Graphite used for EDM machining is an isotropic material with a grain size ranging from a few microns to about 20 microns. In the 1970's, improvements made by graphite manufacturers (isotropic properties, consistent quality, large size billets) combined with the emergence of EDM machines equipped with iso-plus generators, allowed graphite to become the most commonly used material for EDM machining electrodes.Graphite has many advantages that have made it the material most widely used for EDM electrodes.
Graphite is made up of carbon particles that are put through a graphitizing process to produce graphite. The smaller the particle size is, the better the graphite. Graphite can be purchased in big blocks, and then cut up to be machined; or it can be ordered precut or ground into the size you require.
As a leading Chinese graphite manufacturer and supplier, we specialize in providing high quality graphite material, carbon carbon composites and graphite parts. Graphite machines very easily - you can mill it, grind it, turn it, drill it, tap it, even file it to whatever shape you want.You can put it on a duplicating machine or a graphite high-speed mill and cut out complex shapes and forms, and once it's cut you are finished - with no deburring.
Additional advantage of graphite for EDM electrodes:
It has a low coefficient of thermal expansion which assures stability of electrode geometry during electro discharge machining. Sold by grades, graphite cuts approximately three times faster than copper.
It is available in large blocks.
It does not melt, but goes directly from the solid state to the gaseous at 3,400°C, which reduces wear.
Its density is 5 times lower than that of copper, which effects in lighter electrodes.
It leaves a higher metal removal rate than copper with less wear.
It has the unique feature that the wear ratio tends to decrease as the peak current increases.