Sinker EDM: Process And Applications

EDM, an acronym for electrical discharge machining, dates back to the late 18th century and the pioneering work of Joseph Priestly (1733-1809), an English clergyman and physicist. Today, it has evolved into a more sophisticated form of metalworking. Among the various types currently available for metal fabricators and manufacturers is Sinker EDM.


This type of EDM utilizes an electrically charged electrode. Commonly made from graphite, brass or copper tungsten, this tool burns into the specified metal component a specific shape. Literally, the process involves the sinking of the shape into the workpiece submerged in oil. This action does not cut entirely through the workpiece. Instead, electrical sparks strike the component and nip out small pieces. This produces the desired shape.


Sinker EDM can tackle some of the most unyielding material available today. It can take difficult material and form it easily into intricate shapes. The material it shapes easily includes:

  • Carbide
  • Hardened steel
  • Inconel
  • Titanium

However, it cannot be used to cut and shape both hard and soft ferrite materials because they are not electrically conductive. The same applies to magnetic materials if they are heavily bonded using epoxy.

Size and weight do not affect the capabilities of this technology. Small or hefty, this method can handle them all. Applications involve intricate shaping, tight tolerances and/or tight corner radii. This technology also is relied on to manufacture production dies and molds.

Sinker EDM

If a company wishes to handle complex situations such as producing precise cavities or specialized cutting, the answer may not lie in conventional methods or techniques. A more effective way is to use sinker EDM. This is a very efficient technology worth investing if a shop wishes to expand beyond the traditional approach and into the versatile and stress-free actions of EDM. Not only can preciseness of production become commonplace but also the capability to produce both stamping dies and injection molds quickly and efficiently.

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