Minimum quantity lubrication advantages when applied to insert flank face in milling

This study compares tool life and surface roughness in milling of X100CrMoV5 mold steel for different lubrication conditions: dry machining, minimum quantity lubrication (MQL) through inner channels oriented to insert rake face, and MQL through inner channels oriented to insert flank face. It was proven that the tool life using MQL to flank face is increased by about 28.5% compared to dry cutting and about 11% compared with MQL to rake face. The improvement was proved to be a consequence of better lubrication on tool/chip and tool/workpiece interfaces. In fact, applying MQL to flank face generated longer and thinner chips compared to MQL applied to rake face and dry machining due to a lower friction effect. Additionally, SEM analysis revealed that MQL to insert flank face reduced the amount of adhesion materials compared to MQL on rake face and dry machining. Thus, this work shows that MQL applied through inner channels to insert flank face in milling can provide significant improvements in the cutting tool wear rate and/or productivity of cutting tool.