Development and application of novel tool electrodes with external flushing channels to increase the economic efficiency of EDM drilling

• Applicant: Professor Dr.-Ing. Eckart Uhlmann
• Subject Area: Production Automation and Assembly Technology
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 431706863

The overall objective of this project is to provide novel tool electrodes for electro-discharge drilling (drilling electrodes) by identifying and introducing optimum geometries for external flushing channels to improve the flushing conditions in the working gap s during electro-discharge drilling with large drilling depths l, i.e. high aspect ratios φ.In various industrial applications, the need for precise drilling with high aspect ratios φ is growing. Examples include cooling holes in turbine blades, injection systems in the automotive industry, medical applications in dentistry and surgery, and sprue holes in mold construction. However, the production of deep, precise bore holes is often associated with problems such as increased relative wear ϑ, a limited material removal rate VW as well as the increasing flushing problem with an increasing aspect ratio φ and small working gaps s. The results of other authors on external flushing channels in rod electrodes provide contradictory findings. The basis for a process-safe design of electro-discharge drilling with high aspect ratios φ is a thorough and systematic investigation of the phenomena in the working gap s during the process. For the use of external flushing channels, no methodologically and holistically gained knowledge exists to date. In particular, the additional use of active flushing through the tool electrode promises further process improvements. This research project is dedicated to these objectives, i.e. a comprehensive experimental, numerical and metrological analysis of the processes in the working gap s when using drilling electrodes with optimized external geometry. After completion of the research project, fundamental knowledge about the fluid mechanical processes in the working gap s is available. These findings allow the deduction of process-improving flushing channel geometries for the provision and use of novel drilling electrodes as well as the approach to industrial application by providing manufacturing technologies and machining strategies for high aspect ratios φ. In this way, the widespread problem of limited aspect ratios φ and the associated uneconomical drilling at great drilling depths l can be countered.

• DFG Programme: Research Grants