What is wire cutting

Basic information:

Wire cutting is the abbreviation of wire cutting, which refers to cutting raw materials (conductive materials) with linear tools (such as metal wires, molybdenum wires, etc.). It belongs to the category of electrical processing. It was discovered by the former Soviet Union couple Lazarenko when they studied the phenomenon and causes of switch contacts being damaged by spark discharge corrosion. The instantaneous high temperature of the electric spark can cause local metal to melt, oxidize and corrode, thus creating and inventing the electric spark processing method. The wire cutting machine was also invented in the former Soviet Union in 1960, and China was the first country to use it in industrial production. At present, most wire cutting machine tools use microcomputer control systems with a high degree of automation.
It is mainly used to process various complex and precise workpieces, such as punches, concave dies, convex and concave dies, fixed plates, unloading plates, etc. of punching dies, forming tools, templates, metal electrodes for EDM processing, various micro-holes, narrow slits, arbitrary curves, etc. It has outstanding advantages such as small processing allowance, high processing accuracy, short production cycle and low manufacturing cost, and has been widely used in production.

Main features

Compared with traditional CNC turning, drilling, CNC milling, etc., wire cutting has its own characteristics:

(1) Directly using 0.03-0.35 mm metal wire as electrode, no specific shape is required, which can save electrode design and automotive component manufacturers do not need to pay for other electrode manufacturing costs (if using EDM technology, automotive component manufacturers also need to pay for the cost of making "copper");

(2) Regardless of the hardness of the workpiece material, as long as it is a conductor or semiconductor material, it can be processed, and the electrode wire loss is small and the processing accuracy is high (so it is often used to process high-hardness plastic moulding parts or precision machining part);

(3) Suitable for processing small batches, complex-shaped parts, single pieces and trial products with short processing cycles, such as sample manufacturing of automotive parts;

(4) In EDM wire cutting, the electrode wire and the workpiece are not in direct contact, and the interaction between the two is very small, so the deformation of the workpiece is small, and the electrode wire and fixture do not need to be too strong;

(5) The working fluid uses a water-based emulsion, which is low in cost and will not cause fire;

(6) It is not suitable for processing large quantities of parts with simple shapes (such as CNC machining rims), nor can it process non-conductive parts (such as plastic injection components).

Classification:

According to the different running speeds of the electrode wire and the different processing quality, EDM wire cutting machines are usually divided into three categories: the first category is the high-speed wire EDM wire cutting machine (WEDM-HS), whose electrode wire moves back and forth at high speed, and the general wire speed is 8-10m/s. The electrode wire can be reused, and the processing speed is relatively high, but the fast wire feeding is easy to cause the electrode wire to shake and pause when reversing, which reduces the processing quality. It is the main machine type produced and used in China, and it is also China's original EDM processing mode (cnc manufacturing china); the second category is the low-speed wire EDM wire cutting machine (WEDM-LS), whose electrode wire moves in a low-speed unidirectional direction, and the general wire feeding speed is less than 0.2m/s. The electrode wire is no longer used after discharge, and it works smoothly and evenly, with little shaking and good processing quality, but the processing speed is relatively low. It is the main machine type produced and used in most countries. The third category is the medium-speed wire EDM wire cutting machine, which should be accurately called "multi-speed wire feeding". It is a Chinese invention. Its principle is to cut the workpiece repeatedly. At the beginning, it uses a faster wire drum speed and a stronger high frequency to cut, just like the current fast wire cutting. The last cut uses a slower wire drum speed and a weaker high frequency current to polish, thereby improving the processing finish. Moreover, after the wire speed is reduced, the vibration of the guide wheel and the bearing is reduced, and the processing accuracy is also improved. In addition, the first cut is cut at the fastest speed, and the subsequent cutting and polishing cutting amount are very small. Therefore, the time of the three cuts is generally faster than the one-cut cut of the fast wire cutting.

"WEDM-LS" will be used to make very precise parts and customized parts with very high tolerance requirements, such as 0.002mm. The surface finish of the precision parts processed by "WEDM-LS" is very good and does not need to be processed again. The surface of the metal parts processed by "WEDM-HS" is a bit like the "sandblasting" process. If the surface finish requirement is high, it needs to be processed again.
In short, "wire cutting" is a commonly used method for "plastic moulding parts" and "precision machining part". Experienced automotive component manufacturers will use it in conjunction with other machining methods to produce a variety of complex precision parts or precision molds.