1. The flexural strength of materials

The flexural strength of a material is a direct reflection of its strength, indicating the tightness of its internal structure. Materials with high strength have relatively good resistance to loss during discharge. For electrodes with high precision requirements, it is advisable to choose materials with better strength. For example, TTK-4 can meet the requirements of general electronic connector molds, but for some electronic connector molds with special precision requirements, TTK-5 material with the same particle size but slightly higher strength can be selected.

2. Shaw hardness of materials

In the subconscious understanding of graphite, it is generally considered a relatively soft material. But actual test data and application situations show that the hardness of graphite is higher than that of metal materials. In the special graphite industry, the common hardness testing standard is the Shore hardness measurement method, which has a different testing principle from that of metals. Due to the layered structure of graphite, it has excellent cutting performance during the cutting process, with a cutting force of only about 1/3 of that of copper material. The surface after mechanical processing is easy to treat.

However, due to its high hardness, the tool loss during cutting is slightly greater than that of metal cutting tools. At the same time, materials with high hardness have excellent control over discharge losses. In our EDM material system, there are two materials available for materials with the same particle size that are widely used, one with slightly higher hardness and the other with slightly lower hardness, to meet the needs of customers with different requirements. For example, the average particle size is 5 μ The materials of m include ISO-63 and TTK-50; The average particle size is 4 μ The materials of m include TTK-4 and TTK-5; The average particle size is 2 μ The materials of m include TTK-8 and TTK-9. Mainly considering the bias of various types of customers towards discharge and mechanical processing.
3. The average particle diameter of the material

The average particle diameter of a material directly affects its discharge condition. The smaller the average particle size of the material, the more uniform the discharge of the material, the more stable the discharge condition, and the better the surface quality.

For forging and die-casting molds with low surface and precision requirements, it is usually recommended to use materials with coarser particles, such as ISEM-3; For electronic molds with high surface and precision requirements, it is recommended to use an average particle size of 4 μ Materials below m are used to ensure the accuracy and surface smoothness of the processed mold. The smaller the average particle size of a material, the smaller its loss, and the greater the interaction force between ion groups. For example, ISEM-7 is usually recommended in precision die-casting molds and forging molds, as it is sufficient to meet the requirements; But when customers have particularly high precision requirements, it is recommended to use TTK-50 or ISO-63 materials to ensure smaller material loss, thereby ensuring the accuracy and surface roughness of the mold.

Meanwhile, the larger the particles, the faster the discharge speed, and the smaller the loss during rough machining. The main reason is that the current intensity during the discharge process varies, resulting in varying levels of discharge energy. But the surface smoothness after discharge also varies with the variation of particles. Graphite material

4. The inherent resistivity of the material

According to our company's statistics on the characteristics of materials, if the average particles of the materials are the same, the discharge speed of materials with high resistivity will be slower than those with low resistivity. For materials with the same average particle size, materials with low electrical resistivity will have slightly lower strength and hardness compared to materials with high electrical resistivity. That is, the discharge speed and loss may vary. Therefore, it is very important to choose materials according to the actual application needs.

Due to the particularity of powder metallurgy, each parameter of a batch of materials has its own representative value with a certain fluctuation range. However, graphite materials of the same grade have very similar discharge effects, and the differences in application effects caused by various parameters are very small. Graphite material

The selection of electrode materials directly affects the effectiveness of discharge, and to a large extent, the appropriateness of material selection determines the final situation of discharge speed, machining accuracy, and surface roughness

Mastering the above points is of great significance for us to distinguish the grade of graphite materials

Zhuzhou Yuanhang Industrial Furnace Technology Co., Ltd. is a new type of technology enterprise that specializes in providing complete solutions for various heat treatment equipment. The company currently focuses on producing various specifications of high-temperature graphitization furnaces and carbonization furnaces, providing customers with high-tech, high-quality, and cost-effective heat treatment equipment.