b. The electrode loss is large. When the electrode loss is too large, the contouring accuracy and dimensional accuracy of the processed part will be seriously affected. The cause of the large electrode loss should be correctly analyzed. The quasi-medium pulse width of the electrical gauge is the main parameter for controlling the electrode loss. In the case of large electrode loss, it should be considered whether the selected pulse width value is too small. In the case of high precision requirements, it should be considered whether the electrode material selected can meet the requirements of low loss processing. Check if the positive and negative polarity of the processing is reversed. Whether the loss is excessive due to excessive machining current during small electrode machining. If the oil pressure is too high, the local loss of the electrode will be too large and should be adjusted appropriately.
c. The discharge state is unstable. The unstable discharge state is an abnormal phenomenon that can be found during the processing and should be dealt with in time to avoid the consequences of affecting the quality of the processing. When the discharge state is unstable, there will be a series of corresponding performances, such as the spark color is red, white smoke, low sound and boring, the discharge is concentrated in one place, the current and voltmeter hands are not evenly oscillated, the servo dial indicator is swinging back and forth, etc. . When these conditions are found, the influence of the electrical parameters should be considered first, such as whether the discharge time is too long, whether the slag height is insufficient, whether the current, the pulse width is too large, and whether the pulse gap is too small. Secondly, it should be considered whether there are debris or burrs in the processing part. Again, it should be considered whether the selection of the pressure and method of flushing is reasonable.
d. The electrode is deformed. Deformation of the electrode is more common in the processing of thin electrodes. This deformation is mainly thermal deformation. Secondly, the servo pressure is too large. For the processing of such electrodes, the discharge energy should not be too large, and the heat during the processing should not last too long. Therefore, the current cannot be selected too much, the discharge time should be short, and the flushing oil should be sufficient. When designing the electrode, the electrode of other processed parts should have sufficient strength except for the thin part of the structure itself.
e. “Cannoning†occurs in the machining of the hole. The gas generated during the process is concentrated at the lower end of the electrode or inside the oil cup. When the gas is ignited by the electric spark, it will be discharged like a "shooting gun" and it is easy to displace the electrode and the die. This situation is more likely to occur during oil pumping. Therefore, when using the oil cup for the hole machining, pay special attention to the exhaust, properly lift the knife or open the air groove and exhaust hole around the top of the oil cup to facilitate the discharge of the accumulated gas.
(5) Abnormal processing caused by human accident. An abnormality in processing quality due to human care can occur during production. These phenomena mainly occur on the EDM operator, such as setting the coordinate number incorrectly, setting the depth incorrectly, reversing the electrode clamping direction, taking the wrong electrode, reading the wrong drawing, editing the NC program, etc. These problems are not technical, but the lowest level of human error. But sometimes the consequences of some minor mistakes are very serious. You should try to avoid making mistakes and constantly improve your skills.
3 Conclusion <br> <br> prevent the occurrence of abnormal electrical discharge machining problem has important significance to improve the quality of the mold. The impact of each link in the processing on the processing quality should be correctly analyzed, each link should be grasped, and each processing detail should be paid attention to to ensure the final processing quality.
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PVA sponge polishing wheel adopts special synthetic resin to enhance its wear resistance
And the grinding force, by the existence of special air hole, can quickly eliminate the dust, no packing and hair
Heat phenomenon, avoid heat burn workpiece, suitable for long time grinding work. The binder is soft and slow
Impact, no deep blemishes on the grinding surface.
Use of PVA grinding wheel :1. It is easy to heat up when using general sand flower and sand cloth
Used for grinding stainless steel, aluminum, copper, iron, wood, gemstone, marble, glass, graphite
Products, urea products and leather, etc. PVA sponge grinding wheel is the most suitable. In addition, it can be eliminated
Burr, dirt, rust, etc.
2. Using PVA sponge grinding wheel, you can get beautiful grinding surface and saving after a short time of work
Omitted number of projects. For example, all kinds of metal grinding, copper mixing cylinder (centerless polishing), watchcase,
Grinding of watchband, gemstone and marble before plating or polishing.
Mounted Point,Polishing Mounted Point,Grinding Mounted Points,Mounted Point Grinding Wheel
Henan Jinlun Superhard Material Co., Ltd , https://www.jinlunsuperhard.com