Basic research concerning Electrical Discharge Machining with additive manufactured tool electrodes

• Applicant: Professor Dr.-Ing. Eckart Uhlmann
• Subject Area: Production Automation and Assembly Technology
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 451468634

In process chains with EDM die-sinking the highest manufacturing efforts can be found in the production of tool electrodes. This effort multiplies with increasing tool electrode wear ϑ because of insufficient flushing. A higher amount of tool electrodes is required in order to compensate the tool electrode wear. The manufacturing method Selective Laser Melting (SLM) offers new opportunities in machining tool electrodes for EDM applications. Complex form electrode geometries with interior flushing channels can be realised with the manufacturing principles of additive manufacturing. The material properties of tungsten carbide are ideal for the application in EDM. Due to the high effort in machining tungsten carbide, the manufacturing of form electrodes out of tungsten carbide has been neglected so far. By the possibility to machine tungsten carbide by SLM, this material can be applied for form electrodes in EDM die-sinking besides the application in EDM drilling operations.The aim of this research project is the validation of additive manufactured tungsten carbide as tool electrode material for EDM. The variation of the SLM process parameters leads to differing cobalt content GCo and changing EDM process behaviour of the additive manufactured tool electrodes.Appropriate process parameters for rough machining of different materials with tungsten carbide tool electrodes shall be identified. The implementation of interior flushing channels causes further improvement of the processing results, especially when machining high aspect ratios A. The scientific analysis of the experimental results leads to extensive findings in the area of EDM. The acquired knowledge and the specific material characteristics of the carbide WC-Co allow the improvement of important process characteristics like material removal rate VW and electrode wear in EDM die-sinking. The results of this research project can be used for further scientific investigations like improving the SLM electrodes by further processing with different coatings. The additive manufactured electrodes could be applied for finishing and polishing processes. Another investigation can analyse the addition of alloying additives to WC-Co, such as vanadium carbide in order to improve the EDM process.

• DFG Programme: Research Grants