EDM Machines: How they work

EDM Machines: How they work

how an EDM machine works

EDM is also called EDM (Electric Discharge Machining) and represents an important technology that is increasingly used in the mechanical industry today. (Discover all types of machining)

It is a technique that allows you to use the erosive capacity of the electric discharges to remove the excess material.

EDM drilling allows you to make holes with diameters from 0.3 to 6 mm on heights of over 300 mm, on any type of metal.


The electroerosion process use erosion effect of the metal that is obtained thanks to innumerable electric discharges that are generated between the electrode - piece to be worked and the electrode - tool.

The discharges form small holes on the surface of the workpiece and, continuing for a long time, form a regular sequence of holes.

In this way, the material is gradually removed from the surface of the piece.

Between the two electrodes – the tool and the workpiece – there is a very small cavity filled with a special dielectric liquid, the level of which is kept constant by means of an automatic regulation system.

The unconventional aspect of this machining lies in the fact that there is no contact between the tool and the piece during the removal of material, and it is possible to obtain complex three-dimensional figures with a high level of detail and surfaces with low roughness.


EDM represents one of the most interesting techniques in the field of precision machining, because it allows to obtain geometrically complex profiles with high precision that does not generate burrs and is not affected by the characteristics of the material being worked.

Compared to more traditional methods of removal, such as turning and milling, the method of removal by EDM has several advantages:

  • On the piece no mechanical effort is exerted;
  • IS guaranteed a good accuracy of the dimensions, regardless of the number of pieces to be executed;
  • IS possible to work any metallic material (regardless of hardness);
  • It's possible create any geometric or volumetric figure;
  • The electroerosion process has excellent machining tolerances (±µm);
  • Minimum intervention of the operator on the machine.

What is the difference between a sinking machine and a wire working one?

The machines for wire EDM and the machines for sinker EDM they are increasingly in demand and therefore it is important to clarify their use and their different characteristics.


Macchina Elettroerosione tuffo

EDM machining has theobjective of machining the piece so that it assumes a shape complementary to that of the electrode.

Machines for the electroerosive process are generally characterized by the presence of a tank in which the piece is positioned so that it is immersed in the dielectric medium during the entire process.

In plunge machining, the material used for the electrode-tools must be able to resist discharges, be easily workable in order to be able to reproduce any type of shape and, from an economic point of view, have low costs.

Experience has led to the use above all of three materials for making electrodes: graphite, copper and brass.

The typical applications of sinker EDM are linked to sectors in which it is necessary to work materials that are commonly difficult to carve and to work with traditional techniques, which due to their high mechanical, physical and thermal characteristics, they would be difficult to work with traditional techniques.

The sectors that use EDM are energy (turbogas and steam) and aeronautics. Some examples are the diffuser rings for the steam turbine, blades for turbines and the related cooling holes, or the realization of the surface finish for moulds for injection moulding.


elettroerosione a filo

By this process a taut conductor wire is used as an electrode for cut and profile the workpiece.

Some of the distinctive features of this technology, which make it preferable and highly sought after, are the ability to manage the processing of the finished part with great precision and to create even very complex pieces with a particular shape.
Furthermore, it is possible to perform machining with inclined cut and operate over 250mm thick.
The machining speed is lower than that of other chip removal technologies.

Wire EDM is mainly used in the making of moulds, in components for die makers, in mechanical parts for industrial molds and in components for the medical sector.

PCM Stampi it has, inside, several machines both flush and plunge, which are used for the machining of the various orders, capable of shaping even hard metal.


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