Experimental investigations of ceramic machining using μ-grinding and μ-rotary ultrasonic machining processes: A comparative study

Comparative experimental investigations of mu-grinding and mu-rotary ultrasonic machining (mu-RUM) were made on borosilicate and Zerodur materials to know the efficacy of the processes for micro electro mechanical system (MEMS) application. The electroplated diamond tool of O 300 mu m for drilling operation and O 300 mu m to O 6mm for milling operation has been tried in the computer numerical control (CNC) machine with an HSK63 ultrasonic actuator. A suitable interface has been developed to hold the micro tool with the ER11 taper in the existing ER20 collet ultrasonic tool holder. Cutting force, edge-chipping area, and taper in drilling operation; and surface finish, material removal mode, specific energy and un-deformed chip thickness in milling operation were evaluated for both processes under the same material removal rate conditions. The experimental results showed that mu-RUM could perform in a less spindle speed machine as compared to mu-grinding. It was inferred that the maximum and minimum amount of reduction in cutting force, edge chipping, and taper were found to be (49.3%, 10.8%), (87%, 40%), and (95.56%, 4.76%), respectively, in mu-RUM compared to mu-grinding for drilling operation. It was also concluded that surface finish and ductile mode of fracture were higher in mu-RUM compared to mu-grinding for the milling operations. These effects were more pronounced as tool size decreased.