Effect of WEDM parameters on material removal rate and kerf’s width of cobalt chromium molybdenum using full factorials design

Abstract

The use of non-conventional process for machining superalloys provides a better alternative compared to conventional machining. Conventional tool oriented processes like CNC machining demands higher manufacturing cost resulted from higher tool wear rate. In contrast, modern machining processes like Wire Electro-Discharge Machining (WEDM) eliminates such cost by offering contactless machining. This research investigated the effect of WEDM machining parameters, namely pulse-on-time (Ton, 2 µs–6 µs), pulse-of-time (Toff, 10 µs–30 µs), and peak current (Ip, 10A–14A) on the material removal rate (MRR), kerf’s width and surface integrity when machining cobalt chromium molybdenum (CoCrMo). Design of Experiment (DOE) with experimental runs of 11 full factorials design was deployed to determine the optimum parameter interaction. The result was analysed using analysis of variance (ANOVA) and mathematical models were developed to determine the relationship between the machining parameters and process performance (MRR and kerf’s width). Confirmation tests were then performed to ensure the adequacy of the result. It was found that the most significant parameter that affected both MRR and kerf’s width was pulse-on-time (Ton). The optimum result could be achieved when pulse-on-time (Ton) was set at a high level (6 µs) for MRR and low level (2 µs) for kerf’s width.