Wire eroding (EDM)
Do you need a few prototypes with complex cavities and undercuts of hardened steel? Electrical discharge machining (EDM) such as wire eroding, spark eroding and die sinking EDM offers special advantages for very complex workpieces.
Wire eroding is a cutting method that works according to the spark erosion principle. A CNC-programmed contour is cut by means of a metal wire (electrode) in an electrically conductive workpiece. Between the wire and the nearby workpiece, an arc is generated by means of a high-voltage pulse that melts the material structure, evaporates it and releases the molten metal from the microstructure. To keep the wire of brass, steal or tungsten from being consumed, it passes through de-ionized water (a dielectric). The surface roughness depends on the level of the selected voltage (high-voltage = greater removal and greater roughness). With wire eroding, the surface quality can be improved by means of several passes (rough cutting, finish machining, smooth finishing). Possible materials for wire eroding are copper, aluminum, normal steel, hardened steel, hard metal and special metals (all conductive materials).
Wire eroding is always economical in prototype construction when other types of cutting cannot be used. Very high-quality prototypes that are difficult to machine, are made of very hard or tough materials or contain complicated undercuts can be produced.
Advantages of wire eroding:
- Prototypes with complex shapes and contours
- A high level of dimensional accuracy, sharp-edge holes and pockets
- Also possible with very hard metals
- Extremely narrow cuts
- The good surface quality of Ra 0.5 can be improved by manual polishing
- Disadvantage: Long process cycles, large amount of energy
Wire eroding systems for:
- workpiece dimensions: Maximum 1700 x 1000 x 500 mm
- conical angle: up to 30°
To achieve a very high surface quality, repeated time-consuming cycles are required with spark erosion (additional cost):
- rough cutting Ra > 3 µm
- finish machining Ra 0.8 – 3 µm
- Smooth finishing Ra 0.5 – 0.8 µm