Machining of titanium alloy using ultrasonic micro milling and nano coolant

In this study, the effects of different cooling/lubrication techniques and process parameters on the performance characteristics, namely the machinability of Ti6Al4V alloy, were investigated experimentally, numerically and statistically in conventional and ultrasonic micro milling of Ti6Al4V alloy. In the study, the effects of independent variables on workpiece surface roughness, surface topography, machining temperature, cutting force, tool wear/life, chip form, chip thickness ratio and machining index were determined in order to determine machinability. Experimental studies, under machining conditions such as rotation speed of 20,000, 40,000 and 60,000 rpm, constant feed of 0.66 mm/s and constant depth of cut of 0.02 mm, dry machining using uncoated carbide and TiSiN coated carbide cutting tools, borax-ethylene with nano Al2O3 particle additives. glycol mixture and olive oil-borax-ethylene glycol mixture was carried out using the minimum amount of lubrication (MMY) method with nano-cutting fluid containing Al2O3 in size. In ultrasonic micro milling, two different vibration frequencies (20 and 30 kHz) with two constant amplitudes were applied to the cutting tool. Cutting force and machining area temperature analysis were performed with the help of DEFORM package program. The data obtained from the experiments and the DEFORM analysis results were compared. Analysis of variance (ANOVA) was performed to determine the significance of the effects of independent variables on dependent variables. According to the experimental study results; It was determined that the vibration applied to the cutting tool improves the surface roughness, reduces cutting forces and cutting tool wear in all conditions. It was observed that the machining zone temperature increased more with the increase of cutting speed in ultrasonic micro milling performed under dry machining condition than in conventional micro milling. However, the increase in machining zone temperature in ultrasonic micro-milling experiments performed with the MMY method was quite limited compared to dry machining. In addition, with the increase of vibration frequency, the workpiece surface roughness and cutting force decreased. While flank wear was common in TiSiN coated cutting tools, no regular wear was observed in uncoated carbide cutting tools, but tip fractures, notch wear and chip coating on the tool were common. According to the surface topography results, the traces formed due to progress in conventional micro milling formed the dominant surface texture, while the formation of micro indentations and protrusions was observed in ultrasonic micro milling. While discontinuous chips were formed at low cutting speed, interrupted chip forms were seen in conventional micro milling and ultrasonic micro milling with increasing cutting speed. It was determined that the machining index of ultrasonic micro milling was higher than conventional micro milling. In the finite element analysis, the cutting temperature and shear forces were obtained very close to the data obtained in the experimental studies. According to the variance analysis results; It was determined that the most important independent variable affecting the surface roughness, cutting temperature, cutting force and chip thickness ratio was the cooling method, the independent variable affecting the tool wear was the cutting speed, and the most important independent variable affecting the machining index was the machining method