EDM wire-cutting machine is used for accurate execution of holes in metals of various densities. The movement of the tool occurs with high accuracy and smoothness. Engines for it are produced at the enterprise - the manufacturer of machine tools - using a unique technology.
Design
EDM wire-cutting machine is equipped with plane-parallel engines. To do this, manufacturers create their own neodymium magnets (NdFeB - neodymium-iron-boron). In addition to them, a unique K-SMS control system was required.
The classic EDM wire-cutting machine can process only electrically conductive workpieces. Metals are burned by an arc to a considerable depth. A smooth surface remains in place of the cut, often not requiring additional processing.
EDM wire-cutting machine helps to obtain complex products: molds, strains, conical and cylindrical surfaces, protrusions and bevels. On sale you can find two-axis assemblies used for simple operations. More complex products are obtained using five-coordinate machines.
Principle of operation
In the process of using a wire-cutting machine, brass wire is most often used as a cutting tool. It will be performed using a unique technology, and the speed and accuracy of processing depends on its quality.
If a high-frequency pulse generator of increased power is used, which is built into the described machine, the brass wire is equipped with a special coating. Its structure has several layers:
- Base - CuZn40 (copper-zinc alloy) or brass. Molybdenum, copper can also be used.
- Thermal diffusion layer - zinc concentration of more than 50%.
- The top layer is pure zinc.
Due to this structure, the wire has several advantages:
- Withstands high temperatures.
- The arc during the processing is stable, excluding the formation of sagging at the site of the cut.
- Reduced wire consumption per cut length.
CNC wire EDM machines are mainly used in mass production. Single products do not justify the purchase of expensive equipment, but some details can be obtained only with this type of cut. Zinc coating ensures the continuity of the automatic process by eliminating the shedding of brass from high-frequency currents.
Processing process
Electroerosive processing of materials is based on the formation of a spark due to the passage of high-frequency current through a minimum air or water gap. Most actively, this process occurs with the participation of brass.
There are several types of metal processing on the above equipment:
- Copy and firmware technologies.
- Profile-cut.
- Firmware.
More often, wire for EDM machines is mounted on a movable unit. The blank is placed on a fixed table. The cutting process is controlled by the controller of the CNC system, which simultaneously controls several axes.
The essence of technology
An electrical discharge between the wire and the workpiece removes part of the metal. The selected particles are discharged into the volume of the working fluid. Sludge (crystallizing particles) is filtered and removed at the end of the cut. Processing speed is regulated by current. But the optimal modes should be selected in which no sagging during the cutting process is formed.
Electroerosion helps to manufacture products with very thin walls, process soft metals without mechanical damage. This cutting method is used for flashing to a greater depth. The wire thickness is minimal, only the diameter of the resulting holes is limited by this parameter.
Additional processing is not required, since after cutting with current pulses no burrs remain. Also, an expensive tool used with classical milling methods is not required. This becomes relevant when working with viscous materials.
Hardware Parameters
CNC-control of the process expands the possibilities of metal machining by electrical discharge. Deviations of perpendicularities and rectilinear movements of the axes are not more than 0.01 microns.
Mechanical accuracy is declared by manufacturers, and no additional adjustments are required. The machine is completely ready to start the automatic cycle, it is enough just to load the part model in the standard code.
Modern electronics provide accuracy of movement due to angular and linear sensors, the resolution of which is equal to 1.5 microns. The accuracy of the resulting contours varies from ± 1.5 to ± 5 μm over a length of 300 mm.
Characteristics are selected individually for the needs of production. Based on this, the cost of equipment is formed, oriented to a suitable model.
Additional options
The buyer of the machine with electroerosion can retrofit the equipment with the options presented:
- The controlled position of the axis C. More often required for milling cylindrical workpieces.
- Turret with additional degrees of freedom of the tool. Using this model, geometrically complex parts are obtained.
- The table may have additional axes. This option is used when processing cabinet products or several blanks in one cycle.
The standard equipment includes a system for cleaning the working fluid, allowing filtering with quality up to 3 microns. Contaminated cartridges have standard sizes and change quite quickly.