rp graphite electrodes suppliers
Selection of graphite electrode materials for EDM
For graphite materials, the following four indicators directly determine the performance of the material:
(1) The average particle diameter of the material The average particle diameter of the material directly affects the discharge status of the material. The smaller the average particle size of the graphite material, the more uniform the discharge of the material, the more stable the discharge condition, the better the surface quality, and the smaller the loss; the larger the average particle size, a better removal rate can be obtained in rough machining, but fine machining The surface effect is poor, and the graphite electrode has a large loss.
(2) The flexural strength of the material The flexural strength of the material is a direct manifestation of the strength of the material, showing the tightness of the internal structure of the material. High-strength materials have relatively good discharge resistance performance. For graphite electrodes with high precision requirements, choose materials with better strengths as much as possible.
(3) Shore hardness of the material The hardness of graphite is higher than that of metal materials, and the tool loss during cutting is larger than that of metal. At the same time, graphite materials with high hardness have better control of discharge loss.
(4) Intrinsic resistivity of materials Graphite materials with larger intrinsic resistivity will have a slower discharge rate than those with lower resistivity. The higher the intrinsic resistivity, the lower the loss of the graphite electrode, but when the intrinsic resistivity is high, the stability of the discharge will be affected. At present, different suppliers of the world-renowned rp graphite electrode suppliers have many different grades of graphite to choose from. Graphite materials are usually classified according to the average particle diameter. Those with a particle diameter ≤ φ4 μm are defined as fine graphite, particles with a particle diameter of φ5~φ10 μm are defined as medium graphite, and particles above 10 μm are defined as coarse graphite. The smaller the particle diameter, the more expensive the material, and the appropriate graphite material can be selected according to the requirements and cost of EDM. 3. Production of graphite electrode The graphite electrode in the mold manufacturing is mainly made by milling.
From the perspective of processing technology, graphite and copper are two different materials, and their different cutting characteristics should be mastered. If you use the process of processing copper graphite electrode to process graphite electrode, problems will inevitably occur, such as frequent fracture of thin slices, which requires the use of appropriate cutting tools and cutting parameters. RP graphite electrode suppliers processing graphite electrode has greater tool wear than copper graphite electrode. In terms of economy, it is the most economical to use cemented carbide tools. Choosing diamond-coated tools (called graphite tools) is more expensive, but diamond-coated The tool has a long service life, high machining accuracy, and good overall economic benefits. The size of the rake angle of the tool also affects its service life. A tool with a rake angle of 0° will have up to 50% longer service life than a tool with a rake angle of 15°. The cutting stability is also better, but the larger the bevel angle, the greater the processing time. The better the surface, the best processing surface can be achieved by using a 15° bevel tool. The cutting speed during processing can be adjusted according to the shape of the graphite electrode, usually 10 m/min, which is similar to processing aluminum or plastic. During rough processing, the tool can be directly moved up and down on the workpiece. The finishing process is prone to chipping and chipping. Phenomenon, often use a light knife and quick walk.
The graphite electrode will generate a lot of dust during the cutting process. In order to prevent graphite particles from being sucked into the spindle and screw of the machine tool, there are currently two main solutions, one is to use a special graphite processing machine, and the other is to use an ordinary machining center Modification, equipped with a special vacuum device.
Special graphite high-speed milling machine tools on the market have high milling efficiency and can easily complete the manufacture of complex graphite electrodes. The graphite electrodes have high precision and good surface quality. If wire EDM is needed to make graphite electrode, it is recommended to use fine graphite material with smaller particle diameter.
The performance of wire EDM of graphite materials is poor, and the smaller the particle diameter, the higher the cutting efficiency can be obtained, and the occurrence of abnormal problems such as frequent wire breakage and surface streaks can be avoided. EDM parameters of graphite electrode There is a big difference between the selection of EDM parameters of graphite and copper materials. EDM parameters mainly include current, pulse width, pulse gap, and polarity. The following introduces the basis for the rational use of these main parameters.
The current density of graphite electrode is generally 10~12 A/cm2, which is much larger than that of copper graphite electrode. Therefore, within the range of current allowed by the corresponding area, the larger the current selection, the faster the graphite electric discharge machining speed, and the graphite electrode loss The smaller it is, the rougher the surface roughness will be. The larger the pulse width is, the loss of graphite electrode will decrease. However, a larger pulse width will make the processing stability worse, and at the same time make the processing speed slower and the surface rough. In order to ensure low loss of graphite electrode during rough machining, a larger pulse width is usually used, and the value of 100 to 300 us can effectively realize low loss machining of graphite electrode.
In order to obtain a fine surface and stable discharge effect during finishing, a smaller pulse width should be selected. Generally, the pulse width of graphite electrode is reduced by about 40% than that of copper graphite electrode. The pulse gap mainly affects the EDM speed and processing stability. The larger the value, the better the processing stability. It is helpful to obtain better surface uniformity, but the processing speed will decrease. In the case of ensuring stable processing, a smaller pulse gap can be selected to obtain higher processing efficiency, but when the discharge state is unstable, a larger pulse gap can be selected to obtain higher processing efficiency. In graphite electrode electric discharge machining, the pulse gap and pulse width are usually set at 1:1, while in copper graphite electrode machining, the pulse gap and pulse width are usually set at 1:3. In the case of stable graphite processing, the ratio of pulse gap to pulse width can be adjusted to 2:3. When the pulse gap is small, it is beneficial to form a covering layer on the graphite electrode surface, which is helpful to reduce the loss of the graphite electrode.
When rp graphite electrodes suppliers were founded, they established the development strategy of “technology, innovation, leading”, adhering to the business philosophy of “quality first, service first”, after process improvement, quality improvement, and market development, carbon has become Jin, Ji, The largest graphitization processing company in Mongolia. Its main business includes graphite electrode, Shijiazhuang graphite electrode, and Datong silicon carbide. Tel: