Copper is more efficiently cut on WEDM machines, which makes it cut much faster than graphite in WEDM. Highly detailed electrodes,

which were formerly manufactured on surface grinders, required many hours of highly skilled labor. The use of copper and WEDM to produce these electrodes has dramatically changed EDM%20machining.

Copper is less likely to cause pits in the steel workpiece. The tendency of any electrode to “DC arc” is the curse of EDM. When the flushing is poor, machining conditions are ripe for a short circuit to occur in the EDM process, causing the tell-tale pits in the workpiece. Copper is much more forgiving and less likely to DC arc.

Copper is usually used to produce a finer finish in the steel. Copper electrodes are sometimes polished to reproduce the fine finish on the mold surface. Newer EDM machines have polishing settings that can produce mirror finishes, and usually copper is used.

Copper is the best for small cavities, especially where polishing is difficult. Because of it’s resistance to pitting and the finer finishes attainable, copper is often used in these applications. Adding tungsten to copper increases it’s excellent wear characteristics, but also is very difficult to machine.

Copper can be machined by coining. In this process, the copper is stamped with an image, just like a coin, and then used as an EDM electrode. This can be an excellent application for designs such as logos.

Copper is clean to machine and leaves no annoying dust. Also, tellurium copper leaves much less burr than pure copper.