Sinker (or Ram) EDM

Sinker (or Ram) EDM is a specialized machining process used with electrically conductive materials, particularly metals. In this method, a solid, three-dimensional tool electrode (often made of graphite or copper) is employed. The workpiece and the tool electrode are submerged in a dielectric fluid, typically oil or deionized water. This fluid serves to cool the workpiece, flush away eroded material, and provide a medium for electrical discharges to occur.

During Sinker EDM, an electrical voltage is applied between the tool electrode and the workpiece. When these components are brought into close proximity, electrical discharges or sparks occur across the small gap between them. These sparks generate intense heat, which melts or vaporizes small portions of both the tool electrode and the workpiece. Material from the workpiece is gradually eroded, and the shape or feature of the workpiece is formed based on the tool electrode’s design and the CNC (Computer Numerical Control) program that guides the machine.

Sinker EDM is highly effective for creating precise internal features, cavities, and complex shapes within electrically conductive materials. It is commonly used in the manufacturing of molds, dies, and tooling for various industries, as well as in applications where traditional cutting methods would be impractical due to the intricacy or hardness of the material.