Abstract

Drilling is one of the most important and common machining operations carried out in manufacturing industry. In drilling, the parameters such as hole-roundness, location and size, and interior surface finish are important for the proper functioning in the assembly. All of these parameters are related to the orbital motion of the drill during the drilling operation, which mainly arises from the lateral vibrations of the twist drill in a plane. In order to understand the dynamics of the process during drilling, a simplified two-dimensional model for the transverse motion of the drill rotating in a hole with clearance is employed. The model includes parameters such as the drill rotational speed, clearance between the drill and the hole, stiffness ratio of workpiece and drill, dry friction between the workpiece and the drill, and cutting force modulation factor. The effects of these parameters on the drill orbital motion and hole-quality of the workpiece are investigated.