A study of material removal and surface characteristics in micro‐electrical discharge machining of carbon fiber‐reinforced plastics

Abstract

This article presents micro electrical discharge machining (μEDM) of carbon fiber‐reinforced plastics (CFRP) with rotating tool electrode and assisting electrode (AE). The experimental investigation majorly focused on establishing the mechanisms of material removal and surface integrity of the machined blind holes. Taguchi and regression analysis were carried out to assess the material removal rate (MRR). Analysis of variance (ANOVA) was applied to understand the significance of input parameters and their contribution toward achieving maximum MRR. The surface integrity of the machined hole and damage modes of composite constituents were also examined through micrographic images. The experiments were carried out varying the voltage, pulse duration, and tool speed at three levels. The investigations showed that μEDM process can be applied for fabricating micro holes in CFRP if assisting electrode (AE) is used to initiate the spark. From the analysis of variance (ANOVA), it was observed that the percentage contribution of voltage, pulse duration, and tool rotational speed on MRR are 75.09, 5.20, and 16.09%, respectively. The optimal condition for the highest MRR was found to be V3/T1/S3 (voltage of 170 V, pulse duration of 10 μs, and tool speed of 800 rpm). The calculated value of MRR (341,264.94 μm 3 /s) at the optimum level of input parameters was found to be close to the experimental MRR (340,727 μm 3 /s). The percentage error between the experimental and calculated value of MRR at the optimum level is very low as 0.15%. This indicates that the developed statistical model is quite significant in predicting MRR during μEDM of CFRP. POLYM. COMPOS., 40:4033–4041, 2019. © 2019 Society of Plastics Engineers