Setting the Record Straight With Metal Disintegration Machining | Terminology

In the industry of metal disintegration machining, oftentimes there is misinformation about the terminology that is used to describe the machines, parts, and processes. We at Electro Arc Manufacturing are here to show you what is what when it comes to metal disintegration. Below are terms and proper definitions for processes and machinery-related items in the world of metal disintegration.  People in different areas use different terms to refer to our machine process. Some are misleading.  For our process, a real arc is essential. We don’t burn the material; we vaporize it to turn it into particles.

“EDM” is the correct term for a very different process. Electric Discharge Machining is much more precise than arc disintegration but also very slow. EDM machines are also MUCH more expensive. On the other hand, “MDM” stands for Metal Disintegration Machine, which is what we build. Terms like “spark eroder, spark erosion, spark burner, or spark disintegrator” are misleading and incorrect. Aside from superficial campfire embers, sparks are relatively low-power, momentary electrical effects like those in automotive spark plugs to ignite fuel. By contrast, our arc is a powerful current path operating at very high temperatures like in carbon-arc searchlights. Our arc process literally vaporizes the metal to be removed in a controlled way.
Metal Disintegration Machining (MDM)

Metal Disintegrators or MDM machines are manufactured for the specific purpose of removing broken tools from workpieces. The metal disintegration process removes a tap, bolt, or drill leaving the hole intact and allowing a part to be reclaimed.  MDM removes material very fast. MDM uses a spark erosion process commonly used for destructive cutting. Typical application includes broken tool extraction (taps, drills, reamers, drill bits) metallurgical sample excavation, and bolt removal. There is no faster or efficient or cost-effective method to remove broken tools, studs, or fasteners than MDM.

 

Electrical discharge machining (EDM), also known as spark machining, spark eroding, die sinking, wire burning or wire erosion, is a manufacturing process whereby a desired shape is obtained by using electrical discharges (sparks). Material is removed from the workpiece by a series of rapidly recurring current discharges between two electrodes, separated by a dielectric liquid and subject to an electric voltage. One of the electrodes is called the tool-electrode, or simply the “tool” or “electrode,” while the other is called the workpiece-electrode, or “workpiece.” The process depends upon the tool and workpiece not making actual contact.  When the voltage between the two electrodes is increased, the intensity of the electric field in the volume between the electrodes becomes greater than the strength of the dielectric (at least in some places), which breaks down, allowing current to flow between the two electrodes. This phenomenon is the same as the breakdown of a capacitor (condenser) (see also breakdown voltage). As a result, the material is removed from the electrodes. Once the current stops (or is stopped, depending on the type of generator), the new liquid dielectric is usually conveyed into the inter-electrode volume, enabling the solid particles (debris) to be carried away and the insulating properties of the dielectric to be restored. Adding new liquid dielectric in the inter-electrode volume is commonly referred to as “flushing.” Also, after a current flow, the difference of potential between the electrodes is restored to what it was before the breakdown so that a new liquid dielectric breakdown can occur.

Spark Erosion

Spark erosion is sometimes miscommunicated as being metal disintegrating but it is not. Spark erosion is a form of EDM or electric discharge machining that is a machining technique principally used for hard metals and metals that are difficult to machine using traditional methods. EDM normally operates with materials that are electrically conductive and is designed to erode (remove) intricate depressions or contours from pre-hardened steel negating the requirement for heat treatment to soften and re-harden the steel. We use this method on many different types of metals and alloys, such as Monel, Titanium, Tool Steel, Tungsten Carbide, Tantalum, Super Duplex, and Inconel.

Learn more about the spark erosion process.

Spark Eroder, Spark Burner, or  Spark Disintegrator (You may have heard these referred to as Metal Disintegrators)

Our metal disintegrators are sometimes referred to as Spark Eroders. This is a common term used throughout the UK. However, spark eroders produce sparks in the application, and metal disintegrators do not. So spark eroders are the machines that are used in the electric discharge machining field.

Metal Disintegrator

Metal disintegrators are primarily used for bolt removal, tap removal, stud removal, drill removal, and seized or broken bolts. The process can also be used for roll marking or branding for rebar identification, tool and die work, and metallurgical core sampling. The cutting action of a metal disintegrator is accomplished by creating a series of intermittent electric arcs that break down the hardest metals into minute particles. An electrode, held in the head of the disintegrator, vibrates as it cuts while coolant is pumped through the electrode to wash away the powdered metal.

Metal disintegrators or Metal Disintegration Machining (May be abbreviated as MDM in the machining industry) are primarily used for bolt removal, tap removal, stud removal, drill removal, and seized or broken bolts. Other terms used to describe these machines include bolt eater, tap zapper, and stud buster.
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