Spark erosion machine
The EDM machine requires a tool ( electrode ) made of a material with high electrical conductivity such as copper , graphite or tungsten , as well as a dielectric that fills the space between the tool and the workpiece . During machining, an electrical voltage is applied between the workpiece to be machined and the electrode that is clamped in the machine. The electrode is a negative form of the mold that is to be introduced into the workpiece to be machined.
During machining, a pulsating direct current creates an arc between the electrode and the workpiece. Components are removed from the workpiece by evaporation or by flaking. The removed or evaporated components are transported through the dielectric - a non-conductive liquid, e.g. B. a special oil - washed away.
The problem with the method is the low volume removed and the high production costs of the electrode, which can sometimes make up more than 50% of the total costs.
Spark erosion machines are mainly used in tool making . They are used to process all metals and metal alloys, such as B. steel (also hardened), aluminum , copper, brass and exotic species such as molybdenum and zirconium are used. Other conductive materials such as graphite and some types of ceramics can also be machined very well by erosion. In the field of die-sinking EDM is often by HSC - milling machines (for hard and hardened metals) and added 5-axis milling machines or partially replaced.
Spark erosion machines are available in two versions that offer different processing options:
- Wire EDM (spark erosion cutting)
- Die-sinking eroding whereby there are different versions (e.g. drill eroding ), which differ mainly in the number and type of their axes (X, Y, Z, C ...) (spark-erosive sinking)