The effect of different MQL supply strategies into the cutting zone on the tool wear when turning of Ti-6Al-4V alloy

Titanium alloys, especially Ti-6Al-4V alloy, are widely used in industry due to their good mechanical properties, such as high specific strength and excellent corrosion resistance. However, titanium alloys are also difficult-to-cut materials. Metalworking fluids are employed in the machining process to improve the machinability of titanium alloys. In recent years much attention has been paid to the use of the minimum quantity lubrication (MQL) techniques in the machining of the titanium alloys. In this study, the tool wear and its influence on the components of cutting forces have been investigated for different MQL supply strategies into the cutting zone - MQL via external nozzle and MQL via tool holder were investigated. The obtained results were compared with dry turning. It was concluded that the mechanism of tool wear is very similar for each cutting condition, however, it was also noted that the tool life is 28% and 68% longer for the MQL via external nozzle and MQL via tool holder, respectively, compared with the dry cutting conditions.