For those that are not machinists or not familiar with all the options that can be used to cut and shape metals, wire EDM may be a relatively unknown process. In fact, many of the common objects people work with all the time are produced by this method as it is efficient, accurate and highly effective.
EDM actually stands for Electrical Discharge Machining but is sometimes called spark machining. Both of these names are very accurate as the process does use sparks (electrical discharge) to create the shape or remove material from the metal in a specific pattern.
How it Works
Wire EDM is a very precise process that is not actually a new technology. In fact, it was first used in the 1940s and the machine to complete the job was created by two Soviets, although it was not the same advanced technology as used today.
The process is actually simple and is one that people can easily understand. There is an electrode that is used to create an electrical spark that passes from the electrode to the metal workpiece. The spark produces energy in the form of heat. The spark can reach temperatures in excess of 8000 degrees Celsius and up to 12,000 degrees Celsius.
These temperatures are carefully selected to match the melting point of the metal. The spark is controlled to maintain this temperature and only to be on the specific part of the metal where removal is required. By controlling the flow of electricity through the electrode, the heat is controlled and only the surface layer is melted.
At the same time, deionized water is used to flush the surface during wire EDM. The water forms the dielectric component and also removes the metal flakes and particles while instantly cooling the surface after the cut is complete.
Important Considerations
The use of wire EDM is ideal in many applications. It is commonly used to create dies and molds, but it can also be used for large scale production applications as well.
This is a very good option when the workpiece is heat treated prior to processing. The controlled nature of the process doesn’t impact the heat treatment and prevents the need to re-work the piece to regain lost strength that can occur with other cutting and shaping methods.
Additionally, as there is no pressure on the workpiece during the process, this is an ideal choice for fine work on thin or small pieces. It is also a great option when precision holes are required as the system allows for complete control of depth and diameter.