Coconut Oil–Based Green Cutting Fluid for Sustainability of Machining Operations: Studies on Different Surface Roughnesses

Abstract Cutting fluids are crucial to machining, providing essential lubrication and thermal management during the process. Commercial Cutting Fluids (CCF) are generally based on mineral oils, with emulsifiers and additives that are produced chemically. Green Cutting Fluid (GCF), which is generally based on biodegradable plant-based oils, is an emerging alternative to CCF and is eco-friendly, non-toxic, and sustainable. In the present work, the viability of a coconut oil-based GCF has been evaluated to determine its suitability and effectiveness across a wide range of machining operations, by mimicking the surface roughness of various machining operations. For this, Ti–6Al–4V samples were prepared with unidirectional surface roughness in the 111- to 1350-nm range; the roughness range of various machining operations. The behavior of the GCF and CCF, including their Wettability, Interfacial Tension, Surface Energy, and tribological lubrication effectiveness, were studied and compared over these surfaces. The results show that the concentration of cutting fluid and surface roughness greatly influence the wettability and surface energy, respectively. GCF has shown competitive performance in comparison with CCF, showing its potential as a viable alternative to CCF . The article also includes a discussion on the sustainability and Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis of the GCF, and the work is in line with the United Nations Sustainable Development Goals (UN SDGs) 3, 11, 12, 13, and 15.