Optimization by the taguchi method of effect on the surface roughness of cryogenic treatment applied to cutting tools

In this study, the effects on the surface roughness (Ra), cutting force (Fc), tool wear and microhardness of the deep cryogenic treatment (DCT) applied to carbide cutting tools in the machining of the AISI O2 (DIN 1.2842) cold work tool steel were investigated. However, the cutting parameters giving the optimum Ra and Fc are determined by the Taguchi optimization method (L16-43). Coated (MT-TiCN+Al2O3+TiN) and uncoated (WC+Co+TiC+TaC) carbide tools were used in the experiments. Finally, microhardness measurements have shown the effect of cryogenic process on hardness. The optimum results for surface roughness were obtained with a cryogenically-treated uncoated carbide cutting tool at a cutting speed of 250 m/min and a feed rate of 0.08 mm/rev. According to ANOVA results, the most effective parameter on the surface roughness was found to be the feed rate (80.20 %), followed by the cutting tool type (12.98 %) and the cutting speed (5.86 %). The parameters giving the lowest cutting forces were found to be cryogenically treated coated carbide cutting tool, 250 m/min and 0.08 mm/rev for cutting tool type, cutting speed and feed rate, respectively. According to the ANOVA results for Fc values, the most effective parameter on cutting force was found to be the feed rate of 85.70 %. Then, the cutting tool type is listed as 7.94 % and the cutting speed with 4.60 % as the least effective parameters. In terms of tool life, the cryogenic process has shown positive results both in uncoated and coated carbide cutting tools. In this context, 15 % and 11 % improvement was achieved in uncoated and coated-carbide cutting tools, respectively. According to the results of the Rieltveld analysis, it was determined that the carbide percentages increased in both tool groups after the deep cryogenic treatment. As a result of microhardness measurements, the hardness of uncoated and coated carbide sets after cryogenic treatment increased by 4.6 % and 5.15 %, respectively.