Optimizing Cutting Parameters for Effective Turning of EN-31 Steel by Utilizing Vegetable-Based Cutting Fluids as a Coolant

<div>The primary objective of this article is to study the improvement of machining efficiency of EN-31 steel by optimizing turning parameters using newly developed cutting fluids with different proportions of aloe vera gel and coconut oil, utilizing the Taguchi technique. Furthermore, performance metrics including material removal rate (MRR), surface roughness, and tool wear rate (TWR) were assessed. Analysis of variance (ANOVA) suggested that as cutting speed and feed increase, the MRR is positively influenced, but likewise tool wear is intensified. The surface roughness exhibited a positive correlation with cutting speed, and a negative correlation with increasing both cutting speed and feed. It was found that the maximum MRR value was attained at a cutting speed of 275 m/min, a feed rate of 1.00 mm/rev, and a cutting fluid composition of 30% aloe vera and 70% coconut oil. For the best surface smoothness, it is advisable to adjust the cutting speed to 350 m/min and the feed rate to 0.075 mm/rev. A cutting speed of 275 m/min and a feed rate of 1.00 mm/rev led to a lower TWR. The results suggest that the combined use of coconut oil and aloe vera as cutting fluids improves the turning quality of EN-31 steel, particularly when employing a combination of 30% aloe vera and 70% coconut oil. As a possible solution for performance problems in achieving desired results during the turning of EN-31 steels, these recommendations may be used in industries to enhance turning performance.</div>