ABOUT JAMESTAN ENGINEERING

What is Wire and Spark Erosion and Why is it Important?

Wire and spark erosion, also known as electrical discharge machining (EDM), is a machining process that uses sparks to erode metal in a precise and controlled manner–so precise that each Spark will remove material smaller than the thickness of a human hair. Machining products in this way, such as hard-wearing, intricate tools, is a much simpler process than conventional means. In its most basic form, EDM is achieved using an electrode, a dielectric fluid and a conducting material. The shape of the electrode will determine the condition of the space to be eroded, while the dielectric fluid will act as a resistor to induce the sparks.

This type of machining has many names, partly due to how versatile it is. Some of these include die sinking, spark machining and wire erosion. The latter term comes from the fact that the more nuanced methods of EDM use thin wires to remove material to create intricate contours, such as the teeth in gears. Regardless of the EDM method used, however, machinists typically don’t need to treat the material with heat to soften it, making the process very efficient when resizing and cutting metal. This is true for a range of metals, including steel, titanium, Kovar and Hastelloy.

What is Wire and Spark Erosion and Why is it Important?

There are myriad reasons why wire and spark erosion is the ideal machining method for your upcoming project. First and foremost, EDM has proven to be one of the most precise solutions for machining metal over the years, doing the job of producing complex configurations that much simpler when compared to traditional methods. This accuracy is sometimes known as the machining tolerance, and when the precision of the production process is this good, creating identical parts that don’t deviate from the prescribed dimensions becomes a much more realistic aim.

Likewise, very precise machining with EDM allows companies to make smaller parts without running the risk of damaging the material. When working on weaker materials, the risk of causing distortions increases. That’s why the non-contact methods offered by EDM are so important. The machining tool here uses sparks to shape the workpiece, rather than friction, and, therefore, doesn’t expose the material to as much force as conventional solutions. Furthermore, this indirect, precise method of machining widens the scope of what can be achieved in manipulating hard metals, including producing tiny holes and tapered openings, as well as a more refined surface finish.

How is Spark produced in EDM?

EDM is a relatively simple process that involves three main components: a conducting material, a dielectric fluid and an electrode. The electrode can take the form of any shape, from a simple square to a complex polygon. Likewise, the conducting material, which is the piece to be worked on, can be one of several metals, including many types of alloys. A charge will flow between these two components when power is introduced, but this alone will not produce sparks. To create a spark that jumps from the electrode to the material, the material needs to be submerged in a dielectric fluid, which will typically act as a resistor to the flow of charge.

When the power is increased intermittently, this dielectric fluid will correspondingly breakdown and allow charge to flow briefly across it–in the form of a spark. The abruptness of this change from non-conductivity to conductivity is what causes these brief flashes of light, which are extremely hot bursts of energy striking the surface of the material to “chip” away at it. They are so hot that they create areas of hot plasma that need to be flushed out by the dielectric fluid–one of its other functions in this scenario.

What type of industries uses Wire and Spark Erosion?

Wire and spark erosion machining is used in a wide range of industries to produce intricate parts to exacting specifications, including those that demand low volume, high-quality components. Teams competing in high-level motorsports, for instance, often turn to EDM to produce the parts necessary to get the most out of their vehicles in a reliable manner. Features such as gearboxes, suspension arrays and various testing components all require the precision offered with this method of machining. Other highly technical industries that benefit from wire and spark erosion include aerospace, electronics and car manufacturing.

The quick turnover from designing the electrodes to manufacturing the components means that EDM is now also ideal for prototyping, which again suits industries such as motorsports and aerospace, where testing new designs is a large part of what they do. Elsewhere, EDM is equally well utilised in toolmaking and creating moulds, as well as intricate surgical equipment. In the latter case, because EDM uses more corrosion-resistant materials than traditional methods of machining, it’s ideal for medical applications. The ability to shape more durable and corrosion-resistant materials with EDM means that the energy industry also relies on this method to create turbines, drills and flow diverters to a long-lasting specification.