Haalbaarheid van een hybride draadvonk-elektrochemisch bewerkingsplatform

This thesis presents an investigation into the hybridization of wire electrical discharge machining (wire EDM) and wire electrochemical machining (wire ECM) processes, aiming to enhance precision and surface integrity in wire EDM applications. Wire EDM, a widely used non-conventional machining technique, is often challenged by surface damage due to its thermal removal mechanism, limiting its application in high-precision industries or requiring extensive postprocessing. To address these issues, this research explores a hybrid wire EDM/ECM approach that combines the strengths of both processes, leveraging EDM's accuracy and shaping efficiency, and ECM's capability of non-damaging material removal. The research begins with a comprehensive analysis of the fundamental principles of EDM and ECM and their derived hybrid techniques. Next, the lesser-known wire ECM process is explored by modelling the current density, and the effects of several parameters, such as the interelectrode gap and pulse frequency. The wire EDM and wire ECM processes are studied in a hybrid electrolyte medium, acting as a non-ideal dielectric during wire EDM, and as a low conductive electrolyte during wire ECM. As wire EDM is usually performed in deionized water, its behaviour in electrolyte is not well studied. Wire ECM is similarly explored with respect to the influence of the parameters on the roughness and removal depth. After the investigation of the fundamental processes, the hybrid wire EDM/ECM platform is explored, and the resulting surfaces are studied. These surfaces often contained pits, which are caused not only by material removal at low current densities, but also due to defects already present in the material such as sulphide inclusions in the hot-rolled stainless steel bar stock. Next, the geometric accuracy is investigated and resulted in impressive results with a deviation of approx. 5 µm, which is within the tight tolerance ranges of the target aerospace applications. Besides using the hybrid platform for material removal, it can be used as a tool for metrology by measuring the resistance of the interelectrode gap. The distance between the tool and the workpiece can be estimated and correlates well to the modelled resistance. This thesis demonstrates the potential of hybrid wire EDM/ECM for industrial applications, such as in aerospace components and complex moulds, where high accuracy, durability, and surface quality are critical. The work concludes with recommendations for future research, focused on optimizing production efficiency and expanding the hybrid process's applicability to a broader range of materials and geometries.