An experimental study of resistance welding of carbon fibre fabric reinforced polyetherimide (CF fabric PEI) composite material

This paper presents an experimental investigation of resistance welding of carbon fibre fabric reinforced polyetherimide composites (CF fabric/PEI). The heating elements were made from a single CF fabric/PEI prepreg sheet with neat PEI films co-moulded to both surfaces. Welding was conducted on a welding area of 25 mm x 12 mm. The quality of the welded specimens was studied using a non-destructive evaluation technique (C-scan) as well as a mechanical test (lap shear strength). The relationships between input power, input energy, welding time and consolidation pressure were studied. Experimental results indicated that sufficient joining was obtained at a power level from 80 to 160 kW/m(2), under an initial welding pressure of 0.15 to 0.40 MPa. The maximum lap shear strength achieved through resistance welding was equivalent to that of the compression moulded benchmark. The fracture surfaces of welded specimens showed mostly cohesive-failure or intralaminar failure. An optimum processing window is proposed for the resistance welding of CF fabric/PEI composite system.