1. What is the middle wire cutting
Medium-speed Wire Cut Electrical Discharge Machining (MS-WEDM), which belongs to the category of reciprocating high-speed wire-cut EDM wire-cutting machine tools, is used to achieve multiple cutting functions on high-speed reciprocating wire-cut EDM wire-cutting machines , Commonly known as "Medium wire cutting". The medium wire technology points out here that the so-called "medium wire" does not mean that the wire speed is between high and low speeds, but a composite wire cutting machine, that is, the principle of wire travel is to use high speed (8-12m / s) wire feeding, low-speed (1-3m / s) wire feeding is used during finishing, so that the work is relatively stable and the jitter is small, and the error caused by material deformation and molybdenum wire loss is reduced through multiple cutting, so that the processing quality is also Relatively improved, the processing quality can be between the high speed wire drawing machine and the low speed wire drawing machine. Therefore, it can be said that the "medium wire feeding" mentioned by the user is actually a reciprocating wire electric discharge wire cutting machine that borrows from the processing technology of some low-speed wire drawing machines and realizes streak-free cutting and multiple cutting. The middle wire technology has been obtained in practice. The first cutting task in multiple cuttings is mainly high-speed and stable cutting. High peak current can be selected and high current cutting can be performed with a longer pulse width to obtain higher cutting. speed. The task of the second cutting is finishing, which guarantees the accuracy of the machining dimensions. The medium gauge can be selected to make the roughness Ra after the second cutting between 1.4 and 1.7 μm. In order to achieve the purpose of trimming, a low-speed wire feeding method is usually adopted, with a wire feeding speed of 1 to 3 m / s, and the tracking feed speed is limited to a certain range, so as to eliminate the round-trip cutting stripes and obtain the required processing dimensional accuracy . The task of the third, fourth or more cutting (currently medium wire control software can achieve a maximum of seven cuttings) is to polish and polish, and the smallest pulse width (currently the smallest frequency can be divided to 1 μs) for polishing However, the peak current varies with the quality of the surface to be processed. In fact, the finishing process is an EDM grinding with a small amount of machining and does not change the size of the workpiece. The wire feeding method can use the low-speed wire feed speed limiting feed like the second cutting. During the processing of the middle wire walking technology, it is necessary to pay attention to the deformation treatment for multiple cutting. Because the workpiece is cut online, the original internal stress and the effect of the thermal stress caused by spark discharge will cause non-oriented, The irregular deformation makes the cutting thickness uneven in the subsequent cutting, which affects the processing quality and accuracy. Therefore, different machining allowances need to be reserved according to different materials, so that the workpiece can fully release the internal stress and complete torsional deformation. In the subsequent multiple cuttings, sufficient margin can be used for fine cutting processing, so that the final size of the workpiece can be guaranteed.
The middle wire is also a type of wire electric discharge machine tool. The working principle is to use continuous moving molybdenum wire (called electrode wire) as an electrode to perform pulse spark discharge on the workpiece to remove metal and cut. Its wire speed and workpiece quality are between fast wire and slow wire, so it is called medium wire. To be precise: medium wire is an upgraded product of fast wire, so it can also be called: fast wire that can cut multiple times. Therefore, its processing speed is close to fast-feeding, and the quality of processing tends to slow-feeding. The wire speed is between 1 ~ 12m / s, which can be adjusted as required. With multiple cutting functions (same working principle as slow wire cutting), during processing, the control system will automatically adjust the processing parameters (high-frequency pulse width, pulse interval, number of power tubes and wire speed) according to the programmed program. In addition, during processing, the processing parameters can also be changed manually and adjusted appropriately. In the medium wire, on the basis of retaining the characteristics of fast wire cutting machine with simple structure, low cost, good process effect, and low consumption in the process, the advanced concept of precision die processing equipment and slow wire multiple cutting technology (i.e. The first cutting uses a large electrical gauge for high-speed rough cutting, and then uses the fine gauge and fine gauge for the second, third, and even fourth or fifth cuts. The processed surface is polished step by step to To obtain better surface quality and accuracy), this machine is more user-friendly, convenient, and more applicable than wire walking, not only the speed of electrode wire is between "high speed" and "low speed", but also high processing quality In "high-speed wire feeder", and approaching low-speed wire feeder. Therefore, wire walking has brought a revolution to the mold industry, greatly improving the weakness of the original poor quality of wire walking processing, and greatly reducing the cost of mold manufacturing! Medium wire-the price of fast wire, the quality of slow wire!