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2023
Conference Paper
Titel
Surface modification of tungsten carbide cobalt tool electrodes by heat treatment under nitrogen atmosphere for electro-discharge drilling
Abstract
The requirements for high-precision components for tool and mould-making, automotive and aerospace industries are constantly increasing. Due to the strong mechanical properties of the used materials, such as tool steels and nickel-based alloys, conventional cutting processes are not always suitable. Instead, electrical discharge machining is used for cutting electrically conductive materials. One challenge even today is debris formation, causing arcs and short-circuits in the lateral working gap. This applies particularly to electro-discharge drilling with high aspect ratios and increased difficulties of debris removal. This leads to increased process instability, tool wear and conicity as well as decreased material removal rates. To reduce the effects of arcing and short-circuits in the lateral working gap, tungsten carbide-cobalt tool electrodes with an outer diameter of dO = 1.5 mm were heat-treated to increase the electrical resistivity of the electrode's surface. For this purpose, two different ambient atmospheres were selected, a nitrogen atmosphere and vacuum in comparison. Subsequently, the modified tool electrodes were used to produce boreholes in tool steel of the type Elmax Superclean with a depth of et = 6.75 mm by electrodischarge drilling. The surface modification in the nitrogen atmosphere led to a slightly higher material removal rate and a decrease in the linear tool wear of the tool electrode by up to 6.67 % compared to an untreated reference electrode.
Author(s)