Filtration Technology of Wire Electric Discharge Machining (WEDM)

The filter plays a very important role in LS-WEDM, and its quality directly affects the accuracy, smoothness, processing stability, processing speed of the processing workpiece.

To maintain high-speed and stable WEDM, the key is to design a set of wire cutting EDM filters that can adapt to high-speed wire-cutting and process a large amount of metal powder generated during processing in time. It is not very important that how much metal powder can be filtered out by the filter, the key to solving problems is to quickly, effectively and thoroughly filter out the metal powder produced during the WEDM processing from the working fluid. A large number of studies by TAGUTI company show that if the metal powder cannot be filtered out in time, the working fluid will quickly lose the ability of high-speed wire cutting, the surface roughness and the dimensional accuracy and processing speed of the workpieces will be affected.

Test machine: SODICK’s WEDM AD360

Test filter: TAGUTI’s Wire EDM Filter YT-19

In response to the above situation, TAGUTI doubled the number of EDM filters in the original filter circuit (if 2 filters were installed before, now we install 4 filters).

When in use, 4 electrical processing filters are installed in two filter circuits, and solenoid valves are added to the two filter circuits to control the opening and closing of the corresponding circuits respectively.

When cutting large-thickness workpieces or initial processing, the installed 4 EDM filters filter simultaneously through 2 circuits, which can effectively improve the filtration speed. In the case of ordinary processing, only one of the filter circuits is used for filtering to ensure the stability of the wire cutting process.

The filtration system loaded with 4 electrical processing filters is directly assembled in the working fluid storage tank, so that the filtration system can always be kept working under a certain working pressure, forcing the metal powder to be filtered out through the filtration system. In addition, the multi-layer composite filter materials with a 33% larger filter area are used, which greatly improves the filtration precision and filtration speed.

According to our test, using 2 times the amount of EDM filter can improve the filter system and prolong the service life of filter system parts by 2.4 times, effectively reduce the downtime caused by replacing the EDM filter and the processing cost.

The metal powders in the working fluid are filtered with high precision and large flow, which means that only clean working fluid flows between the channel of the brass wire and the workpiece, this can ensure the stability of the electrical conductivity of the working fluid, so that the brass wire can be processed by electrical discharge under the control of ideal discharge parameters without any obstacles and interference, thereby ensuring the finish of the workpiece.

SODICK’s WEDM pulse power supply has the ability to increase the discharge voltage and higher limit amplitude. According to the material and thickness of the workpiece to be processed, we can select the best cutting parameters in the optimized processing database, including discharge voltage, processing current and pulse frequency and amplitude, then the pulse power supply can generate suitable pulse power waveforms to ensure high-speed and stable WEDM.

The clean working fluid can also greatly improve its cooling efficiency and reduce the breaking of brass wire during processing. This is especially important for cutting large thickness and large taper workpieces. Using the improved wire cutting filter system also has the following advantages:

  1. The discharge gap between the workpiece and the brass wire is an area where the metal powder is not expected to have a negative effect. Because when the metal powder comes into contact with the brass wire, unwanted sparks will be generated, which will cause multiple discharge corrosion to the brass wire and it is easy to break the brass wire.
  2. If the metal powder in the working fluid is not completely filtered, exists in the working fluid for a long time, it will wear the sealing parts of the working fluid pipeline. Over time, it will destroy its sealing, and affect the processing effect and increase the downtime of replacement. The improved filter system can also enable the wire EDM machine to perform high-precision wire cutting on large and heavy workpieces on the large workbench configured.

Nowadays, the workpieces are getting bigger and bigger, the requirements for machining accuracy are getting higher and higher, and the labor cost is rising. So compared with the traditional wire cutting filter, the improved wire cutting filter system will be more able to meet the needs of users, because it has many essential improvements!

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