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Posted on Nov 20, 2020
EDM cutting requires a number of devices and complicated operations, which can lead to a variety of problems. EDM wire has been used in the industry for approximately fifty years. Modern wire EDM machines incorporate CNC control as well as built-in sensors and intelligence, making them more efficient and easy to use.
However, the capabilities and flexibility of electric adaptive control technologies that monitor the EDM cutting process - such as rinsing, wire tension, automatic wire threading, wire wear levels, geometry control, surface quality, water resistance level, and water cooling / thermal stability - have greatly improved over the past fifteen years.
Adaptive control helps the EDM to adapt to changing circumstances by modifying internal parameters. Adaptive control can also help avoid wire breakage and automatically fine-tune the process to optimize speed and performance. In this article, we provide an overview of EDM cutting technology.
EDM cutting is the creation of an electrical discharge between the wire or electrode and the workpiece. As the spark crosses the gap, the material is then removed from the workpiece and the electrode. EDM wire cutting machines can easily machine complex parts and precision components made from hard conductive materials.
In a wire EDM system, conductive materials are processed by a series of electrical discharges created between the precisely placed moving wire and the workpiece. High-frequency AC or DC pulses are driven from the wire to the workpiece with a very small spark gap by an isolated dielectric fluid. Many sparks can be seen at the same time.
This is because true discharges can occur more than a hundred thousand times per second during EDM cutting, and the discharge sparks are 1 / 1,000,000 seconds or less. The heat of each electrical spark, calculated to be around 8000 to 11500 degrees Celsius, erodes a small amount of material, which evaporates and melts away from the workpiece.
These chips are rinsed by a stream of deionized water through the upper and lower rinse nozzles. Without this cooling, the thermal expansion of the parts affects the size and precision of the positioning. Remember, it is the spark's on and off time that is repeated over and over that eliminates the material, not just the movement of electrical current.
The main advantage of EDM cutting is that it can be used on any material as long as it is conductive. Thanks to this, it is possible to process elements made of tungsten carbide or titanium, which are difficult to machine using traditional cutting methods.
Another advantage of EDM is that no mechanical force is applied to the workpiece. Delicate contours are easier to produce because you don't need a lot of cutting force to remove the material. EDM also enables shapes and depths that are impossible to achieve with a cutting tool.
Particularly deep processing, where the tool length-to-diameter ratio would be very high, is a typical application of EDM cutting. Sharp internal corners, deep ribs, and narrow grooves are other specialties of EDM.
Another good reason to use EDM cutting machines is that the surface finish is usually better than with traditional methods. Electrical discharge machining produces surfaces with a fine finish and high precision. In addition, EDM allows users to machine hardened components.
While other machining techniques must be performed prior to hardening the workpiece by heat treatment, EDM cutting can also be applied to the hardened material. In this way, any potential deformation during heat treatment can be avoided.
However, there are many examples where EDM is not the right solution. EDM is a high precision machining method. EDM cutting is a rather slow method compared to traditional machining. Therefore, large-volume tasks are not suitable for this method. At the same time, the electrothermal process requires a lot of energy.
The critical components of the EDM cutting process are wire and dielectric water. The wire is available in several materials and diameters, the most common being 0.010 "or 0.012". The wire used in most applications is made of brass.
If you need more performance, you can choose the galvanized wire, which gives more speed and a better surface finish. The zinc coating allows the wire to tolerate higher heat and helps maintain spark integrity. Annealed, annealed wire - zinc enriched brass wire - can tolerate more heat when cut.
To make EDM wire of a thick part that would not get much of the wire rinse water in the center of the workpiece, use high-efficiency wire. It can withstand heat, keep consistency when cutting, and resists cracking.
Similar to traditional chipping methods, the tool life in EDM cutting is not endless. In sinker EDM, the electrode is also vulnerable to erosion. Because of the tool wear, the electrode has to be replaced regularly. In sinker EDM, it is also necessary to produce the correctly shaped electrodes before the workpiece can be machined.
This is an additional step compared to machining processes with traditional cutting tools. There are numerous examples of companies that have managed to implement electrical discharge machining for their benefit. In many cases, an update to a newer and more modern EDM machine has done the trick.
Without an oil change, you would not drive your car for five years or more. Well, EDM cutting machines still require some care and attention. Preventive maintenance on your home will take 20 hours or more. It typically takes 20 to 30 minutes or less to maintain your EDM per week.
Like spinning the tires, the conductivity parts need to be rotated or indexed, the resin adjusted, the device lubricated, the rollers washed, the cables tested and the AWT checked. Regardless of what EDM system you have, the lack of maintenance can lead to slower cut rates, inaccuracies in size, part piping, wire breaks, rougher surfaces, and ultimately customer service.
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