Why WEDM’s (wire electronic discharge machines) Are So Popular

WEDMWire electronic discharge machine (WEDM) process is also referred to as “spark” machining, “burning”, “die sinking” and wire or spark erosion. It is used to achieve a desired shape in material, via sparks (or electrical discharges). Two electrodes are used to form a constant current. One electrode is known as the “tool”, while the other is known as the “workpiece”.

When two conductors separated by a dielectric (a film of non-conducting liquid), a quick succession of discharge (aka: electrical tension) happens. When the voltage reaches a certain point, the dielectric breakdown occurs, and the ionized channel can be created. In turn, the discharge process can begin, because the dielectric now becomes a local conductive.

During the late 1700’s, Joseph Priestly (and English scientist), made the discovery of an erosive effect caused by electrical discharge. In the early 1940’s, Soviet scientists ( B. and N. Lazarenko) came up with (and acted on) the idea that electrical discharge can be controlled, and used, for machining materials that are conductors of electrical currently. Born, from this idea, is the EDM process.

Advantages

Joseph PriestleyThere are many advantages to wire electronic discharge machining. The least of these, being the fact that it has the ability to create complex cuts/shape when other, more conventional cutting types of tools may fall short. Hard surfaces, such as titanium or steel and other exotic/rare materials are not a hindrance when using an EDM.

In addition, because there is no contact between the workpiece and the tool, fragile material can be successfully machined without distortion or damage.

Disadvantages

There are also a few disadvantages to using a WEDM which include the extra cost and time involved in using this type of equipment. The power consumption is high which adds to the cost of daily operation. As with any oil-based combustible machines, a fire is possible (proper precautions must be in place to ensure safety).

Top WEDM Manufacturers

Wire electronic discharge machines are the main technology used in today’s tool and mold making industry. Companies that are leading this industry include, but not limited to:

Accutex Technologies not only manufactures EDM machines, but also CNC wire cutting machines. This company serves the entire world with its machines, and boasts annual sales of 2 million dollars.

Oscar EDM Company Ltd, a company that is based in Taiwan, specializes in the manufacturing of electrical discharge machines (EDM), including the wire and drilling EDM machines.

Ocean Technologies Co., Ltd, also based in Taiwan, is another leader in exporting EDM machines across the world. In addition, this company is also known for supplying electrode tubes, ceramic guides and other equipment parts.

Belmont Equipment & Technology has all your EDM needs (including coolant drills, filter systems, wire guides and parts for charmilles edm), in addition to excellent customer service.

This company stays at the top by offering the most up-to-date technology, and offering customers a fresh and proactive approach, in meeting all their EDM needs, including increased productivity and money saving options.

Currently, there are several locations in the United States, including California, Illinois, North Carolina and Massachusetts that also serve Mexico and Canadian customers.

GF Machining Solutions is a Switzerland based company, that offers high performance EDMs (including palletizing and clamping systems) globally.

Midway Machine & Instrument Co., Inc. is a leader in manufacturing Charmilles EDM parts, and other machines parts that are vital for running oil fields, space stations and the medical industry. Based in Texas, this company serves Western Europe, North American and, of course, EDM Houston, TX customers.

Shenzhen Industry Co., Ltd, a company based in China, manufacturers grinders, CNC equipment, milling machines and electrical discharge machines (just to name a few).

Wright EDM Parts Co. Ltd. manufacturers’ parts, that are applicable for name brand wire cutting machines, such as Charmilles EDM, Maxi Art, Mitsubishi, Makino and Hitachi. In addition, they also supply drill chucks, ceramic guides and jigs, for use on EDM drilling machines.

The EDM Process – What Electro Discharge Machining Is All About

electrical discharge machiningSpark Machining or Electro Discharge Machining is used on hard metals, especially the processes that are very difficult for traditional techniques to penetrate. Metal is removed from a workpiece by a rapid succession of constant electrical discharges.

As the material is removed from the original workpiece, a continuous flow of fluid (which is usually de-ionized water or dielectric oil) washes it away. This repetitive process continues, until the final shape is created and completed.

A major (and very important) limitation to this process is that it ONLY works with material that is electrically conductive.

Two main methods of Electro Discharge Machining

They are “ram” and “wire”, and the primary difference is the electrode that is used during the machining process.

A “ram” edm cutting application uses a graphite electrode and a traditional tool. This specially shaped electrode is connected to a power source, and is slowly fed into the original workpiece. This entire process is completed under water, and the fluid serves several purposes including:

  1. Flushing away of cut material.
  2. Serving as a coolant, to prevent overheating and potential damage to the workpiece.
  3. Acting as a conductor between the electrode and the material/workpiece.

When a “wire” edm cutting application is used, a tiny thin wire (usually brass) is used as the electrode.

wire electro discharge machine in actionWire electro discharge machining is an alternative to manual and CNC milling methods, and allows the skilled operator to use the edm supplies, to create intricate designs that would otherwise be impossible.

If you were to observe the wire edm cutting process under a microscope, you will see that the wire doesn’t make contact with the metal piece being cut. The path that the wire follows is controlled via computer, and this allows for complex shapes and designed to be created.

A more simplified way to describe this method is to compare it to: a thin piece of wire being stretched between human hands and used to slice a block a cheese, and continuing to do so, until the desired design is completed.

Although similar in concept, when wire is dragged through cheese, the excess cheese is “displaced”, but when using this edm cutting method, the excess pieces that are being cut away are removed.? In addition, this type of cutting method is used in some of the hardest materials in the industry. This type of edm cutting is used, when a low volume of molds are needed as a prototype.

These methods may take a little longer to complete, than traditional cutting methods, but the results are more precise, and you may not have to purchase as many replacement edm supplies, because this slower edm cutting method allows for the tool to last longer.

Modern EDM Machining

Small Hole EDM in actionThe acronym EDM stands for Electrical Discharge Machining. It traces its origin to 1770 when Joseph Priestly first noticed that electrical discharges removed materials from the electrodes during his experiments. The basic EDM process is actually quite simple.

It starts with the creation of a spark between an electrode and the work piece. The spark acts as visible evidence that electricity is flowing. This spark produces intense heat that go up to 12000 degrees Celsius that are carefully controlled to ensure that the heat only affects the surface of the material.

The EDM machining process is usually done in deionized water whose conductivity makes the environment excellent for controlling the entire process. At the same time, the water flushes away all the eroded metal particles besides acting as a coolant.

Modern Electrical Discharge Machining

Modern EDM equipment makes use of equivalent and highly effective tiny lightning bolts in the removal of material. Although this process is considered to be slow in terms of the rate of material removal, the EDM machine is capable of machining multifaceted shapes in hard metals.

In the contemporary world today, makers of jet engine components, dies and molds heavily rely on EDM’s.

The Electric Discharge Machining Process

EDM Machining Process

The process includes a work piece and an electrode. These are both submerged in dielectric fluid and current is allowed to pass through the electrode and the work piece again and again creating tiny plasma zones with temperatures of up to 1000 degrees Celsius.

These high temperatures result in the instantaneous and localized melting of the material in question. Even though the process may seem violent, it only occurs on a small scale such that the metal removal can be precisely controlled.

The electrode in the modern day EDM machinery takes different forms. Wire EDM machines make use of a thin wire that is used to cut with electricity, with the wire moving forward into the hard metal part as a slow-motion saw blade.

Die sinkers, technically referred to as the ram EDM’s, use electrodes that are custom made into 3D shapes. Electric discharge machining then produces a cavity in the opposite electrode.

Other Types Of EDM Machines

There is also the small-hole EDM, often referred to as the ‘hole popper’. In this machine, the electrode is made up of a cylinder that is used to machine a hole that is normally used to provide starter holes for the wire EDM. However, this same technology can be used in machining finished holes in materials that are deemed too difficult to drill.

Modern EDM machines have been customized in a way that assists operators with both simple and complex projects effectively. At the same time, the modernized electric discharge machines can also be used as value added resources in many manufacturing processes.