Influence of Threshold Based Process Control on Sinking EDM of a High Aspect Ratio Geometry in a Gamma Titanium Aluminide

The demand for higher efficiency in aircraft propulsion engines leads to materials with increasing thermomechanical strengths. The intermetallic gamma titanium aluminides (γ-TiAl) are attributed a great potential in this field, but the machinability of γ-TiAl by conventional processes is challenging. One alternative manufacturing technology for these materials, especially for cavities with a high aspect ratio such as seal slots in turbine blades, is sinking EDM. Since the process stability in terms of a constant feed rate is not guaranteed for high plunging depths, this paper focuses on an experimental approach to investigate interdependencies between common process control strategies and process output parameters (e.g. feed rate, surface integrity) during the machining of cavities with high aspect ratios in the intermetallic alloy TNM-B1.