Ultra-high-power graphite electrodes use graphite electrodes to replace copper electrodes for mold manufacturing, which greatly shortens the mold manufacturing cycle, improves labor production efficiency, reduces mold manufacturing costs. In recent years, with precision molds high-efficiency molds (the mold cycle The shorter the introduction of), people have higher higher requirements for mold making. Due to the limitations of the copper electrode itself, it has become increasingly unable to meet the development requirements of the mold industry. As an EDM electrode material, graphite has been widely used in the mold industry due to its high machinability, light weight, fast forming, minimal expansion, low loss, easy trimming. It has become inevitable to replace copper electrodes.
1. Characteristics of graphite electrode material
1. CNC machining speed, high machinability, easy trimming. Graphite machining speed is 3 to 5 times that of copper electrodes. The finishing speed is particularly outstanding, its strength is high. For ultra-high (50-90mm), ultra-high Thin (0.2～0.5mm) electrodes are easy to deform during processing. in many cases, the product needs to have a good texture effect, which requires as much as possible to make the overall male electrode when making the electrode, there are various hidden corners when making the overall male electrode, due to the easy-to-dress characteristics of graphite , Which makes this problem easy to solve, greatly reduces the number of electrodes, which copper electrodes cannot do.
2. Fast EDM forming, low thermal expansion, low loss. Because graphite has better conductivity than copper, its discharge speed is faster than copper, which is 3 to 5 times that of copper. it can withstand larger currents when discharging, which is more advantageous for rough EDM machining. At the same time, the weight of graphite is 1/5 times that of copper under the same volume, which greatly reduces the load of EDM. It has great advantages for making large electrodes overall male electrodes. The sublimation temperature of graphite is 4200℃, which is 3 to 4 times that of copper (the sublimation temperature of copper is 1100℃). At high temperatures, change
Ultra high power graphite electrode
The shape is extremely small (1/3~1/5 of copper under the same electrical conditions) does soften. The discharge energy can be transferred to the workpiece with high efficiency low consumption. As the strength of graphite increases at high temperatures, it can effectively reduce discharge loss (graphite loss is 1/4 of copper) ensure processing quality.
3. Light weight low cost. In the production cost of a set of molds, the CNC machining time of the electrode, EDM time, electrode loss, etc. account for the vast majority of the overall cost, these are all determined by the electrode material itself. Compared with copper, graphite's machining speed EDM speed are 3 to 5 times that of copper. At the same time, the extremely low wear characteristics the production of the overall male graphite electrode can reduce the number of electrodes, which also reduces the electrode consumables machining time. All of these can greatly reduce the production cost of the mold
2. Requirements characteristics of electromechanical processing of graphite electrodes
1. Electrode production The production of professional graphite electrodes is mainly processed by high-speed machine tools. The stability of the machine tool should be good, the three-axis movement should be uniform stable without vibration, the rotation accuracy of the spindle should be as good as possible. Electrodes can also be processed on general machine tools, but the process of programming tool paths is different copper electrodes.
2. EDM graphite electrode is carbon electrode. Because graphite has good electrical conductivity, it can save a lot of time in electrical discharge machining, which is one of the reasons why graphite is used as an electrode.
3. Machining characteristics of graphite electrodes Industrial graphite is hard brittle, the tool wear is more serious during CNC machining. It is generally recommended to use carbide diamond-coated tools. When roughing graphite, the tool can be directly up down on the workpiece. In order to avoid chipping chipping during finishing, the method of light knife fast walking is often used.
Generally speaking, graphite seldom collapses when the cutting depth is less than 0.2mm, good sidewall surface quality can be obtained. The dust generated during CNC machining of graphite electrodes is relatively large, which may invade the guide screw spindle of the machine tool. This requires the graphite processing machine tool to have a corresponding device for processing graphite dust, the machine tool must have good sealing performance, because graphite is poisonous. Graphite powder is a chemically sensitive substance. Its resistivity will change in different environments, that is, its resistance value will change, but one thing will change. Graphite powder is a very good non-metallic conductive material. One, as long as the graphite powder is kept uninterrupted in the insulating object, it will be energized like a thin line. However, there is no accurate number for the resistance value, because the thickness of the graphite powder is different. The resistance value of graphite powder used in different materials environments will be different.
You may know that high-purity graphite powder also has conductive applications:
Generally, rubber is insulated. If it needs to be conductive, then conductive material needs to be added. Graphite powder has excellent conductivity lubricating release properties. Processing graphite into graphite powder has excellent lubrication conductivity. The higher the purity of the graphite powder, the better the conductivity. Many special rubber products factories need conductive rubber, so can graphite powder be added to the rubber to conduct electricity? The answer is yes, but there is also a question, what is the proportion of graphite powder in rubber? Some companies use the ratio no More than 30%, this kind of products are on wear-resistant rubber products, such as car tires, etc., the proportion of special rubber factories is 100%, so that it will conduct electricity. The basic principle of conduction is that the conductor cannot be interrupted, just like A wire will be energized if it is broken in the middle. The conductive graphite powder in the conductive rubber is the conductor. If the graphite powder is separated by the insulating rubber, it will be conductive, so the proportion of graphite powder is less conductive. I am afraid that the effect is good.
Graphite powder is a chemically sensitive substance. Its resistivity will change in different environments, that is, its resistance value will change, but one thing will change. High purity graphite powder is a very good non-metal. One of the conductive materials, as long as the graphite powder is kept uninterrupted in the insulating object, it will be energized like a thin line. However, there is no accurate number for the resistance value, because the thickness of the graphite powder is accurate. Similarly, the resistance value of graphite powder used in different materials environments will be different.