EDM Wire Cut Machine also known as Wire Cut Machine or Wire EDM Machine. EDM wire cut uses a spool of a thin metallic wire as an electrode such as brass wire, zinc coated wire and zinc enriched wire to cut a programmed contour in a electrically conductive material or a metal workpiece. The diameter of EDM wire is between 0.05mm (0.002") to 0.33mm (0.13") and the wire tensile strength is more or less than 900N/mm² (130,000psi) depends on the type of wire.
EDM brass wire
Photo by Landmark Technology Co., Ltd
The wire EDM machine is generally used when the cut goes all the way through the workpiece and the electrode will be electrically energized to slice through the metal workpiece. The wire is pulled through the workpiece being cut and cooled by a dielectric fluid or deionized water which acts as a coolant. During machining process, the wire itself will be traveling from wire spool into the wire bin reel and the traveling distance will be controlled by the machine program.
EDM Wire
Photo by XACT Wire EDM Corp
The electrode and the workpiece are either fully submerged, or flushed with a deionized water. To start machining it is first necessary to drill a hole in the workpiece or start from the edge. When the electrically energized wire approaching the workpiece the electrical discharge or spark will be created. The spark will jump to the workpiece which will erode some small amount of workpiece and flush away by the deionized water to form the spark gap between the wire and the workpiece. The spark gap size can be controlled as small as 0.0127mm (0.0005").
EDM wire cut possible machining shapes
Photo by Hong Kong Polytechnic University
The Wire EDM machine uses rapid and repetitive electrical discharges to create more and more spark gap. The spark gap will allow the wire to advance further until the workpiece is cut through. The EDM is a non-contact cutting process, the wire itself does not touch the workpiece and the actual cut is done by the spark. This eliminates machining forces that can cause distortion. The quality of the product depends on the spark gap size, the smaller the spark gap size, the smoother the surface, but the machining time is much more longer.
EDM wire cut produces excellent dimensional accuracy with a high quality surface finish, suitable for cutting intricate shapes or irregular shapes and tight radius contours to create complex dies and other tools from extremely hard materials. It is ideal for cutting hardened materials above HRC 38.
CNC EDM Wire Cut Machine
Photo by CNC Machinery, Inc.
Most EDM machines are controlled by computer numeric control (CNC). The CNC wire cut machine is an equipment to produce very fine cuts in the metal workpiece. The cut can be as thin as 0.0127mm (0.0005"). The accuracy of the machine could be as precise that it can produce a tolerance of less than 10 micron. This kind of machine is an essential requirement for making precision dies or moulds. Wire EDM requires no special special fixtures and in most cases the machine can run unattended. This makes the EDM wire cut is one of the most cost-effective process, allowing you to reduce inventory and fast delivery dates. This will contribute to improve cash flow and reduce operating expenses.
EDM Wire Cut Machine
What is EDM?
What is EDM? The EDM is stands for Electrical Discharge Machining or Electrical Discharge Machine. Other popular name for EDM is Electro Discharge Machine. There are two most popular EDM machine, Ram EDM Machine and EDM Wire Cut. Ram EDM also known as, Sinker EDM, Die Sinker, Vertical EDM or Plunge EDM. Ram EDM divided into two main categories, Conventional EDM and CNC EDM. EDM is a non conventional machining method to remove unwanted material from electrically conductive workpiece or metal. EDM is a machining method primarily used for hard metals, super-tough alloy, hardened materials or cutting delicate cavities that would be impossible to machine with conventional machining method such as milling, drilling, grinding or with other type of conventional machine tools. Some of the EDM applications are machining aerospace alloys such as titanium, inconel, & hastalloy, removing broken taps, drills, & bolts and machining of carbide dies and tools.
Conventional EDM or EDM Ram Type
How EDM works? Basically, the EDM process is simple the unwanted material removes by use of recurrent sparks applied to a hard metal. An electrical discharge is created between an electrode and the workpiece known as spark to create spark gap or spark erosion between the electrode and workpiece. For Ram EDM, a special brass will be fabricated into a desire shape and use it as an electrode. The brass will be attached to the EDM machine and use it to machine the workpiece under carefully controlled conditions. Read this blog post about Wire Cut EDM for more details information.
CNC Electrical Discharge Machine / CNC EDM
Photos by Creator Precision co., Ltd
During EDM process, the current will be switched on and off by moving the electrode up (current off) and down (current on) to control the spark gap. When the current is switched on the spark jumps across the gap and the small amount of unwanted material is removed from the workpiece to allow the electrode to be moved through the workpiece. The electrical spark are very short in duration, approximately 1 microsecond to 1 millisecond each. This process repeats its self over and over again until the electrode is slowly advanced deeper and deeper into the cut. The path of the electrode is typically controlled by a numerical controller (NC) for NC EDM machine or computer numerical controller (CNC) for CNC EDM machine, which allows a desire shapes to be produced.
The spark always takes place in the dielectric of deionized fluid which acts as a coolant and when the current is switch off the deionized fluid will flushes away the eroded particles from the workpiece. In fact, the electrode itself does not touch the workpiece being cut because the actual cutting is being done by the electrical discharge or spark created between the electrode and the workpiece.
