NATURAL OILS AS AN ECO-FRIENDLY LUBRICANT FOR MACHINING OPERATIONS, A REVIEW

Machining processes are the most common manufacturing operations for a wide range of products in our daily life produced from metallic, polymeric, and composite materials that undergo processing steps to be converted into final products. Turning operations for circular cross-section parts, drilling for cutting a rounded hole, and milling for cutting various configurations are the popular conventional machining processes for the manufacturing of different products. During the turning process, the work part is subjected to rotating speed as well as cutting force from the single point cutting tool which generates high friction forces between the pairs of contact surfaces – work part and tool-that lead to increases in temperature at the contact area. For drilling and milling operations, the cutting tools rotate at high cutting speeds and act by the cutting force on the work part, which also raises the heat at the contact area. Increases of generated heat at the cutting zone between the cutting tool and working material lead to several problems like wear of tool, tool failure, surface damage of machined parts, increased power consumption, and many hazardous effects to the operator by flying hot chips. To prevent or reduce the hazardous effect of heat on the working area, machining liquids are used for the purposes of cooling and lubricating of the contact zone. This comprehensive review concerned the importance of cutting fluids that are used during machining processes. It will focus light on natural lubricants; the pros and cons, economic and environmental impacts of using natural oils and lubricants as well as the challenges and prospects.