Green multi-biomimetic spontaneous oil-transport microstructure and its effects on energy consumption in sustainable intermittent cutting

The integration of vegetable oil and minimum quantity lubrication (MQL) can effectively improve the sustainability for machining process. Performance of vegetable oil MQL (VMQL) greatly influences energy consumption which is crucial to the level of sustainability. Three kinds of biological structure were referred to propose a novel green multi-biomimetic spontaneous oil-transport microstructure on tool surface for more sufficient lubrication. Morphology, contact angle and transport behavior were analyzed for the novel green microstructure. Novel models of specific cutting energy UAT and total energy ET were established considering tool wear evolution. This work investigated the influences of the proposed microstructure on the wear of the tool. Then, effects of the microstructure on UAT and ET were studied based on the novel energy models. Super lipophilic region RA and super oleophobic region RB existed on the microstructure. This study concentrated on the microstructure parameters such as depth Dg related to region RA and side length Lh related to region RB. It was found that efficient spontaneous oil-transport was achieved for both the entire microstructure and the microstructure element. The highest transport speed STA, the smallest tool wear rate WT, the lowest UAT and the lowest ET arose simultaneously at the parameter combination Dg = 22 μm and Lh = 120 μm. WT, UAT and ET were separately reduced by 37.14%, 43.50% and 33.52% at this parameter combination. Higher STA or lower WT caused lower UAT and lower ET. The green microstructure proposed in the work can be used for practical VMQL cutting to efficiently reduce energy consumption.