Comparative study of theoretical and experimental forces in micro drilling of aluminium 6061-T6

Abstract

Micro holes are needed in certain miniature components that find applications in aerospace, automobile and electronic industries. Micro drill used for producing such holes has two cutting elements, namely lip and chisel edge, participating in the material removal. Taking aluminium 6061-T6 as work material, the thrust and torque are predicted for micro-drilling of 0.5 mm size hole using a mechanistic approach. Appropriate cutting mechanics at different zones namely cutting lip, chisel edge and indentation zones are considered and individual as well as combined effects of edge radius and material strengthening on thrust force and torque have been brought out for the first time. It is shown that the major contributions of chisel edge towards thrust force and cutting lip towards torque are 70.3%-91.0% and 61.7%-63.4% respectively in the selected feed range. Predicted values of thrust force and torque are found to be in good agreement with experimental values obtained in peck drilling trials carried out on an ultra-precision KERN Evo machining centre.