The premise of precision EDM
As a precision machining technology, precision EDM must follow an important premise is to use precision machining machine tools. Because when using machine tools for machining, in any case, the machining accuracy will not exceed the accuracy of machine tools. If the accuracy of the machine tool is not enough, the machining accuracy of EDM will be limited, and even the most precise EDM equipment will lose its place. For the EDM of high value-added mold parts, the general discharge machine tool is not competent to complete, and the selection of high-precision EDM machine tool is a very necessary prerequisite. This kind of machine tool has a high degree of automation and outstanding intelligence, which can greatly reduce the dependence of processing quality on human factors.
In addition to meeting the requirements of high-precision EDM in terms of mechanical properties of the structure and various geometric accuracy of the spindle and workbench, this precision machine tool can also obtain extremely high automatic positioning accuracy through the full closed-loop control mode of high-precision grating ruler. The performance of pulse power supply of machine tool directly determines the performance of EDM. In order to achieve higher accuracy, it is required that the discharge gap should be as small as possible. The stable discharge gap depends on the high-speed tool lifting technology, so that the processing waste and tar can be effectively discharged. Under the condition of small gap machining, it can realize stable machining, automatically monitor the state of each discharge pulse, and ensure that the bad pulse does not produce destructive effect.
Precision machining machine tools should adopt high-performance servo control system, so that the machining depth error can be controlled within the minimum limit to meet the requirements of high-precision machining. In finish machining, a variety of shaking methods, such as angular clearance translation, spherical translation, etc., can be used to accurately compensate the size of the profile. The use of waveforms with slope control helps to achieve low electrode loss and process high-grade surfaces.
Requirements for electrodes in precision ignition processing
For the electrodes used in precision EDM, it is necessary to ensure high quality, so precise manufacturing methods should be used to achieve. Generally, the manufacturing of precision electrode is completed by high-speed machining center. After machining, it should meet the requirements that manual processing is not required as much as possible. Even if it is necessary, it is only manual finishing and polishing. This is done to avoid the influence of the subsequent process of the electrode on the accuracy of the electrode, but it also puts forward stricter requirements for the manufacturing process of the electrode.
Electrode material is also a key problem in precision machining. Red copper is the most widely used electrode material in the field of electrical machining, which can meet the requirements of high precision machining. However, in micro machining, in order to reduce electrode loss, reduce the number of electrodes, improve the machining surface quality, and achieve high and stable machining, copper tungsten alloy electrode materials with relatively high prices should be considered.
The size and shape of the electrode shall be measured in detail before being used in EDM, and it can only be used for machining after passing the comprehensive inspection. In actual production and processing, there are many scrapping cases caused by unqualified electrodes. Therefore, it is very important to pay attention to the manufacturing of electrodes in precision machining.