ECDM process

The ECDM method ( E lectro C hemical D ischarge M achining) is a combination of the two known manufacturing process, the electrical discharge machining (EDM) and electro chemical ablation (ECM). The ECDM process, also referred to as a "hybrid" manufacturing process, combines the technical advantages of EDM and ECM and is used today for the production of small bores in injection technology in the automotive industry.

With the ECDM method, electrically conductive materials can be processed by means of electrical discharges that are generated in an electrolyte solution , for example from a mixture between demineralized water and a powdered chemical salt.

The physical principle of the process can be described as follows: After applying an electrical voltage between a tool (cathode) and a workpiece ( anode ), which are separated from each other by a certain distance ( working gap ) of a few micrometers, first in the electrolyte solution, which is located between the tool and the workpiece, the formation of gas ( hydrogen ) at the cathode and an electrochemical removal of the workpiece material, d. This means that the so-called ECM phase of the ECDM process is developed here. As the process progresses, the gas volume, which also moves towards the opposite workpiece, increases at the cathode, so that the electrical resistance of the working gap is gradually increased. The gas volume then reaches the surface of the workpiece and thereby causes the complete electrical insulation of the working gap. An electrical discharge occurs, which causes the workpiece and tool material to melt. The phenomenon of electrical discharge is said to be the beginning of the EDM phase of the ECDM process.

Web links

• Brief overview of an application of the ECDM process for dressing grinding wheels, on iwf.mavt.ethz.ch (PDF) (638 kB)
• AV Kulkarni; MG Karnik Experimental Measurements and Theoretical Estimation of Temperature in ECDM Process , on ieee.org (PDF file)
• John Webster Recent Research on Externally-assisted Grinding Processes (dt .: Studies on externally supported grinding processes ) (Engl.) On www.abrasivesmagazine.com (PDF) (120 kB)

literature

• M. Schöpf: Electro Chemical Discharge Machining (ECDM): New possibilities for dressing metal-bonded diamond grinding wheels. Diss. ETH Zurich, 2001
• Fritz Klocke , Wilfried König : Manufacturing process 2: grinding, honing, lapping. Springer, 2005, ISBN 3540234969 ( online )