In the hardware processing and manufacturing industry, slow wire cutting and fast wire cutting both refer to WEDM, so what’s the difference between these two processing technologies? Let’s take a look at the following:
- Development status of low speed wire processing technology
Multiple cutting technology is the fundamental means to improve the machining accuracy and surface quality of slow wire. Generally, it is formed by one cutting, the accuracy is improved by two cutting, and the surface quality is improved by more than three cutting.
Because of the lag of the electrode wire when cutting the corner, the corner will collapse. In order to improve the corner cutting accuracy, more dynamic corner processing strategies are adopted. Such as: automatic change of processing speed, automatic adjustment of water pressure, control of processing energy, etc.
The high precision finishing circuit adopted by the advanced slow moving machine tool is an effective technology to improve the flatness of the workpiece, which significantly improves the accuracy of thick workpiece processing; In order to carry out micro finish machining of small fillet, narrow slot, narrow groove and micro parts, the NC low speed WEDM machine tool can use 0.02 ~ 0.03 mm electrode wire for cutting.
In order to ensure high-precision machining, the mechanical accuracy, pulse power supply accuracy and servo control accuracy of the machine tool (including the control of mechanical motion, pulse parameters, wire feeding system and working fluid system) have reached a very high level. Using water temperature cooling device, the internal temperature of the machine tool is the same as the water temperature, which reduces the thermal deformation of the machine tool; The closed-loop digital AC (DC) servo control system ensures excellent dynamic performance and high positioning accuracy. The machining accuracy can be controlled within several microns, and the precision positioning can achieve 0.1 μ The control of m equivalent; Immersion machining is used to reduce the thermal deformation of the workpiece; Motor servo, closed loop electrode wire tension control; Using voltage modulation tool setting power supply to achieve high-precision tool setting, tool setting accuracy can reach 0.002 mm, no damage to the workpiece, no matter dry or wet.
Advantages of 2-wire processing technology
Medium speed wire cut electrical discharge machining (ms-wedm) belongs to the category of reciprocating high-speed WEDM, which realizes multiple cutting function on high-speed reciprocating WEDM, and is commonly known as “medium speed wire cut”. The so-called middle wire cutting does not mean that the wire cutting speed is between high speed and low speed, but the compound wire cutting machine. That is to say, the wire cutting principle is to adopt high speed (8-12m / s) wire cutting in rough machining and low speed (1-3m / s) wire cutting in finish machining. In this way, the work is relatively stable and the jitter is small, and the error caused by material deformation and molybdenum wire loss can be reduced through multiple cutting, The processing quality can be between high speed wire feeder and low speed wire feeder. Therefore, the user’s “medium wire” is actually a reciprocating WEDM, which uses the processing technology of some low-speed wire cutting machines for reference, and realizes the stripless cutting and multiple cutting.
As for the second cutting, low speed wire feeding and speed limited feeding are adopted. In the process of machining, the deformation treatment should be paid attention to for many times of cutting, because when the workpiece is online cutting, with the effect of the original internal stress and the influence of the processing thermal stress produced by spark discharge, the non directional and irregular deformation will be produced, which makes the cutting depth uneven and affects the processing quality and accuracy. Therefore, it is necessary to reserve different machining allowance according to different materials, so as to fully release the internal stress and complete torsion deformation of the workpiece. In the subsequent multiple cutting, there is enough allowance for finishing machining, so that the later size of the workpiece can be guaranteed.
▌ advantages of fast wire processing technology
As the name suggests, fast wire processing is named for the high speed wire running of electrode wire in the cutting process. Fast moving machine tool is an electric machine tool created by Du in China. After decades of continuous improvement and development, it has become an important processing means in the manufacturing industry. It can meet the requirements of medium and low-grade mold processing and other complex parts manufacturing, and occupies a considerable proportion in the medium and low-grade market.
At present, the technical index of fast cutting machine tool: the efficiency of one cutting is 180 mm ²/ The surface roughness is RA ≤ 1.0 μ m. The average efficiency is 50 mm ²/ The machining precision is 0.01mm, and the loss of electrode wire is less than or equal to 0.01mm/200000 mm ² 。 These performance indicators seem to be quite good, but it should be noted that to obtain these indicators, we need to ensure all aspects. Once there are differences, such as the concentration of working fluid and the loss of electrode wire, the stability of processing quality will be affected.
Due to the stronger social demand for product diversification, the proportion of multi variety, medium and small batch production has increased significantly, and the traditional ordinary processing equipment used in middle walking processing has been difficult to adapt to the requirements of high efficiency, high quality and diversification. However, middle walking processing has the characteristics of simple structure, low cost and low consumption, so it also has its living space. Compared with fast-moving machine tool, slow-moving machine tool has obvious advantages in processing efficiency, precision and surface quality. Although the price of the machine tool is more expensive, with the rapid development of the manufacturing industry, it will be more and more used in various processing fields.
ken. tang@chengcg.com
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