The spark intensity is not the only determining factor affecting the surface integrity. This also is dependent on the thermal conductivity of the work metal. High thermally conductive metals will usually have a smaller white layer and less microcracking than a lower conductive material.

The reason for this is due to the energy dissipation throughout the surface of the higher conductive materials. In this case, we can expect for a copper alloy material to have a thinner affected layer with less cracking due to its high thermal conductivity and ductile nature. Contrary to this, a material with a low conductivity value—such as tool steel—can be expected to have a thicker affected layer with more cracking because the spark intensity remains in the spark area longer before the material can dissipate the energy to the surrounding areas.

 Burning carbide creates another concern as this material is very brittle and exhibits higher levels of thermal cracking than other materials. Some consider this material to be highly conductive; however, carbide is comprised of tungsten carbide or silicon carbide particles held together with a cobalt binder. It is this binder that has the high conductivity value and is the area that is affected by the EDM process instead of the carbide itself. The spark energy disintegrates the binder and releases the carbide particles into the gap.            

About First-rate Mold Solution Co., Ltd.
First-rate Mold Solution Co., Ltd. in China, provide industry design,mold design,mold manufacturing,molding analysis,project management service.

 About www.firstratemold.com
our website has a lot of professional knowledges in mold industry in blog and news, also we are interested in CAD/CAM/CAE, such as AUTOCAD,UGNX, PRO/E,CATIA, CIMATRON, SOLIDWORKS, MOLDFLOW and so on,we welcome professional engineer,mold maker and someone who are interested in injection molding,plastic product,injection mold and mold industry to our section of blog and news,we would like to share with them