Effect of process parameters on drilling — An overview

Abstract

Out of all the machining operations, most commonly used operation is drilling. Drill forces, speed, feed, and temperature play significant roles in the drilling process because they are strongly related to drilling performance such as surface roughness and tool wear. The friction between the drill bit and workpiece will result in tool wear and chipping due to excess of drilling force. Sometimes, the difficulty of chip removal causes chip clogging and drill breakage, particularly with high strength metallic materials. Therefore it is necessary to identify optimal drilling conditions after a detailed study of the literature, in order to be process efficient as well as economical. A review of the effect of control factors and the mechanism of conventional and deep hole drilling process is carried out. Tool wear, friction, Built up Edge (BUE) and tool deflection are various threats depending upon the material being machined. In case of deep hole drilling, the effectiveness depends on torsional rigidity of tool, coolant supply and proper chip disposal. Further, specific application of deep hole drilling, such as in residual stress measurement, will require rigorous experimental and FEA evaluation. Finite element analysis of the drilling process is helpful to preview the stress state in the tool and work. This will help verify the selected cutting conditions.