Investigations into surface integrity and cylindricity error during peck drilling of aerospace alloy using graphite, MOS2 and blasocut lubricant

Abstract

Abstract Surface integrity of drilled hole plays a vital role in automobile, biomedical and aircraft industries. However, drilling of aluminium is always a challenging task in manufacturing industry. This is due to high chemical affinity nature of aluminium alloy causes build edge formation on the tool which increases an energy consumption and led to poor surface integrity as reported in literature. In view of this, an attempt has been made to focus on improving the surface integrity and hole geometry using blasocut, graphite and molybdenum disulphide lubricant and compared with dry conditions. A detailed experiment has been carried out at various spindle speeds of 400, 1200, 2000, 2300 rpm and feed rate of 50, 75, 100, 125 rev/sec. The effect of drilling parameters, blasocut and solid lubricant coating on surface finish, micro hardness and cylindricity error has been analyzed in depth. There is a substantial improvement in surface roughness, micro hardness for solid lubricant assisted peck drilling. Cylindricity error is high in dry and blasocut condition whereas graphite and molybdenum disulphide lubricant results in better hole geometry and thereby there is a reduction in cylindricity error. A better surface finish of 150 nm is observed in the hole geometry surface by using molybdenum disulphide coated drill tool for the combination of 2300 rpm cutting speed and feed rate of 50 rev/sec.