Investigating the effects of vegetable oil-based cutting fluids with minimum quantity lubrication on machining performance of low-alloyed carbon steels: an optimization study

This work investigated the influence of Spindle Speed (N), Cutting Feed (CF), Depth of Cut (DC), Workpiece Type (WP) and Fluid Types (FT) on MQL-assisted turning of low-alloyed steels. Core interest in fluid types employed is the fatty acid unsaturation difference. Machining was conducted using Taguchi L27 design of experiment with N, CF, DC, WP and FT defined in the range of 435-870 rpm, 0.08-0.18 mm/rev, 0.3-0.7 mm, 84.00-109.00 HRB, and Rubber-Seed-Oil (RSO), Neem-Seeds-Oil (NSO) and Jatropha-Seeds-Oils (JSO) respectively. Response parameters measured are surface roughness, cutting temperature, chip thickness ratio and metal removal rate. Measured parameters were subjected to Analysis of Variance (ANOVA) at 5% significance, Taguchi analyses and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS). Results obtained showed WP was statistically significant with 48.77% contribution on surface roughness while difference in fluid types unsaturated fatty acid compositions has no significant effect on surface roughness. However, JSO having linoleic acid, thermal resistivity and viscosity values 27.87-34.87%, 664.40 +/- 14.35 and 140.0 cP respectively, gave optimum value of surface roughness. All factors except N had significant effect on chip thickness ratio with WP having the most dominant with 50.91% contribution and RSO with lowest viscosity value of 125.5 cP gave rise to optimum chip thickness ratio due to the most efficient flowability occasioned by high linoleic acid (34.70-37.45%) present. N and CF were the only statistically significant factors on metal removal rate. TOPSIS proved that 870 rpm, 0.18 mm/rev, 0.5 mm, RSO and LAMCS-109 HRB optimized the MQL-assisted turning.