What Is Sinker EDM?

How Does Sinker EDM Work?

Sinker EDM, which stands for Sinker Electric Discharge Machining, is a non-traditional machining process that uses electric discharge to shape conductive workpieces. This is like using a controlled electric spark to carve metal, where the shape of the electrode is accurately replicated onto the workpiece, creating the desired three-dimensional structure.

(1) In an electric discharge machine, a very small gap is set between the working electrode and the workpiece, usually between a few microns and tens of microns. This gap is determined by process requirements and is called the discharge gap.

(2) When the gap between the working electrode and the workpiece is filled with machining fluid (usually a release agent or working fluid), the machining process begins. First, an electric field is formed through the voltage difference between the electrode and the workpiece. Then, under the action of the electric field, the machining electrode (electrode) begins to approach the workpiece surface until the discharge gap is small enough. Then, by controlling the voltage and pulse, an electric spark discharge is generated.

(3) When the voltage increases to a certain level, the air in the discharge gap is ionized to form a plasma channel. This channel leads to the formation of an electric arc, which generates extremely high temperatures, reaching thousands of degrees Celsius. This high temperature will cause the metal on the surface of the workpiece to be melted and evaporated (4) Once the metal is melted and evaporated, the arc will be extinguished. The residual material in the discharge gap is then cooled and cleaned away by the machining fluid. This process is called a discharge cycle. Subsequently, the machining electrode moves, the gap forms again, and the process is repeated.

(5) Controlling the movement trajectory of the processing electrode can achieve precise processing of the workpiece. Through numerical control system (CNC) control, complex shapes can be processed.

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