Ultra-Fine Bubbles (UFB) Inserted Novel Coconut Oil Based Metal Working Fluid (MWF) As a Sustainable Lubricant for Turning of Ti-6Al-4V

As for the first time in the advanced manufacturing research and development sector, the nano range bubbles (i.e., UFB) were injected to the coconut oil-based metal working fluid (COCO) to facilitate better cooling and lubrication condition for machining difficult to cut materials. Higher heat transfer characteristics, and better purification properties of the UFB were incorporated to the higher free fatty acid contained COCO to facilitate a favorable machining condition. Moreover, COCO ensures health and environmental friendliness and express higher potential to replace the toxic and hazardous synthetic oil based MWF (SynO) from the machining process. In this study, the cooling and lubrication performance of the UFB inserted novel COCO was clarified and benchmarked with a commercially available high performance SynO for machining Ti-6Al-4V. Eighteen percent cutting force reduction was obtained due to the hybrid effect of UFB and free fatty acid. Additionally, lower work tool interface temperature, surface roughness, and tool wear were obtained at the UFB inserted COCO compared to the SynO. Hence, the excellent tribological and rheological properties of the UFB inserted novel COCO has concluded high performance sustainable machining and provided a promising solution to conquer the challenges (i.e., low machinability index and sustainability) of machining Ti-6Al-4V.