The wire-cutting method is used for the hole processing and shape processing of the cavity and template of the plastic mold. The technology of wire cutting is used to replace the electrode with a metal wire for electrical discharge machining.
The wire material generally uses brass (alloy of copper and zinc). In addition, there are cases where tungsten is used.
The diameter of the wire is generally 0.03 to 0.3 mm, and it is used according to the shape accuracy of the workpiece (workpiece). If it is a thin line, the R angle of the corner can be processed to be very small. However, thin wires are easy to break, and tungsten is used in most cases, but the price is high. The choice of the material and thickness of the metal wire has a great influence on the processing accuracy and processing cost.
Discharge pulses are generated tens of thousands to millions of times per minute. By controlling the amount of pulse generated, the processing speed, surface roughness and shape accuracy are controlled. In the case of wire cutting, oil and water are used as the machining fluid. Since oil and water have different insulation resistance values, the machining fluid is selected according to the desired surface accuracy and function. The processing fluid is not used once, but recycled. However, if the water quality maintenance and processing waste filtering device is not equipped, the processing accuracy will be reduced, so be careful.
The wire cut wires are fixed by two guide rails. In addition, the metal wire is supplied from the reel by the feeding device and is disposable. Depending on the fixing accuracy of the metal wire, the section of the processed surface may sometimes bend in a round shape, which is also an important point in the processing conditions.
Wire-cut electrical discharge machining usually adjusts the dimensional accuracy and surface roughness by machining more than two times. Of course, the electrical conditions and processing conditions during each processing must be optimized. In many cases, the processing may be repeated 6 times.
The processing sequence and the guide hole processing of the place removed in the wire cutting processing are also the points to note about the dimensional accuracy. Whether the pre-processing and processing procedures are carefully studied before programming, the quality after processing is greatly affected. Skilled processing technicians have a wealth of experience and technology in this area.