The precision that can be achieved by precision machining is one of the important indicators to measure the level of a country’s manufacturing technology, and with the continuous improvement of machining accuracy, the requirements for the surrounding environment of the machine tool are getting higher and higher, in addition to the hydraulic and pneumatic pressure in precision machining. In addition to the fluctuation of the working environment, the temperature, cleanliness and vibration of the working environment also have a great influence on the processing quality. In order to improve the precision of the machined surface of precision mechanical parts, multiple cutting techniques have emerged.

Multiple cutting technology is the fundamental means for WEDM to improve the machining accuracy and surface quality of precision mechanical parts. Generally, the first cutting is used to form, the second cutting to improve the accuracy, and the third or more cutting to improve the surface quality.

During the multiple cutting process, the first cutting requires a large pulse energy to obtain a higher cutting speed. At this time, during the multiple cutting process for the quality of the machined surface of the precision mechanical parts, it is first required that the machine tool table must have a high cutting speed. The geometric accuracy and motion accuracy of the electrode wire are required to ensure the constant and stable spatial position of the electrode wire. Of course, in order to achieve the purpose of stable multiple cutting, it is also necessary to improve the high-frequency pulse power supply and systematically study the multiple cutting process. The motion accuracy of the worktable is that it can perform multiple cuts along the repeated offset trajectory, which is the guarantee for improving the machining accuracy of precision mechanical parts and improving the surface quality. The electrode wire has a certain rigidity. After passing through the positioning guide wheel, it actually appears in an arc shape. It has a deviation from the common tangent of the upper and lower guide wheels. The deviation will change with the change of the electrode wire tension.

During the actual processing of precision mechanical parts, since the tension of the electrode wire is in an unstable state, the wire feeding system must control the tension of the electrode wire. At the same time, when the electrode wire is positioned by the guide wheel, due to the semi-open positioning method of the guide wheel, the electrode wire is subjected to the action of the discharge explosion force during cutting, resulting in a difference in the positioning state of the electrode wire in all directions. Therefore, in order to ensure the electrode wire For the stability of the spatial position of the wire during the processing, an electrode wire guide must be added to the wire feeding system. A higher first cutting speed is the premise of the practical use of multiple cuttings. The average cutting speed and surface quality of multiple cuttings are almost the same as the results of the first cutting after reducing the discharge energy, although the machining accuracy of precision mechanical parts can be achieved through multiple cuttings. correction. However, multiple cuts have higher requirements on the quality of equipment and personnel, and the risks are also greater. It is easy to cause wire breakage caused by the increase of discharge energy during the first cut, or the workpiece is scrapped due to the unstable cutting state during multiple cuts. Practice has proved that when the compound working fluid with less oil content is used for cutting, the processing stability, cutting thickness ability, wire breakage rate, surface roughness and other indicators are greatly improved.