Simulative analyses focused on the changes in cutting fluid supply of twist drills with a modified flank face geometry

Özkaya, E.1, a; Bücker, M.1, b; Biermann, D.1, c

1)
Institute of Machining Technology, TU Dortmund University, Baroper Str. 303, D-44227 Dortmund, Germany

a) ekrem.oezkaya@tu-dortmund.de; b) milan.buecker@tu-dortmund.de; c) dirk.biermann@tu-dortmund.de

Abstract

In this paper, a combination of Finite Element Method (FEM) and Computational Fluid Dynamics (CFD) simulations is presented. They were performed in order to develop an optimised flank face design for twist drills used for machining Inconel 718. This modification consists of a retraction behind the cutting edge which is ground into the tool flank face. It results in an increased free volume behind the cutting edge which can then be filled with cutting fluid, but in consequence, there also is a decrease in cutting material stabilising the cutting edge. Therefore, sufficient mechanical strength of the remaining cutting edge had to be ensured. At the same time, the increase in cutting fluid flow behind the cutting edge also helps to protect the remaining cutting material from the high temperatures which occur when machining nickel-based alloys such as Inconel 718. After the simulation-based findings had been transferred to real tools modified by grinding, subsequent experimental investigations could show that twist drills with a modified flank face reached tool life up to five times longer compared to standard tools.

Keywords

CFD, FEM, Inconel 718, Drilling, Tool development, Flank face modification

Publication

International Journal of Mechanical Sciences, 180 (2020), doi: 10.1016/j.ijmecsci.2020.105650