Electro-discharge ultra-fine drilling with carbon fiber electrodes

• Applicant: Professor Dr.-Ing. Eckart Uhlmann
• Subject Area: Joining and Separation Technology
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 429769676

The current processing limits of electrical discharge ultra-fine drilling are at minimal bore diameter Dmin < 3 µm with aspect ratios 0.5 < l/D < 7.5. Challenges in electrical discharge drilling with small diameters D lie in the manufacturing and guidance of the tool electrode. For bore diameters D ≤ 50 µm, conventional rod electrodes cannot be used. Instead, the required rod electrodes must be produced through electrical discharge dressing, leading to a significant increase in manufacturing effort and costs. The small diameters de, good electrical conductivity κ, and low production costs are the main advantages of carbon fibers compared to conventional electrodes for the production of bore diameters D in the micrometer range. In the scope of the investigations in the first funding period, it was successfully demonstrated that electrical discharge drilling with carbon fiber electrodes is fundamentally feasible. The aim of the current research project, in the second funding period, is to gain knowledge into manufacturing technologies and machining strategies for electrical discharge ultra-fine drilling with adaptive energy adjustment using carbon fiber electrodes. The focus is on obtaining fundamental knowledge into the feasibility of the generator technology for achieving discharges with adaptive discharge energy for the use of carbon fiber electrodes, as well as providing an effective flushing strategy during the process. The objective is to increase process stability in electrical discharge micro-drilling with carbon fibers, thereby improving manufacturing results in terms of shape accuracy GF and quality. Furthermore, fundamental knowledge of the use of adaptive discharge energies We for the application of ultra-thin tool electrodes in electrical discharge machining are obtained. Upon successful completion of the second funding period, knowledge and technologies that allow the efficient and economical use of electrical discharge ultra-fine drilling with carbon fiber electrodes will have been acquired. By the end of the entire research project, comprehensive fundamental knowledge about electrical discharge ultra-fine drilling with carbon fiber electrodes, adaptive energy We adjustment, and effective flushing strategies will be developed, thus making a significant contribution to the advancement of the state of the art. The results of the research project will provide scientific foundational knowledge as well as industrially applicable technologies that give Germany a competitive advantage in the global competition in both science and economy. Especially in areas such as aerospace technology, automotive technology, and textile and consumer goods industries, the results of this research project could be implemented.

• DFG Programme: Research Grants