What's EDM?

 

EDM short for "Electrical Discharge Machining"

As an important precious machining process, it is a special processing method that uses the electro-corrosion effect generated by pulse discharge between two electrodes immersed in the working fluid to remove conductive materials. It is also called discharge machining or electro-corrosion machining.

Graphite material has good conductivity, high melting point, corrosion resistance and is easy to process. During the processing, the loss of graphite electrodes is minimal.

Under the condition of maintaining a constant discharge gap between the graphite electrode and the workpiece, the graphite piece is etched away while the tool electrode is continuously fed to the workpiece, and finally a shape corresponding to the shape of the graphite piece is processed. Therefore, various complex surfaces can be processed by simply changing the shape of the graphite block and the relative movement between the graphite piece and the workpiece.

L.T Graphite, based on years of research and feedback from final customers, specially design and produced for EDM machining mateials, with characteristics:

1) The average particle sizes of the material
The average particle sizes of the material directly affects the discharge condition 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, the better the removal rate in rough machining, However, the finishing surface effect is poor, and the electrode loss is relatively large.

2) The flexural strength of the material
The flexural strength of a material is a direct reflection of the strength of the material, showing the tightness of the internal structure of the material. High-strength materials have relatively good discharge wear resistance. For electrodes that require high precision, materials with better strength should be selected as much as possible.

3) Shore hardness of the material
The hardness of graphite is higher than that of metal materials, and the loss of tools during cutting is greater than that of cutting metals. At the same time, graphite materials with high hardness are better in controlling discharge loss.

4) The intrinsic resistivity of the material
The graphite material with higher intrinsic resistivity will discharge slower than the one with lower resistivity. The higher the intrinsic resistivity, the smaller the electrode loss, but when the intrinsic resistivity is too high, the discharge stability will be affected.
 

L.T Graphite mainly promotes two types of EDM special graphite materials with high cost effective. The technical parameters are as follows:
 

Materials	LTHG-F2	LTJG-1.8
Bulk Density  g/cm3	1.83-1.88	1.78-1.82
Electrical Resistivity  uΩ·m	8-10	≤13
Flexural Strength  MPa	≥50	≥35
Compressive Strength  MPa	≥90	≥65
Ash content  %	≤0.05	≤0.05
Graininess	5-10 microns	15-20 microns