Machining characteristics of Inconel 718 using ultrasonic and high temperature-aided cutting

This investigation discusses the machining characteristics of Inconel 718 by combining ultrasonic vibration with high-temperature-aided cutting. Taguchi experimental design was used to clarify the influence of various machining parameters on the machining characteristics. This study discusses six machining parameters, including cutting tool made of different materials, depth of cut, cutting speed, feed rate, working temperature and ultrasonic power. The machining characteristics studied include surface roughness and cutting force. According to the experimental results, as Inconel 718 is heated for high-temperature (190 °C) cutting, cutting becomes increasingly difficult owing to precipitating the hard secondary phase of γ″(Ni3Nb), thus the cutting force is higher than that at room temperature. Formation of built-up-edge (BUE) when using a NX2525 cermet cutter is far less than that of a TN35 tungsten carbide cutter, the surface roughness and the cutting force are lower than those for a TN35 tungsten carbide cutter. As a result, the NX2525 cermet cutter provides a more suitable cutting tool for Inconel 718. Furthermore, this investigation also found that when being aided by ultrasonic vibration in the tangential direction, it could obtain a lower surface roughness of the machined workpiece and a reduced cutting force, hence service life of the cutter was lengthened.