Grafting–inspired bionic hierarchical structure for efficiently enhancing cemented carbide tool performance in green turning

Constructing bionic hierarchical structure on tool surface is an effective method for enhancing tool performance in vegetable oil-based minimum quantity lubrication (VMQL) assisted turning. Taking the features of VMQL assisted turning into account, the bionic hierarchical structure is expected to possess high durability and superoleophobicity. In this way, the structure function can be efficiently maintained and the vegetable oil droplets can be fully utilized. This work explored a novel grafting–inspired bionic hierarchical structure (GBHS) on cemented carbide tool surface. The agriculture technique named grafting provided inspiration for fusing the bionic structures obtained by examining dung beetle and lotus leaf. Two kinds of GBHS, namely VDGS and VAGS, were acquired due to the changes of the diameter Dc of the bionic circular recessed microstructure and the laser processing angle Al. Morphology, wetting behavior, durable superoleophobicity, mechanism and green turning performance were analyzed for GBHS. It was verified that GBHS integrated the advantages of the bionic structures of different scales and weakened the shortcomings of them. VDGS and VAGS separately exhibited highly durable low-adhesive superoleophobicity and highly durable high-adhesive superoleophobicity when they were subjected to mechanical load and high temperature. The use of VAGS prepared at the laser angle Al of 60° caused the best machining results in short-time turning. VDGS with a diameter Dc of 360 µm can be employed to acquire the optimum machining results in long-time turning. The construction strategy of GBHS can be extended to other tool materials and green machining conditions for obtaining enhanced tool performance.