Scientists and tribologists are currently exploring sustainable and inexhaustible lubricants as a result of increased awareness of environmental and health-related issues. Vegetable oils are being investigated as a potential form of environmentally friendly cutting fluids due to their excellent renewability, biodegradability, and lubricating performance. This report provides an overview of different vegetable oils used as cutting fluids in the machining of engineering materials. The effects of virgin vegetable oils, emulsified vegetable-based oils, and vegetable-oil-based nano-cutting fluids on the cutting force, the surface finish of machined parts, the tool wear, and the temperature of the cutting area were surveyed critically. Compared to mineral-oil-based cutting fluids, studies have demonstrated that vegetable-oil-based cutting fluids meet cleaner manufacturing standards with good or better efficiency.

In this study, palm kernel oil, an eco-friendly oil, was extracted from its seeds and then examined for thermal and physiochemical characterization. Subsequently, the performance of palm kernel oil was evaluated in comparison with standard mineral oil during the milling of AISI 1018 steel with a double milling tool using the MQL technique. The influence of cutting conditions such as feed rate, spindle speed, and DOC on response variables (cutting temperature and surface roughness) was studied using a Taguchi L₉ orthogonal array. Using the TOPSIS approach (a compensatory method that provides a more realistic form of modeling than non-compensatory methods, and allows trade-offs between criteria, where a poor result in one criterion can be voided by a good result in another criterion) an integrated structure for modeling and optimizing the process was developed. The findings showed that palm kernel oil had a 54% oil yield. In terms of machining, palm kernel oil performed much better than mineral oil lubricants. From the results obtained, palm kernel oil reduced the surface roughness by about 15.6% over mineral oil. Effective cooling in palm kernel oil led to reduced cutting zone temperatures, which in turn extended tool life and improved cutting stability. Additionally, ANOVA was used to show the parameters' significant influence on the output responses. The findings showed that feed rate and depth of cut had the greatest impact on the responses for palm kernel oil and mineral oil, respectively.

The hunt for environmentally friendly cutting fluids is underway as the problems of conventional cutting fluids become more evident. To achieve environmentally conscious machining, the current study examines the use of Mango Kernel Seed Oil (MKSO) as a cutting fluid during the turning of AISI 1525 steel. According to the 2⁴ complete factorial techniques, the vegetable-oil-based cutting was produced by dissolving four different additives in mango kernel seed oil: emulsifying, antimicrobial, anti-corrosive, and antifoam substances. Afterward, the formulated vegetable oil was characterized both physically and chemically to determine its capability. The developed MKSO was mechanically evaluated using a Taguchi L₉ orthogonal array. Spindle speed, depth of cut, and feed rate served as the input parameters, while surface roughness, cutting temperature, machine sound level, and machine vibration rate were the responses. Taguchi-based Grey Relational Analysis was used to perform multi-objective optimization. It was used to determine the best machining conditions. The best parameters for mango kernel seed oil are a spindle speed of 0.683 rev/min, feed of 0.617 mm/rev, and depth of cut of 0.620 mm, while the optimum parameter for Mineral-Oil-based Cutting Fluid (MOCF) is 0.7898 rev/min spindle speed, 0.6483 mm/rev feed, and a 0.6373 mm depth of cut. This research revealed that, when compared to the feed rate and the depth of cut, the spindle speed has the highest influence on multi-responses in turning operations with both cutting fluids. Generally, MOCF outperformed mango kernel seed cutting fluid in most machining conditions.

Cutting fluids are used for cooling and lubricating the machining area of components used in manufacturing industries such as aerospace, automotive, petroleum, and heavy machinery. Mineral oils derived from petroleum are commonly utilized as cutting fluids. Mineral oil is hazardous to the health of workers and damaging to the environment. There is a need for a substitute for mineral oil. Vegetable oil is increasingly being used as a cutting fluid. Vegetable oils are easily accessible and have benefits including excellent biodegradability, resistance to fire, low humidity rates, and a low coefficient of expansion under heat. This study adopts watermelon oil as a lubricant in MQL machining of AISI 1525 steel using tungsten tools. In the experiment, the feed rate, depth of cut (DC) and spindle speed were varied using the Taguchi L₉ orthogonal array. Grey relational analysis was conducted to obtain optimum cutting parameters for surface roughness, machine vibration, and cutting temperature. Hardness and microstructural analysis of the workpiece were also conducted. Results showed that vegetable oil performed much more effectively than mineral oil in most experiments. The DC was shown to be the most efficient cutting parameter after applying ANOVA analysis based on the parameters that were evaluated. Additionally, models for cutting temperature, machine vibration, and surface roughness values have been developed with accuracy between 69.73 % and 99.05 %. The hardness of the workpiece increases with an increase in diameter, which was attributed to the increase in the steel rod (workpiece) cross-sectional area and the likelihood of a more uniform stress distribution. Moreover, finer grain sizes were observed at 70 mm diameter, with the predominant presence of pearlites. These characteristics were reportedly beneficial to the material's toughness and strength.

Aluminium-based materials are lightweight materials used for producing automotive and aircraft components. However, aluminium materials diminish in performance on exposure to degrading environments, which limits their areas of usage and applications. The degrading effect results in poor resistance to wear and corrosion, reduced properties and defective microstructure. In this work, 6063 aluminium alloy was reinforced with particles of agricultural waste (walnut shell) to produce six samples with five samples of reinforced and a control (unreinforced) sample. Each of the samples of the reinforced alloy was moulded into a 25 mm diameter by 130 mm height using the stir casting method using an industrial pit furnace. The samples were thereafter machined to a diameter of 20 mm and cut into a thickness of 10 mm for characterizations. The potentiodynamic polarization method was used to test for the samples’ corrosion resistance properties following the ASTM G102 standard in a 3.65% NaCl test medium. The hardness property was investigated using the Brinell hardness machine following the ASTM A-370 standard, while the microstructure and crystallographic phase studies were carried out using SEM/EDS and XRD profiles, respectively. The unreinforced 6063 Al alloy sample exhibited the highest corrosion rate (Cr) of 0.7321 mm/year and the lowest hardness of 104.94 kgf/mm². The 10% wt. walnut shell particles (WSP) reinforced 6063 Al alloy sample exhibited the lowest corrosion rate (Cr) of 0.1336 mm/year and the highest hardness of 109.24 kgf/mm². This indicated that the walnut shell particles enhanced the corrosion and indentation resistance of the alloy. In addition, the SEM images indicated that the agricultural waste (walnut shell particles) reinforced samples exhibited more refined microstructure, lower porosity and smoother morphology compared to the unreinforced (control) sample. Also, the XRD profile of samples revealed some high peak intensity crystallites such as Al(ZnS), Al₂O₃ and (FeMn)SiO₂. These high peak intensity crystallites indicated that these reinforced samples possessed chemical and microstructural homogeneity, high stability and good surface texture.