Technological and Sustainability Implications of Dry, Near-Dry, and Wet Turning of Ti-6Al-4V Alloy

Titanium-based alloys are commonly applied in high-performing structural components. Their machinability could be penalized by severe tool wear and poor surface quality. As a result, cutting fluids are widely used to improve the production rate without negatively affecting the machined surface integrity and the tool life. The experimental research activities presented in this paper are focusing on the effects of dry and near-dry cutting conditions on machining process performance when turning Ti-6A1-4V. Minimum Quantity Cooling/Lubrication systems have been exploited to supply low cutting fluid volumes to the cutting area in the form of a precision metered droplets mist. The conventional flood cooling (i.e., wet cutting) has been assumed as benchmark. Results are discussed with respect to tool wear/life, cutting forces, process power demand, surface quality, lubricoolant consumption, and human health hazards. All the main factors of influence are highlighted, and guidelines for identifying the trade-off between the minimization of environmental impact and the enhancement of process productivity are proposed.