Effect of R410a coolant on tool wear, dimensional deviation and surface roughness in turning of AISI 1045 steel

Abstract

Friction between the tool and the workpiece during machining operations always increases the tool wear rate. Removing this problem by using fluids and cooling the tools is essential. In this research, the effects of two cooling conditions: Water Soluble Cutting Oil (WSCO) fluid and R410a coolant, on the tool wear rate, dimensional deviation and surface roughness of AISI 1045 steel (CK45) in turning with a high-speed steel (HSS) tool were investigated. The selected parameters were cutting speeds of 15, 25, 40 and 55 m/min, cutting depths of 0.5, 1 and 1.5 mm and feed rates of 0.05, 0.12 and 0.2 mm/rev. The results show that cooling by R410a coolant reduces the tool wear rate due to its high cooling power and better temperature control at the cutting zone compared to WSCO fluid. Based on the minimums of tool wear, dimensional deviation and surface roughness in different conditions, using R410a coolant can increase the cutting speed by 60% from 25 to 40 m/min. Also, in the optimal condition at a cutting speed of 40 m/min, cutting depth of 1 mm and feed rate of 0.05 mm/rev., tool wear, dimensional deviation and surface roughness are reduced by up to 20, 6 and 10 times respectively. In the optimal condition, the dimensional deviation based on the diameter difference along 300 mm is reduced to 14 µm and also the tool wear rate and surface roughness after 60 min. of turning are reduced to 20 and 3.1 µm respectively. The effect of each input variable on tool wear, dimensional deviation and surface roughness was calculated by statistical analysis and was validated by ANOVA.