Due to the high hardness, it is difficult to machine tungsten carbide die. Especially when the machining accuracy is high, or the surface is very complex, it is more difficult and time consuming. In recent years, there are three ways to machining tungsten carbide die, which are electro machining, grinding and lapping.

 

 

Electric Discharge Machining(EDM)

In precision mold manufacturing, EDM is only used as rough machining process. On the choice of electrode materials, the copper electrode is mainly used for processing general steel dies. The comprehensive performance of the Cu-W electrode material is good. Especially, when processing, the consumption of electrode in the corner R part is less than that of the copper electrode, and the thermal stability and dimensional stability are the highest. It is more suitable for finishing and the complex shape of the electrode section, the long flake deep groove and small diameter electrode, which is suitable for the processing of tungsten carbide die.

 

Ag-W electrode has better performance than Cu-W electrode, which is suitable for processing tungsten carbide. However, it has high cost and less supply. The design of the electrode structure is mainly 2 forms: the integral structure and the combined structure. Generally, the integral structure is selected. The composite electrode is often used in the machining of the complex die with complex shapes.

 

Grinding and Lapping

Usually, the diamond grinding wheel uses organic binder and metal binder. The grinding wheel of organic binder has good self-sharpening property, of which the workpiece roughness can be up to Ra=-0.1um. Because the bonding strength is low, its service life is short. The grinding process can go on without coolant, and the manufacturing process is simple.

 

The diamond grinding wheel with metal binder has no roughness of Ra =0.8 um. Rough grinding of diamond grinding wheels with metal binders is used to finish grinding wheels that can be used as organic binder. In order to improve the life of the organic binder grinding wheel, a diamond with a large particle with branched fork is formed, which is firmly bonded together by 3~10 small granular diamond. This particle is more tightly combined with the binder, thus improving the service life of the grinding wheel.

 

Lapping of the die can remove the grinding marks left on grinding that not only affect the surface quality of the parts but also produce stress concentration. And, lapping can also be grind out a damaged WC on the surface after grinding, so that the die life can be improved by 20%~30%. In order to meet the high precision requirements of the tungsten carbide die, grinding is also needed. Grinding rod or grinding block can be made of cast iron, steel and other materials.