Basic research concerning Electrical Discharge Machining with additive manufactured tool electrodes

在电火花成型加工的工艺链中，最高的制造工作量可以在工具电极的生产中找到。由于冲洗不充分，这种努力随着工具电极磨损的增加而增加。为了补偿工具电极磨损，需要更多的工具电极。选择性激光熔化（SLM）制造方法为EDM应用的加工工具电极提供了新的机会。具有内部冲洗通道的复杂形状的电极几何形状可以通过增材制造的制造原理来实现。硬质合金的材料特性非常适合在电火花加工中应用。由于加工碳化钨的高难度，迄今为止，碳化钨成形电极的制造一直被忽视。通过SLM加工碳化钨的可能性，这种材料除了在电火花钻孔操作中的应用外，还可以应用于电火花模具中的成形电极。本研究项目的目的是验证增材制造的碳化钨作为电火花加工的工具电极材料。SLM工艺参数的变化导致不同的钴含量GCo和改变增材制造工具电极的EDM工艺行为。应确定使用碳化钨工具电极粗加工不同材料的适当工艺参数。内部冲洗通道的实施导致加工结果的进一步改善，特别是当加工高纵横比A时。对实验结果的科学分析导致了EDM领域的广泛发现。所获得的知识和硬质合金WC-Co的特定材料特性允许改善重要的工艺特性，如EDM模具下沉中的材料去除率VW和电极磨损。该研究项目的结果可用于进一步的科学研究，例如通过进一步处理不同的涂层来改进SLM电极。增材制造的电极可以应用于精加工和抛光工艺。另一项研究可以分析向WC-Co中添加合金添加剂，例如碳化钒，以改善EDM工艺。

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.