A machining method typically used for hard metals, Electrical Discharge Machining (commonly known as “EDM Machining”) makes it possible to work with metals for which traditional machining techniques are ineffective. An important point to remember with EDM Machining is that it will only work with materials that are electrically conductive.

With good EDM Machining equipment it is possible to cut small odd-shaped angles, detailed contours or cavities in hardened steel as well as exotic metals like titanium, hastelloy, kovar, inconel, and carbide.
The EDM Process is commonly used in the Tool and Die industry for mold-making, however in recent years EDM has become a integral part for making prototype and production parts. This is seen in the aerospace and electronics industries where production quantities remain low.

Wire EDM Machining Process
Wire EDM machining (Electrical Discharge Machining) is an electro thermal production process in which a thin single-strand metal wire in conjunction with de-ionized water (used to conduct electricity) allows the wire to cut through metal by the use of heat from electrical sparks.
Due to the inherent properties of the process, wire EDM can easily machine complex parts and precision components out of hard conductive materials.

How Wire EDM Works
Wire EDM machining (also known as “spark EDM”) works by creating an electrical discharge between the wire or electrode, & the workpiece. As the spark jumps across the gap, material is removed from both the workpiece & the electrode. To stop the sparking process from shorting out, a non conductive fluid or dielectric is also applied. The waste material is removed by the dielectric, and the process continues.

The History of EDM Machining
The history of EDM Machining techniques goes as far back as the 1770s when it was discovered by an English Scientist. However, Electrical Discharge Machining was not fully taken advantage of until 1943 when Russian scientists learned how the erosive effects of the technique could be controlled and used for machining purposes.
When it was originally observed by Joseph Priestly in 1770, EDM Machining was very imprecise and riddled with failures.

Commercially developed in the mid 1970s, wire EDM began to be a viable technique that helped shape the metalworking industry we see today.
In the mid 1980s, the EDM techniques were transferred to a machine tool. This migration made EDM more widely available and appealing over traditional machining processes.
Today, Wire EDM makes it possible to work with harder materials and metals while keeping the exactness of precision cutting.

Sinker EDM Machining Process
The sinker EDM machining (Electrical Discharge Machining) process uses an electrically charged electrode that is configured to a specific geometry to burn the geometry of the electrode into a metal component. The sinker EDM process is commonly used in the production of dies and molds.

How Sinker EDM works
Two metal parts submerged in an insulating liquid are connected to a source of current which is switched on and off automatically depending on the parameters set on the controller. When the current is switched on, an electric tension is created between the two metal parts.
If the two parts are brought together to within a fraction of an inch, the electrical tension is discharged and a spark jumps across. Where it strikes, the metal is heated up so much that it melts.
Innumerable such sparks spray, one after the other (never simultaneously) and gradually shape the desired form in the piece of metal, according to the shape of the electrode. Several hundred thousand sparks must fly per second before erosion takes place.

Die-sinking EDM Machining
In the case of die-sinking EDM, the required shape is formed negatively in the metal with a three-dimensional electrode. By superimposed movements in the main axes x, y, c, z, the most varied shapes, indentations and cavities are created, such as cannot in part be achieved by any other machining system.
For example, a helicoid cavity or a rectangular hole in one single steel block or the machining of an extremely thin, hardened steel sheet that may not be subjected to any mechanical pressure.