Experimental Study on Hybrid Ultrasonic and Plasma Aided Turning of Hardened Steel AISI 4140

Several methods such as plasma enhanced turning (PET) and ultrasonic-aided turning (UAT) have been introduced to assist conventional turning (CT) in order to overcome the difficulties of hard turning. There exist extensive experimental researches which have shown the feasibility of PET and UAT in hard turning. This paper investigates the cutting force and surface roughness in hybrid plasma and UAT hybird turning (HYT) on the AISI 4140 hardened steel. The studied parameters are turning parameters (cutting speed, feeding rate, and depth of cut), tool material, plasma, and ultrasonic parameters. For this purpose, a model was developed to relate current of plasma to the material removal temperature. The plasma and ultrasonic equipment were installed on the lathe, then hybrid ultrasonic and plasma aided machining was applied on AISI 4140 hardened steel for experiment using Taguchi design. Results showed the reduction of cutting forces in hybrid machining in comparison with CT, PET, and UAT; and depending on cutting conditions, workpiece surface roughness can be improved in hybrid machining in comparison with CT, PET, and UAT.