Productivity enhancement in wire electrical discharge machining through wire diameter and generator setting optimization (WEDM++)

• Applicant: Professor Dr.-Ing. Thomas Bergs
• Subject Area: Metal-Cutting and Abrasive Manufacturing Engineering
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 566464972

Electrical discharge machining (EDM) is an unconventional, non-contact, precision material removal process that is widely used to machine components that are typically of an intricate geometry, from electrically conducting materials that are often characterized by low conventional machinability. The process utilizes the heat generated from controlled, rapid electrical spark discharges and involves a tool and a workpiece that are separated by a gap that is filled with a dielectric fluid, across which the discharges are struck. Machining progresses under servo-controlled tool feed to repeatedly remove small volumes of material by the combined mechanisms of melting and vaporization. The process primarily involves Sinking EDM (SEDM) and Wire EDM (WEDM) configurations. Concerted research efforts have elevated WEDM performance already to impressive levels by largely focusing on electrode alloying and process control optimizations: removal rates, for instance, have increased by several folds in as many years. Such significant progress notwithstanding, WEDM continues to be limited largely by the low material removal rate relative to conventional machining. But major productivity advances require radical new optimization approaches. A better productivity can be realized simply by increasing the discharge energy or the duty factor. However, this approach causes a greater load on the wire, which significantly increases the risk of wire breakage. This would lead to a standstill in the process, so that exactly the opposite of the goal is achieved. The interrelationships and considerations described in the state of the art show the distinct potential of using thicker wire electrodes in combination with optimized generator settings which have been largely overlooked in the past.This protects the electrode from premature failure due to wear, so that the energy introduced into the system can be increased and enables faster processing. The objective of this research proposal is therefore to determine ideal wire electrode diameters and generator settings purely based on energetic considerations. This will be done both by a simulative and mathematical model approach to operate independent of the established wire diameter range. Experimental validation tests both on SEDM and WEDM machine tools will support and flank this. In particular, the influence of different electrode diameters on the process is being tested. This should result in correlations between diameters, dissipated energy and material removal. The different test setups allow the use of different generator technologies. First, the influences of process parameters on the cut kerf width and material removal are investigated so that models for determining the cutting speed can be created. The correlations found are validated by data from the experiments with wire electrodes run on a SEDM machine imitating WEDM with thicker diameters. An energy-related consideration can evaluate the resulting transferability.

• DFG Programme: Research Grants