Some parts simply cannot be machined using conventional methods: materials that are too hard, shapes that are too delicate, or cavities that are too deep or too fragile. In these situations,electrical discharge machining stands out as the go-to process.
This non-contact machining method pushes the boundaries of milling and turning, but its precision depends on one key factor: theelectrode. Its material determines the fineness of the details, the depth that can be achieved, and the tool’s service life.
The density, wear resistance, and electrical conductivity of tungsten and copper-tungsten make them the preferred electrode materials for these demanding applications.
A specialist in refractory metals, Concept Métal supplies and manufactures electrodes made of tungsten alloys used in electrical discharge machining.
What is electrical discharge machining, and how does it work?
Theelectro-erosion removes material through a series of electrical discharges created between an electrode and the workpiece, both immersed in a dielectric fluid. Each spark removes a tiny amount of material: there is no mechanical contact or cutting force. The only requirement is that the workpiece must be electrically conductive.
There are two main categories.
- Sdie-sinking electrical discharge machining uses a contoured electrode tool that reproduces its “recessed” profile in the workpiece.
- Wirewire EDM cuts through material using a taut wire that acts like an electric saw.
The choice of electrode material primarily depends on thepenetration where the shaped electrode is custom-made.
In what situations should EDM be the preferred method?
Theelectrical discharge machining is not always the first choice: it is slower than conventional machining. It is used when conventional machining reaches its limits. There are three main situations in which it is indispensable.
Hard and difficult-to-machine materials
Hardened steels, tungsten carbides, nickel-based superalloys, titanium: these materials are resistant to milling and cause rapid wear on cutting tools. Sinceelectrical discharge machining does not depend on hardness but on conductivity, it machines these materials with ease, regardless of their mechanical strength. This is a decisive advantage for high-performance tooling and parts.
Complex, fine, or deep geometries
Thedie-sinking allows for the creation of shapes that no rotary tool can achieve: sharp internal angles, narrow and deep ribs, blind cavities, and complex channels. Injection molds and die-cutting dies are typical examples, featuring details of a fineness and sharpness that are impossible to achieve otherwise.
Fragile parts with no mechanical stress
Because it operates without any cutting action, theelectrical discharge machining places no mechanical stress on the workpiece. It is therefore suitable for thin walls, fragile components, and areas that would deform under the pressure of a conventional tool. The resulting surface finish is also uniform and consistent.
Why are tungsten and copper-tungsten used for electrodes?
During penetration, the electrode also wears down with each discharge. Its material therefore determines both the precision of the result and how often it needs to be replaced. Compared to copper and graphite, copper-tungsten (W-Cu) and tungsten offer specific advantages.
Wear resistance and precision in detail
The tungsten has the highest melting point of any metal and excellent wear resistance. A copper-tungsten electrode therefore retains its sharp edges and geometry much longer than a copper or graphite electrode. As a result, fine details are faithfully reproduced, run after run, with reduced electrode wear. This is a major advantage for machining carbides and cavities with small ribs.
Density and Conductivity (W-Cu)
The copper-tungsten combines the best of both metals: the rigidity and thermal resistance of tungsten and the electrical conductivity of copper. This combination ensures stable and efficient material removal while withstanding high current densities. Dense and rigid, the electrode remains stable during discharge and guarantees better repeatability on deep and narrow shapes.
How to Choose an EDM Electrode?
The choice of electrode material depends on the desired balance between speed, finish, detail, and wear. Each material has its own area of expertise.
The graphite is suitable for large electrodes and rapid material removal. Copper provides a beautiful surface finish on simple shapes. copper-tungsten and tungsten are the go-to materials for challenging applications: fine details, deep grooves, sharp angles, machining of carbides and microelectrodes—where wear must be minimal and the geometry must be perfectly maintained.
In practice, tungsten or W-Cu is used when precision and reproducibility take precedence over raw speed. Concept Métal manufactures these custom electrodes in the grade and geometry suited to each application, based on your drawings.
Custom-made tungsten electrodes for electrical discharge machining
Theelectrical discharge machining is the solution whenever conventional machining fails: hard materials, complex geometries, fragile parts. In these cases, copper-tungsten and tungsten ensure precise details and controlled electrode wear—two key factors in cost-effectiveness for mass-production tooling.
Drawing on its expertise in tungsten and its alloys, Concept Métal advises you on the choice of grade and manufactures custom EDM electrodes for you. Contact our specialists for a quote tailored to your project.