Investigations on the effects of an innovative flank face modification for the drilling of nickel-base alloys

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

1)
Institut für Spanende Fertigung, Technische Universität Dortmund, Baroper Str. 303, 44227 Dortmund

a) buecker@isf.de; b) oezkaya@isf.de; c) biermann@isf.de

Kurzfassung

While nickel-base alloys provide high-temperature strength and outstanding mechanical durability, their machining is associated with high tool costs because of intensive tool wear which results in shortened tool lives. High temperatures occur at the cutting edges which are mainly induced in the tool itself, leading to thermomechanical overload of the cutting material. The developing tool wear also tends to have an influence on the surface integrity of the workpieces which involves microstructural transformations and white edging layers. In previous investigations, the occurring thermomechanical loads at the cutting edges of twist drills were analysed. The obtained data were used to simulate the stresses inside the drilling tools. Therefore, a tool design could be developed that provides important benefits while still being able to withstand the occurring loads. Subsequently, considering the gathered results, a flank face modification was ground into the tools’ flank faces. The tools were then tested in real life experiments.

The aim of the above-mentioned modification is a limitation of the wear zone at the cutting edge and the improvement of cutting fluid supply, especially at the cutting edge corners being subjected to the highest thermal stresses. During the experimental trials the wear progression of the tools as well as the occurring mechanical loads and the influences on the bore hole quality were analysed. The results show that a flank face modification of twist drills has the potential to notably extend the tool life of twist drills that are used to machine Inconel 718.

Schlüsselwörter

Inconel 718, Drilling, Flank face modification, 3D simulation, thermal simulation

Veröffentlichung

Procedia Manufacturing, 18 (2018), S. 20-26, doi: 10.1016/j.promfg.2018.11.003