en فرایندهای تولید و سیستم ها Manufacturing Process & Systems پژوهشي Research <div style="text-align: justify;"><span style="font-size:11pt"><span new="" roman="" style="font-family:" times=""><span style="font-size:11.5pt">Improving hard machining efficiency is a growing concern in industrial production, but environmentally friendly characteristics are guaranteed. Nanofluid minimum quantity lubrication (NF MQL) has emerged as a promising solution to improve cooling and lubrication performance in the cutting zone. This paper utilizes Box-Behnken experimental design to identify the influences of Al₂O₃/MoS₂ hybrid nanofluid MQL hard turning using CBN inserts on surface roughness and cutting forces. Mathematical models were employed to predict thrust cutting force, tangential cutting force, and surface roughness in hard turning under MQL conditions using Al₂O₃/MoS₂ hybrid nanofluid. The study results reveal that the minimum thrust force (F_y) occurs at a nanoparticle concentration of 0.5%, air pressure of 5 bar, and flow rate of 236 l/min. In comparison, the tangential force (F_z) reaches its minimum at a nanoparticle concentration of 0.8%, air pressure of 5 bar, and airflow rate of 227 l/min. The minimum surface roughness was achieved with a nanoparticle concentration of 1%, air pressure of 4.7 bars, and airflow rate of 186 l/min. Additionally, based on the multi-objective optimization, an optimal parameter set of NC=1%, p=5 bar, and Q = 210 l/min was identified to bring out the minimal values of surface roughness (R_a) of 0.218 &micro;m, thrust force (F_y) of 115.9 N, and tangential force (F_z) of 93.3 N.</span></span></span></div> MQL, surface roughness, hard turning, hybrid nanofluids, cutting force, lubricant, CBN 91 105 http://ijiepr.iust.ac.ir/browse.php?a_code=A-10-2726-2&slc_lang=en&sid=1 Tuan Ngo minhtuanngo@tnut.edu.vn 1800319475328460012433 1800319475328460012433 Yes Department of Fluids Mechanic, Faculty of Automotive and Power Machinery Engineering, Thai Nguyen University of Technology, Thai Nguyen 250000, Vietnam Bao Ngoc Tran baongoctran@tnut.edu.vn 1800319475328460012434 1800319475328460012434 No Department of Manufacturing Engineering, Faculty of Mechanical Engineering, Thai Nguyen University of Technology, Thai Nguyen 250000, Vietnam Minh Duc Tran minhduc@tnut.edu.vn 1800319475328460012435 1800319475328460012435 No Education Institute - Van Lang University, Vietnam. The Long Tran tranthelong@tnut.edu.vn 1800319475328460012436 1800319475328460012436 No Department of Manufacturing Engineering, Faculty of Mechanical Engineering, Thai Nguyen University of Technology, Thai Nguyen 250000, Vietnam. Trang Dang trang.dth@vlu.edu.vn 1800319475328460012437 1800319475328460012437 No Department of Manufacturing Engineering, Faculty of Mechanical Engineering, Thai Nguyen University of Technology, Thai Nguyen 250000, Vietnam.