Increasing tool life in machining of difficult-to-cut materials using nonconventional turning processes

Machining of difficult-to-cut materials such as high-temperature metals is challenging due to their low machinability resulting in reduced productivity and high manufacturing cost. Turning is a common operation used for production of these parts where cutting speed, and thus the material removal rate, is limited due to high tool wear rate. Therefore, there is a need for alternative techniques in order to increase productivity in machining of these materials. This paper presents experimental results on two nonconventional turning operations, namely turn-milling and rotary turning processes, applied on common difficult-to-cut materials. Tool wear was measured under various cutting conditions for both processes and compared with conventional turning. From test results, it can be concluded that both turn-milling and rotary turning operations can provide longer tool life compared to conventional turning, thanks to intermittent characteristics of processes which result in lower average tool temperature. Effects of cutting and cooling conditions on tool life were also investigated yielding conclusions for selection of conditions for increased tool life.