Experimental Investigations of Machinability in the Turning of Compacted Graphite Iron using Minimum Quantity Lubrication

Abstract

Unique mechanical properties of the compacted graphite iron (CGI) attracted attention of manufacturers and suppliers mainly in automotive industry in last decades. However due to the low machinability of the CGI material, more efficient machining strategies need to be implemented. Improvement in the cost-effective and environmentally sensitive processing of compacted graphite iron (CGI) is one of the major concerns of the manufacturing world because of the allure of CGI's mechanical properties. This study assesses the efficiency of minimum quantity lubrication (MQL) in CGI turning when compared to the dry-cutting condition. The turning tests were conducted across a wide range of cutting parameters: three different cutting speeds (100, 200, 300 m/min) and three different feed rates (0.1, 0.2, 0.3 mm/rev), all at a constant depth of cut (1 mm). The MQL efficiency is evaluated through cutting force and surface roughness measurements, optical and SEM analyses of chip formation and tool-wear analysis. The results showed that MQL usage provided a reduction in the resultant cutting forces by 2–5%, a reduction in surface roughness by 25%. The SEM analysis also revealed much clearer and smoother cutting edges on tool surfaces used in the MQL tests.