Experimental investigation and comparative study between machining of CFRP composite and CNT-mixed CFRP composite using ECDM process

Carbon fiber-reinforced polymer (CFRP) composites are a class of latest materials because of their impressive properties like low density and high load-carrying capacity. CFRP composites have numerous applications in aerospace, sports, automobile, biomedical, etc. Machining of CFRP is the need of the hour, but problems, namely delamination, fiber pull out, matrix-resin debonding, workpiece damages, etc., have made it difficult. To overcome these limitations, an advanced machining process like ECDM (electrochemical discharge machining) is significantly applied nowadays. Further, the thermal and mechanical properties of the composites were improved by adding multiwalled carbon nanotubes (CNT s ) into polymer matrix composites. In this paper, experimental investigation and comparative study were performed between machining of CFRP and machining of CNT-mixed CFRP with ECDM process. Machining of CFRP results better output responses, namely MRR, overcut, and hole taper. However, machining of CNT-mixed CFRP composites yielded better surface integrity and dimensional accuracy. The experiments were performed with L 16 orthogonal array by considering the input parameters (a) electrolyte concentration, (b) tool rotation, (c) tool travel rate, and (d) duty cycle. Machining of CFRP exhibits better results by 12% for MRR, 7% for overcut, and 13% for taper in comparison with machining of CNT-mixed CFRP composites. TOPSIS-Entropy optimization technique was employed to obtain optimal parametric setting for output characteristics. The parametric combination of 25% electrolyte concentration, 360 RPM tool rotation, 1.0 mm/min tool travel rate, and 90% duty cycle resulted the optimal condition for MRR, overcut, and taper. SEM images also indicate that CNT-mixed CFRP composite exhibits smooth surface finish.