The Influence of graphite, MOS2 and Blasocut lubricant on hole and chip geometry during peck drilling of aerospace alloy

Abstract

Aluminium alloy is predominantly using in aerospace and automobile structure applications due to high strength to weight ratio. In general aluminium alloys are easy to machine due to high stacking fault energy. However chip adhesion and built edge formation on the cutting tool are the major issues reported in literature. To overcome this, a novel attempt has been made by employing peck drilling in dry, blasocut, graphite and molybdenum disulphide [MoS 2 ] condition. A detailed experiment has been conducted by varying drilling process parameters. All the experiments are carried out three times and average values are taken for hole accuracy, circularity error, chip morphology, entry and exit burr on hole. It is inferred that accuracy of the holes are improved in solid lubricant assisted machining over blasocut lubricant and dry machining. Circularity error is observed minimum in graphite and MoS 2 assisted machining. Burr formation is observed in the hole exit for dry peck drilling of aluminium alloy, whereas in graphite and MoS 2 assisted machining there is no burr formation in both entry and exit side of the hole. Long continuous, cone shaped chip morphology with smooth surface during peck drilling is the evidence for improvement of hole accuracy in graphite and MoS 2 assisted drilling