Study of the Heat-Assisted Milling of Ti–6Al–4V Under Dry and Minimum-Quantity-Lubrication

In the present study, a pre-heating process was employed on Ti–6Al–4V alloy to overcome the machining difficulties in milling and the influence of the pre-heating on surface roughness, vibration, power consumption, and cutting tool wear was investigated. The experiments were conducted based on a Taguchi L18 orthogonal array at room temperature, hot, and hybrid cutting environments. A finite element analysis (FEM) was used to predict the temperature field on the surface of the workpiece during the hot machining of the Ti–6Al–4V alloy. The optical evaluation and microhardness measurements were carried out to determine the effect of the open flame preheating process on the machined surface and subsurface. The results revealed that a reduction of 106% and 64% in vibration and power consumption was achieved in the hybrid milling compared to dry milling, respectively. The mean tool wear was measured as 0.06 mm in the hybrid milling whereas the mean tool wear was 0.35 mm in the dry milling. Surface roughness was slightly worsened by a 15% rate due to the adhered materials particles on the machined surface in the hot and hybrid milling. The grain sizes and microhardness on the machined surfaces were not negatively affected by the pre-heating process.