Performance evaluation of fruit tree-based vegetable pure oil and nanofluid MoS 2 as lubricant in minimum quantity lubrication during milling of AISI-304 stainless steel

Green machining technology has attracted considerable attention as an environmentally sustainable alternative to conventional cutting fluids. This study investigated the feasibility of tree-based vegetable oils, namely palm oil, virgin coconut oil, and olive oil, as base lubricants for minimum quantity lubrication (MQL), with and without molybdenum disulfide (MoS 2 ) nanoparticles, during the milling of AISI 304 stainless steel. Machining performance was evaluated in terms of cutting force, surface roughness, and chip morphology under dry cutting, pure vegetable oil-based MQL, and nanofluid MQL containing 0.3, 0.6, and 0.9 wt% MoS 2 nanoparticles. The results showed that vegetable oil-based MQL significantly improved machining performance compared with dry cutting. The greatest reduction in resultant cutting force was obtained using virgin coconut oil with 0.6 wt% MoS 2 at 150 m/min. This corresponded to a 41.72% reduction compared with dry cutting. Meanwhile, 0.3 wt% MoS 2 achieved a 37.16% reduction. The lowest surface roughness was obtained with palm oil containing 0.6 wt% MoS 2 , corresponding to a 44.0% reduction compared with dry machining; virgin coconut oil was 36.7%, and olive oil was 33.7%. Furthermore, virgin coconut oil-based nanofluid at 0.3–0.6 wt% MoS 2 produced the most favorable chip morphology, characterized by more homogeneous chip segmentation and smoother free surfaces, indicating improved lubrication at the tool–chip interface. Overall, these findings demonstrate that the investigated tree-based vegetable oils can contribute to improved machining performance during AISI 304 stainless steel milling under the specified conditions.