1.Bending strength of material
The bending strength of the material is the direct embodiment of the material strength, which shows the compactness of the internal structure of the material.The materials with high strength have relatively good resistance to discharge.For high-precision electrodes, try to choose materials with good strength.
2.Inherent resistivity of materials
According to our statistics of material properties, if the average particles of the material are the same, the discharge rate with high resistivity will be slower than that with low resistivity.For materials with the same average particle size, the strength and hardness of materials with low resistivity will be slightly lower than those with high resistivity.That is, the discharge speed and loss will be different.Therefore, it is very important to select materials according to practical application.Due to the particularity of powder metallurgy, the parameters of each batch of materials have their own representative values and have a certain range of fluctuations.However, the discharge effect of the same grade graphite material is very similar, and the difference of application effect caused by various parameters is very small.The selection of electrode is directly related to the effect of discharge, and to a large extent, the correct selection of materials determines the final condition of discharge speed, machining accuracy and surface roughness.These four kinds of data represent the main discharge performance of the material and directly determine the performance of the material.
3.Shaw hardness of materials
In the subconscious understanding of graphite, graphite is generally considered to be a relatively soft material.However, the actual test data and application show that the hardness of graphite is higher than that of metal materials.In the special graphite industry, the general hardness test standard is Shaw hardness measurement, which is different from metal.Because of its layered structure, graphite has excellent cutting performance in the cutting process.The cutting force is only about 1 big 3 of that of copper, and the machined surface is easy to deal with.However, because of its high hardness, the loss of cutting tools will be slightly larger than that of metal cutting tools.At the same time, the high hardness materials have a good control on the discharge loss.
4.Average particle diameter of material
The average particle size of the material directly affects the discharge status of the material.
The smaller the average particle of the material is, the more uniform the discharge is, the more stable the discharge condition is, and the better the surface quality is.
For forging and die-casting moulds with low surface and precision requirements, coarse-grained materials such as ISEM-3 are generally recommended.
For electronic moulds with high surface and precision requirements, it is recommended to use materials with an average particle size of less than 4 μ m to ensure the accuracy and surface finish of the molds.
Post time: Jun-08-2022
