Investigation of machining rate and roughness for rotary ultrasonic drilling of Inconel 718 alloy with slotted diamond metal bonded tool

Super alloy has extensive engineering applications in nuclear industries owing to its outstanding performance characteristics at elevated temperature. More than 30% of consumption in nuclear industries is super alloy. A number of holes are required to be drilled into super alloys for their final stage assembly. During conventional machining process, excessive heat is generated, which is the cause of heat treated zone that further affect the life and performance of the product. To overcome this difficulty, a rotary ultrasonic machining method came into existence to machine super alloys by hybrid cutting action (vibratory and rotary) of diamond impregnated core drill. This study focuses on the machining characteristics of super alloy by RUM process. The empirical modelling of process parameters of RUM is carried out for super alloy (Inconel 718) using an experimental design approach called response surface methodology. Material removal efficiency of RUM and surface topography of the machined material are studied. The results reported that for quality and productivity aspect, the feed rate in RUM is found a most critical factor. [Received 5 April 2017; Revised 10 June 2017; Accepted 26 June 2017]