Evaluation of lubri-cooling effects on the total milling performance of SiCp/Al 65 vol% composite

SiCp/Al metal matrix composites with high SiC content are difficult to machine due to increased cutting resistance, tool loading, and poor surface quality. This study evaluates the milling performance and sustainability of SiCp/Al 65 vol% composite for dry cutting, minimum quantity lubrication (MQL) and CO₂ snow cooling. The impacts of cooling conditions, cutting speeds and feed per tooth were evaluated with respect to cutting force, surface roughness, cutting power, energy consumption, carbon emission and sustainability indicators in general. The results show that MQL offers the best balance of total milling performance (TMP). The average tangential cutting force was decreased by 18.7% as a result of MQL and 12.9% as a result of CO₂ snow compared to dry cutting. The surface roughness for MQL and CO₂ snow were reduced by 23.3% and 7.3%, respectively, compared with dry cutting, and same trend followed by carbon emissions. Total cutting energy decreased with increasing feed per tooth, as power increased with the shorter time the cutting was made. Compared with dry cutting, MQL and CO₂ snow reduced the average cutting energy by 21.9% and 12.9%, respectively. The same trend was seen in carbon emissions, where the lowest average value was for MQL. However, at the maximum feed per tooth, CO₂ snow provided 6.1% lower cutting energy and associated carbon emissions than MQL. In general, the use of MQL can be recommended for balanced sustainability performance, and CO₂ snow for high feed and residue-free machining. These findings provide practical guidance for selecting suitable cooling/lubrication strategies for efficient and sustainable industrial milling of high-volume-fraction SiCp/Al composites.