Electrical Discharge Machining (EDM)

EDM, or electrical discharge machining, is capable of machining complex shapes in hard materials. The process includes an electrode and a workpiece, both submerged in dielectric fluid. Electrical current flows between the workpiece and electrode, repeatedly creating tiny plasma zones that instantaneously melt and remove the material. The electrode in EDM takes different forms. Wire EDM machines use a thin wire to cut. Ram EDM machines, or “die sinkers,” use electrodes that are custom machined into 3D shapes. The EDM process produces a cavity in the part that is the opposite or female version of the “male” electrode form. Similar to the ram EDM machine is the small-hole EDM machine, or “hole popper.” On this machine, the electrode is a cylinder used to machine a hole. 

sinker edm process

Cool Tricks: How to Photograph Sinker EDM

Sometimes it takes a little extra effort and ingenuity to solve a problem. In the case of the February 2020 cover of Modern Machine Shop, it took a lot of each — and a cheap plastic spaghetti container.

Inside the Sinker EDM Process, One Spark at a Time

Successful sinker EDM operations rely on understanding the relationship between each individual spark, the electrode and the workpiece. 
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EDM and the Precision Parts Industry

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