An experimental investigation of surface roughness produced by micromilling of Ti6Al4V alloy under different lubrication and cooling conditions

Micromilling is a suitable method for fabrication of miniature parts with 3D complex geometries. This method has wide applications in fabricating of medical micro tools. Titanium alloys were used in medical applications extensively due to their high strength-to-weight ratio, corrosion resistance and biocompatibility. Owing to the fabricating of micro parts in implants and medical tools, studying the micromilling of titanium alloys becomes more important. In this study, the surface roughness produced by micromilling of Ti6Al4V alloy is investigated. Spindle speed, feed rate and axial depth of cut have been considered as cutting parameters. Micromilling has been done with three lubricating and cooling conditions: dry, wet and minimum quantity lubrication (MQL). TiAlN coated carbide micro-end mill tool with the diameter of 0.5mm were used. Taguchi method has been used to design and analyze the experiments. The results showed that the surface roughness is minimized by the use of the minimum quantity of lubricant. Surface roughness decreased with the increase in cutting speed and feed, regardless of the lubrication and cooling condition. The minimum surface roughness was 118 nm in the condition of spindle speed= 30000 rpm, feed rate= 0.8 µm/tooth and depth of cut= 60 µm.