Comparative analysis of sustainable cooling systems in intermittent turning of magnesium pieces

Abstract

Cutting fluids have been widely used in machining processes because of their favourable lubrication and cooling properties. However, their high costs, the risk to worker’s health and environmental concerns have necessitated the development of alternative methods of cooling and lubricating that eliminate or, reduce such drawbacks. In this study, a comparative analysis of two sustainable cooling systems (dry machining and minimum quantity lubrication (MQL) system) in intermittent turning of UNS M11917 magnesium pieces was performed. To analyse the influence of the cooling system on intermittent cutting, the surface roughness was selected as the response variable. In addition to the cooling system, other parameters such as the feed rate, spindle speed, tool type, interruption type and measurement zone (defined by the length and the generatrix) were taken into account. A combined L4 x32 experimental design with three nested replications was carried out. The obtained data were analysed using the analysis of variance (ANOVA) method. Main conclusions include the identification of the feed rate and interruption type as the most important sources of surface roughness variability. In addition, it is possible to affirm that, in general, increases in the coolant flow rate, within the range studied, lead to slightly poorer surface roughness results.