There are two kinds of graphite electrodes. One is the electrode of the steel mill, specifically the positive electrode of electricity, which generates huge heat energy to melt steel through large current. The other is the electrode of electric spark, also known as EDM electrode. The two versions are the same, but the purpose is different. Here we mainly explain the graphite electrodes widely used in the mold industry for spark discharge.

In the 1960s, copper was widely used as an electrode material, with a utilization rate of about 90% and graphite only about 10%; In the 21st century, more and more users began to choose graphite as electrode material. In Europe, more than 90% of electrode materials are graphite. Copper, once the dominant electrode material, has almost lost its advantages over graphite electrodes. What caused this dramatic change? Of course, graphite electrode has many advantages.
(1) Faster processing speed: in general, the machining speed of graphite can be 2-5 times faster than that of copper; The speed of EDM is 2 ~ 3 times faster than that of copper; The material is less easy to deform: it has obvious advantages in the processing of thin rib electrodes; The softening point of copper is about 1000 degrees, which is easy to deform due to heat; The sublimation temperature of graphite is 3650 degrees; The coefficient of thermal expansion is only 1 / 30 of that of copper.
(2) Lighter weight: the density of graphite is only 1 / 5 of copper. When large electrodes are used for electrical discharge machining, it can effectively reduce the burden of machine tools (EDM); It is more suitable for application in large-scale molds.
(3) Less discharge consumption; Because spark oil also contains C atoms, during EDM, high temperature causes C atoms in spark oil to be decomposed, and then a protective film is formed on the surface of graphite electrode to compensate for the loss of graphite electrode.
(4) No burr; After the copper electrode is processed, it needs to be trimmed manually to remove burrs, while graphite has no burrs after processing, which saves a lot of costs and makes it easier to realize automatic production;
(5) Graphite is easier to grind and polish; Since the cutting resistance of graphite is only 1 / 5 of that of copper, it is easier to grind and polish manually;
(6) Lower material cost and more stable price; Due to the rise of copper price in recent years, the price of isotropic graphite is lower than that of copper. Under the same volume, the price of universal graphite products of Toyo carbon is 30% - 60% lower than that of copper, and the price is more stable. The short-term price fluctuation is very small.
It is this incomparable advantage that graphite gradually replaces copper as the preferred material for EDM electrodes.
With the continuous development of science and technology, many new uses of graphite have been developed.
Flexible graphite products. Flexible graphite, also known as expanded graphite, is a new graphite product developed in the s. The United States successfully developed flexible graphite sealing materials to solve the leakage problem of atomic energy valves. Subsequently, Germany, Japan and France began to develop and produce them. In addition to the characteristics of natural graphite, this product also has special flexibility and elasticity. Therefore, it is an ideal sealing material. It is widely used in petrochemical, atomic energy and other industrial fields. The international market demand is increasing year by year.
In addition, graphite is also a polishing agent and rust inhibitor for glass and paper in light industry, and an indispensable raw material for manufacturing pencils, ink, black paint, ink, artificial diamonds and diamonds.