Analysis of wire breakages in wire electrical discharge machining using electrical signal analysis and high-speed camera analysis

• Applicant: Professor Dr.-Ing. Thomas Bergs
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 555471381

For a robust increase in wire EDM productivity, detailed knowledge of the conditions leading to wire breakage is of the highest importance. In this regard, a visual inspection using high-speed camera technology in combination with a specific analysis of the electrical pulse characteristics as well as the current control-based axis position is an extremely promising approach for a significant gain in knowledge. Therefore, in the research hypothesis of this project proposal, the analysis of the physical wire breakage causes is addressed: By analyzing the spatially resolved discharge distribution on the wire by means of electrical process signals and camera-optical investigations, the physical causes of a wire breakage can be identified and transferred into a suitable description model. The attempt to verify / falsify this hypothesis is carried out in four work packages with experimental and simulative approaches. In WP1, the question must be answered first of all how a specific setup is to be designed in such a way that sufficient process observation can be carried out in-situ by means of a high-speed camera. In addition to an appropriate illumination of the gap, a suitable signal-based triggering is required to detect the wire breakage event and the position in the gap accurately. Subsequently, AP2 will investigate in experiments what influence different generator-related as well as process- and flushing-related parameters have on the probability of occurrence of a wire breakage. In parallel, WP3 provides for the preparation of numerical modeling approaches in order to be able to quantitatively describe the thermo-mechanical load spectrum affecting the tool electrode. The thermal and wear-related strength reduction of the wire electrode will also be taken into account. Finally, WP4 will answer the research question how to combine the empirical data with the model-based load estimates in a description model of wire breakages. Thus, the aim of the research project is the detailed empirical-numerical description of the processes and causes of wire breakage by superposition of experimental in-situ analysis data and numerical submodels for the influence estimation of acting process forces in an integrated model. The combination of transparent monocrystalline material, high-speed camera technology and the integration of the experimental setups into a modern industrial wire EDM machine promises a high degree of innovation and knowledge gain to increase the productivity potential in the industrial environment.

• DFG Programme: Research Grants