OBRABOTKAMETALLOV MATERIAL SCIENCE Том 23 № 3 2021 EQUIPMEN . INSTRUM TS Vol. 7 No. 2 2025 Fig. 11. Comparison of variation of thrust force (Fx) with cutting speed (Vc) and SiC volume fraction in drilling Fig. 12. Comparison of variation of torque (T) with feed rate (f) and SiC volume fraction in drilling exceptional thermal conductivity and high lubrication capacity. Graphene oxide nanoparticles mixed with Undi oil as an additive can significantly increase thermal conductivity and lubrication, leading to reduced cutting forces. NMQL significantly reduces thrust forces compared to MQL due to friction reduction at the contact face caused by the rolling effect of nanoparticles and superior cooling performance [16]. Overall, thrust force is minimum at lower SiC volume fraction (10 %) and maximum at higher volume fraction (30 %). Fig. 12 shows that at 10 % SiC volume fraction, both MQL and NMQL give similar torque results. At 20 % SiC, MQL gives lower torque values. At 30 % SiC, NMQL performs better; this torque reduction may be due to enhanced lubricity from sliding graphene oxide particles in the cutting fluid [17]. Maximum torque values are obtained at intermediate cutting speeds. Torque reduction is attributed to improved lubrication and cooling by the nanofluid. Lower torque during NMQL drilling is due to enhanced thermal conductivity and heat transfer coefficient [19]. Fig. 13 shows NMQL produces less burr height compared to MQL. High temperatures generated during MQL increase material ductility, producing larger burrs. Overall, burr height is minimum at 10 % Vf and maximum at 20 %. During drilling, heat commonly accumulates at the final machining step due to BUE formation as the tool penetrates deeper, affecting exit hole surface quality. NMQL minimizes burr formation due to enhanced heat transfer in the cutting zone. BUE formation and tool wear are also reduced, leading to less burr [16]. Burr height correlates with thrust force and torque, which decrease greatly under NMQL. Fig. 14 shows that at 30 m/min cutting speed, MQL performs better, but at other speeds NMQL gives better results for 10, 20, and 30 % SiC volume fractions. Under NMQL, nanocutting fluid reduces temperature more than MQL due to improved thermal conductivity from graphene oxide nanoparticles. Combined lubricating action reduces friction between chip and tool-workpiece interface, aiding smooth sliding. Overall circularity is minimum at 10 % and maximum at 30 % SiC volume fraction [20].
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