Electrical Discharge Machining 101

January 2, 2019
edm machining, wire edm, sinker edm


What exactly does the term EDM (Electrical Discharge Machining) mean? Electrical discharge machining, also known as wire erosion, wire burning, spark eroding, and die sinking, has long been the answer for high accuracy, demanding machining applications where conventional metal removal is difficult or impossible.

EDM electrical discharge machining utilizes controlled electrical discharges to remove or erode conductive material from a blank workpiece material. This process relies on a tool, called the electrode, that is either a thin wire or other conductive material. The tool never actually contacts the workpiece. In a series of rapidly pulsating discharges, the electrical arc “jumps” from the tool to the workpiece.

This non-contact machining allows for extremely tight tolerances and micromachining capabilities. As industries continue to miniaturize their products to meet the demand for ever smaller and more efficient technologies, the need for tighter tolerance machining and manufacturing processes continues to grow. EDM machines typically fall within the following 3 categories:

Sinker EDM

Sinker EDM produces complex shapes without adding stresses into the workpiece and provides low-risk machining solutions for complex components and parts where previous machining was already completed. Sinker EDM differs from Wire EDM as it does not cut completely through the material (unless desired).

Wire EDM

Wire EDM is commonly used when low residual stresses are desired. Wire EDM has no added residual stress because it has no cutting forces. There is little change in the mechanical properties of a material in wire-cutting EDM due to these low residual stresses.

Hole Drilling EDM

Like Sinker EDM, Hole Drilling uses electric current that is carried to the material through a pipe shaped electrode, to erode or burn away conductive materials. The electrode does not touch the material being machined.

To learn more about the basics of EDM electrical discharge machining, check out this article from Engineering.com