Study of the local forces along a cutting edge when drilling Ti6Al4V - comparison of methods

Abstract

In aerospace applications, drilling is one of the most common operations. However, this machining stays complex and expensive, especially for difficult-to-cut materials such as titanium alloys. Because drilling is a blind operation, the physical measurements in-situ or the observation of phenomena close to the cutting edge is hard to observe. This study focuses on two different methods allowing the evaluation of the local forces along the main cutting edge. The first method is based on a physical decomposition of the drill edge. The global forces are measured when drilling samples with various external diameters: 1) smaller or larger than the drill diameter; 2) with or without pilot hole. The forces measurement for each sample lead to the determination of the elementary forces along the cutting edge and the margin. The second method decomposes the forces during the progressive drill point entry in the work material. On each Z level, the drill edge engagement is geometrically determined, allowing the knowledge of the elementary forces applied along the cutting edge and the margin.