean separation. • Heating element and adherends separate with (371 125) N and no laminate deformation. • Basis for reuse, disassembly, and recycling of resistance-welded TPC structures.