In the first half of the twentieth century, scientists have proposed a metal processing via spark charge.This technique is called electro-discharge machining.The principle of operation is simple and handling is as follows: in a liquid dielectric is made by the convergence of two voltage electrodes (anode and cathode).Moreover, the role of the cathode performs workpiece.Between the anode and cathode an electric discharge.During the interaction energy is released that can warm up and remove the metal particles from the surface of the electrode.In other words, the metal layers are destroyed under the effect of electric discharges (metal erosion).
Through applying a voltage to the electrodes in the form of short pulses of energy into the metal is not affected.This ensures that during processing the item will not lose their physical properties.
Electrical discharge machining.The principle of
In practice, EDM is as follows:
- Procurement (cathode) is set on the table.
- Preparation tools for machining (wire part made of copper, graphite, brass, aluminum) with a pre-treated surface.The surface must form repeating the plane to be obtained on the workpiece.
- Tool holder in the moving parts of the machine.It applied to the instrument impulse voltage.Next, the tool approaches the workpiece.
- emergence of "breakdown" of the dielectric in the form of a spark between the surface of the workpiece and the tool.
- sparks in the contact zone with the workpiece surface takes place the ejection of the metal microparticles.Form small funnel.Its depth is equal to the voltage between the workpiece and the tool.
note is the fact that the spark jumps between very close to each other surface portions of the tool and the workpiece.Grain by grain, millions of small sparks remove damaged metal with the machined surface.Iskorki more approximate the surface shape to the surface of the tool in the inverted form.In the process, you can maximize the purity and uniformity of processing by changing the voltage variation on the instrument, and a spark gap.If the wire is to use the tool, the workpiece is cut with greater accuracy.Furthermore, it is possible to achieve an increased circuit complexity.For other methods of processing complex contours can not be obtained.
Electrical discharge machining of metals offers several advantages:
- achieve a high surface quality (uniformity, accuracy).Thus, the need for further finishing disappears;
- possibility of different surface textures;
- opportunity obrabatyvaniya very hard surfaces (above 60 units);
- exception deformation fine details due to the absence of mechanical load;
- minimum wear of the anode;
- receiving surfaces of various geometric shapes;
- no noise during processing.
Electrospark processing.The use of
Electrospark processing method found its application in the following:
- piercing holes in workpieces of different hardness;
- notching;
- cutting parts of different hardness;
- Remove worn sections hardened parts;
- grinding surfaces of any hardness;
- parts cleaning after cooking alloys.
Spark erosion has also found its application in the repair of construction machinery.With the help of truncation is made of worn parts, removal of broken fasteners, increasing slightly worn parts.
Finally, be aware that the strength and durability of machine parts, reinforced by the electric method depends largely on the conditions of processing and reinforcing material.
