Investigation of machining characteristics during micro-hole fabrication in CFRP composite by ECDM process

Abstract

Carbon fiber reinforced polymer (CFRP) composites have gained significant popularity in the field of aerospace, automotive, electronic, and sports due to its versatile properties. Although, fabrication of micro-holes in CFRP composite is troublesome by the conventional processes because of its anisotropic and abrasive behaviour. To overcome this difficulty, recently, an unconventional hybrid process such as electrochemical discharge machining (ECDM) is extensively used to machine such types of materials. This paper highlights the experimental and statistical analysis of machined micro-holes which was fabricated in CFRP composite using ECDM process. The experimentation was performed according to Taguchi’s L9 orthogonal array. The input parameters were (a) voltage, (b) tool rotation, (c) tool travel rate, and (d) duty cycle, each at three levels. Hole overcut and taper was measured as output responses. TOPSIS-Entropy based multi-response optimization technique was applied to optimize the chosen parameters. The hole overcut and taper was measured and analysed using SEM images. The parametric combination of 50 V, 360 RPM, 0.5 mm min−1, and 60% resulted minimum overcut and taper of 227 μm and 72 μm, respectively. The morphology of the machined hole exhibited better surface characteristics at a high tool travel rate and low duty cycle. Tool wear in terms of lateral wear and flank wear was observed during machining at high voltage and high duty cycle. From the TOPSIS Entropy analysis, the optimal condition for both overcut and taper was found as 50 V, 360 RPM, 0.5 mm min−1, and 60%.