Electrical discharge machining (EDM) is a manufacturing process that implements electrical sparks to form a metal shape. Because of these sparks, EDM is also sometimes referred to as spark machining. In this process, the desired shape is cut from the metal when current discharges, or sparks, occur between two electrodes; where the sparking occurs, cuts are made into the metal, creating the desired shape and detaching it from the metal sheet.
There are two main types of EDM — wire and sinker — and several other less common methods, but this article will be focusing on wire EDM. Wire EDM uses a wire as the tool electrode. The wire is wound between two spools and, when in motion, the active part of the wire continually switches — preventing the material from eroding from the wire itself.
Understanding the EDM Process
During the EDM process, a metal part is placed into dielectric fluid, and a wire is fed through the submerged metal component. An electric current is sent through the part to create the sparks that will ultimately help form the desired shape of the component.
When the distance separating the electrodes narrows, it increases the intensity of the electric field, and thus increases the strength of the dielectric fluid. The current more easily passes between the two electrodes under these conditions, leading to the separation of the component from the metal sheet with each spark.
After the currents have passed through and the desired shape has been achieved, manufacturers will sometimes perform a process called “flushing,” using a dielectric liquid to help remove any leftover material or waste from the finished product.
Benefits and Applications of Wire EDM
The wire EDM machine, also known as a “cheese cutter,” offers several unique advantages, making it a popular choice for manufacturers across a range of different industries.
Wire EDM machines are able to carefully remove excess material without exerting a strong cutting force. The process is often automated, meaning it has less chance of causing damage to the workpiece itself. And because wire EDM machines can accommodate hard materials, there is no need for secondary, post-machining thermal treatments. As a result, there is little to no heat stress placed on the shaped part, and less chance that the surface of the part will become distorted.
Wire EDM is most commonly used in mold and die manufacturing processes, particularly for extrusion dies and blanking punches. EDM can be used in everything from prototypes to full production runs, and is most often used to manufacture metal components and tools. The process is best suited for applications requiring low levels of residual stress.
EDM is most commonly used to manufacture parts and components for the automotive, aerospace, and electronics industries.
Unique Advantages of Working With Wire EDM
EDM offers many unique advantages, making it the go-to machining process for producing a variety of different parts and components. First off, EDM’s high precision allows it to create very complex shapes. And its ability to work with hard materials means that it can bring those materials to close tolerances as needed.
Since EDM can handle a high level of complexity, the process can be used to create very small, intricate pieces. And with no direct contact occurring between the tool and the actual part being shaped, it’s easier to achieve a smooth surface finish that is accurate and burr-free.
And, perhaps most importantly in some instances, parts manufactured through EDM are ready for use immediately upon completion of the EDM process.
Why Use EDM?
So, why use EDM?
- EDM can work hard materials and alloys of increasing thickness without compromising the surface finish of the resulting product.
- As a noncontact machining process, EDM can achieve high-quality finishes, thereby reducing the need for post-processing procedures and surface treatments, which are often necessary with other manufacturing processes.
- Because EDM is a computer numerical controlled (CNC) machining process and uses automated software to program functions, the process produces accurate, predictable, and repeatable results during every production run.
- Wire EDM can also accommodate small production runs requiring tight tolerances, as is often the case in the aerospace and medical equipment industries.
- Wire EDM is more cost-effective and time-efficient than other processes available.
Wire EDM Services at Astro Machine Works
Here at Astro Machine Works, Inc., we’re proud to specialize in custom machinery and precision parts. Our team is highly experienced in all aspects of wire EDM, and we have the in-house capabilities to perform EDM services on a wide variety of parts and components.
To learn more, check out our EDM machining page or contact the team today.