Experimental Investigation and comparative study between ECDM and PMECDM of CFRP composites

Abstract Composites made of carbon fiber reinforced polymer (CFRP) are an advanced category of materials recognized for their outstanding attributes, including low density and high load-bearing capability. Due to these characteristics, CFRP composites find extensive applications in industries like biomedical, sports, aerospace, and automotive. However, machining CFRP using electrochemical discharge machining (ECDM) presents challenges, including delamination, excessive overcut, and low material removal rate (MRR). To address these issues, powder-mixed electrolyte processes, such as powder-mixed electrochemical discharge machining (PMECDM), have gained popularity. PMECDM has been shown to enhance machining outcomes for CFRP, leading to improved MRR, reduced overcut, and better surface quality. Experiments were conducted using an L16 orthogonal array, considering four key input parameters like concentration of electrolyte, tool rotational speed, Tool Travel rate (TTR), and duty cycle. Results indicated that PMECDM outperformed conventional ECDM, with MRR improving by 15% and overcut decreasing by 8%. To optimize machining parameters for the best output characteristics, the TOPSIS-Entropy method was employed. The optimal settings for maximizing MRR and minimizing overcut were identified as 35% electrolyte concentration, 480 RPM tool rotation, 90% duty cycle, and a tool feed rate of 1.0 mm min −1 . Additionally, SEM examination of the hole wall surfaces and machined holes confirmed that PMECDM machining produced CFRP composites with a smoother and cleaner surface finish.