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Large thickness wire cutting usually refers to steel over 200mm, as for other materials with higher electrical conductivity, higher thermal conductivity or high temperature resistance, such as copper, cemented carbide, pure tungsten, pure molybdenum, etc., 70mm thick It has been very difficult. The High-Speed CNC Machine Tool Supplier will analyze the following points.
The main contradictions of large thickness cuts are:
1. Without the entry and exchange of water, the corrosion cannot be removed in the gap, the insulation cannot be recovered, and the discharge cannot be constituted.
2. The stuffing in the gap shunts the energy of the pulse source in a resistive manner, so that the satisfied breakdown voltage and single pulse energy are lost between the wire and the workpiece.
3. The current carrying capacity of the molybdenum wire is limited. It is impossible to have a larger pulse energy transmitted into the gap.
4. The distance between the middle part of the slit of the MS-WEDM machine to discharge the etched material is too long, and the attenuated spark discharge has become an unsatisfactory explosive force and sewage power.
5. For data reasons, the possibility of impurities and internal stress in large thickness is greatly enhanced. The probability of abnormalities and deformation of the slit is also increased. Losing the cutting impact force increases the possibility of being shorted.
Wire Cutting Machine Tool
To deal with the major contradictions of large thickness incisions, the following methods can be adopted:
1. Increase the energy of a single pulse (the voltage, current and pulse width of a single pulse, the product of these three is the energy of a single pulse). Under the premise of increasing the pulse distance, the intention is that the average value of the molybdenum wire current capacity does not increase, the ability to form a spark discharge, and the explosive force of the spark is enhanced.
2. Select a coolant with a higher dielectric constant, a stronger healing insulation, and a stronger fluidity and better drainage capacity.
3. The pulse voltage is greatly improved, so that the discharge gap is enlarged, and the water entering and discharging is relatively simple.
4. Pre-process the material to be cut beforehand. For example, use the repeated forging method to evenly arrange, remove impurities, and anneal and effectively process the internal stress of the material. The stress of the data is fully released by removing the large residuals.
5. Improve the wire speed and smoother wire transport, so that the ability to carry water and resist short circuit can be enhanced.
6. Manually compose the feeding mode of folding line feed or active feed forward and retreat, so that the gap can be expanded effectively.
The erosion material presents the role of resistance load in the gap, it short-circuits part of the energy provided by the molybdenum wire to the gap, so when the cutting material is thickened, the erosion material is more difficult to discharge, the energy loss is much The effective processing pulse will be less, the discharge current becomes a linear load current, and the molybdenum wire is only heated when it is not processed. This is the main reason for energy loss and wire breakage.
Aiming at the two main factors that affect the processing efficiency, corresponding efforts should be made in the following aspects to increase the processing speed: increase the energy of a single pulse, that is, the pulse amplitude and peak current, so as not to overload the current carrying capacity of the wire. , The pulse interval should be increased accordingly, so that the average current does not increase too much. Maintain the dielectric constant and insulation strength of the coolant, maintain high spark explosion force and cleaning ability, and minimize the short-circuit effect of the etched material on the pulse. Improve the mechanical accuracy of the Wire Cutting Machine Tool wire guide system, because narrow seams always go faster than wide seams, and straight seams always go faster than zigzag seams. Properly increase the wire speed, so that the speed of water brought into the gap by the wire is increased, the amount of water is increased, and the ablated material is discharged more effectively.