In the hardware processing and manufacturing industry, everyone should be familiar with slow wire processing and fast wire processing. They all refer to EDM machines. What is the difference between these two processing technologies? Let’s take a look at the following:
1. Development status of slow wire processing technology
Multiple cutting technology is the fundamental means to improve the accuracy and surface quality of slow wire processing. Generally, the cutting is performed by one cutting, the secondary cutting is used to improve the precision, and the cutting is performed three times or more to improve the surface quality.
Due to the hysteresis of the wire when cutting the corner, the corner collapses. In order to improve the corner cutting accuracy, more dynamic corner processing strategies have been adopted. Such as: automatically change the processing speed, automatically adjust the water pressure, control the processing energy.
The high-precision finishing circuit adopted by the advanced slow wire processing machine is an effective technique to improve the straightness of the workpiece, which makes the precision of thick parts processing significantly improved; for small rounded corners, narrow slits, narrow grooves and fine parts The micro-finishing, CNC low-speed wire-cut EDM machine can be cut with 0.02 ~ 0.03 mm wire.
In order to ensure high-precision machining, the machine’s mechanical precision, pulse power supply accuracy, servo control accuracy (including control of mechanical motion, pulse parameters, wire routing system and working fluid system) have reached a high level. The water temperature cooling device is used to make the internal temperature of the machine tool the same as the water temperature, which reduces the thermal deformation of the machine tool. The closed-loop digital AC (straight) flow servo control system ensures excellent dynamic performance and high positioning accuracy. The machining accuracy can be controlled in several micrometers. Within the precision positioning, 0.1μm equivalent control can be realized; immersion processing can be used to reduce the thermal deformation of the workpiece; motor servo and closed loop wire tension control; and high-precision tool setting can be realized by voltage modulation tool supply, the tool setting accuracy can reach 0.002 mm Does not damage the workpiece, whether it is wet or dry.
2 Advantages of wire processing technology
Medium-speed Wire Cut Electrical Discharge Machining (MS-WEDM) is a reciprocating high-speed wire-cut EDM machine that achieves multiple cuts on high-speed reciprocating wire EDM machines. Function, commonly known as «medium wire cutting.» The so-called middle wire processing does not mean that the wire speed is between high speed and low speed, but a composite wire cutting machine. That is, the wire routing principle is to use high speed (8-12m/s) wire during roughing. Low speed (1-3m/s) wire is used, so the work is relatively stable, the jitter is small, and the error caused by material deformation and molybdenum wire loss is reduced by multiple cutting, so that the processing quality is relatively improved, and the processing quality can be high speed. Between the wire machine and the low speed wire machine. Therefore, the user said that the «medium wire» is actually a reciprocating wire EDM machine that draws on the processing technology of some low-speed wire-cutting machines and realizes stripless cutting and multiple cutting.
The wire-traveling method uses a low-speed wire-feeding speed limit feed like the second cutting. In the process of machining, the cutting process needs to pay attention to the deformation process. Because the workpiece is cut in the line, it will produce non-directionality due to the influence of the original internal stress and the machining thermal stress generated by the spark discharge. Irregular deformation makes the thickness of the cutting behind the knife uneven, which affects the processing quality and processing accuracy. Therefore, different machining allowances should be reserved according to different materials, so that the workpiece can fully release internal stress and complete torsional deformation, and there can be sufficient margin for finishing cutting in multiple subsequent cuttings, so that the subsequent dimensions of the workpiece can be ensured.
3 advantages of fast wire processing technology
As the name implies, the fast wire processing is named because the wire is used for high-speed wire running during the cutting process. The fast wire processing machine tool is China’s original electric processing machine tool. After decades of continuous improvement and development, it has become an important processing method in the manufacturing industry. It can meet the requirements of medium and low-grade mold processing and other complex parts manufacturing, and has a considerable weight in the middle and low-end market.
At present, the technical index of the fast wire processing machine tool: the efficiency of one cutting is 180mm2/min, the surface roughness after multiple cutting is Ra≤1.0μm, the average efficiency at this time is 50mm2/min, and the surface gloss is not processed. Obviously cut stripe, processing accuracy 0.01mm, electrode wire loss ≤0. 01 mm /200,000 mm2. These performance indicators seem to have been relatively good, but it should be noted that obtaining these indicators requires ensuring good links. Once there are discrepancies, such as the concentration of the working fluid and the loss of the wire, the stability of the processing quality will be affected.
Due to the strong demand for diversification of products in the society, the proportion of multi-variety, small- and medium-sized batch production has increased significantly. It is difficult to adapt to high-efficiency, high-quality and diversified processing requirements using traditional ordinary processing equipment. Silk processing has the characteristics of simple structure, low cost and low consumption, so it also has room for survival. Compared with the fast wire processing machine, the slow wire processing machine has obvious advantages in terms of processing efficiency, precision and surface quality. Although the price of the slow wire processing machine is relatively expensive, with the rapid development of the manufacturing industry, it will be more and more applied to various processing fields.