Graphite is ideal for the machining of large electrodes
Graphite has many advantages over other materials. Graphite is resistant to thermal shock. Graphite is the only material in which the mechanical properties increase when the temperature increases. It has a low CTE for geometric stability. Graphite is easy to machine. It does not melt, but at very high temperatures (3400ºC) it sublimates. Finally, its density is low (five times lower than that of copper) resulting in lighter electrodes. Graphite removes the material better than copper or copper-tungsten while wear is slower.
Hardness
The higher the hardness of the graphite, the harder it is to mechanize the electrode.
Density
As a rule, the wear decreases and the surface finish improve when the density of the graphite increases. High density graphite is used to machine parts in which the geometric shape is critical. On the other hand, the removal of material is often better with less dense graphite.
Grain Size
With very fine grained graphite, the wear decreases and the surface improve. On the other hand, the elimination of material is smaller, block sizes decrease, and the price increases.
Electrical Resistance
The lower the electrical resistance, the higher the thermal conductivity. As a result, graphite has the ability to dissipate the energy accumulated during discharges. As a result, wear decreases with electrical resistance.
Flexural Strength
The higher the resistance to bending, the easier the detailing and the less the wear.
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The wear rate tends to decrease as the discharge increases, unlike copper, whose wear increases at higher currents. Therefore, graphite is ideal for the machining of large electrodes because as the current increases, the roughing time is reduced.
Hardness
The higher the hardness of the graphite, the harder it is to mechanize the electrode.
Density
As a rule, the wear decreases and the surface finish improve when the density of the graphite increases. High density graphite is used to machine parts in which the geometric shape is critical. On the other hand, the removal of material is often better with less dense graphite.
Grain Size
With very fine grained graphite, the wear decreases and the surface improve. On the other hand, the elimination of material is smaller, block sizes decrease, and the price increases.
Electrical Resistance
The lower the electrical resistance, the higher the thermal conductivity. As a result, graphite has the ability to dissipate the energy accumulated during discharges. As a result, wear decreases with electrical resistance.
Flexural Strength
The higher the resistance to bending, the easier the detailing and the less the wear.
