Influence of Wire Transport Mechanism, Machining Accuracy and Guide on the Performance of Wire Cutting Machine Tool

1. The influence of the wire transport mechanism of the wire cutting machine tool on the broken wire

The wire conveying mechanism of the wire cutting machine is mainly composed of a wire storage drum, a wire rack and a guide wheel. When the accuracy of the wire conveying mechanism decreases (mainly the transmission bearing), it will cause the radial runout and axial movement of the wire storage drum.

The radial runout of the wire storage drum will reduce the tension of the electrode wire, causing the wire to become loose, and in severe cases, the molybdenum wire will be pulled out of the guide wheel groove and broken. The axial movement of the wire storage drum will cause uneven wire arrangement, resulting in the phenomenon of wire stacking. The shaft and bearing of the wire storage drum often have gaps due to wear, and it is also easy to cause the wire to vibrate and break the wire. Therefore, the worn shaft and bearing and other parts must be replaced in time. If the high-frequency power supply is not cut off when the wire storage drum is reversed, the molybdenum wire will be overheated in a short time and the molybdenum wire will be blown. Therefore, it is necessary to check whether the travel switch at the rear end of the wire storage drum is out of order. It is necessary to keep the wire storage drum and the guide wheel flexibly rotating, otherwise the wire transport system will vibrate and the wire will be broken during the reciprocating movement.
After winding the wire, run the wire without load to check whether the molybdenum wire is shaking. If there is shaking, analyze the reason. The limit stop at the rear end of the wire storage drum must be adjusted to prevent the wire storage drum from rushing out of the limit stroke and breaking the wire. The stopper in the wire stopper device contacts and rubs against the fast-moving molybdenum wire, which is easy to generate grooves and cause the clamping wire to break, so it needs to be replaced in time.

The wear of the guide wheel bearing will directly affect the accuracy of the guide wire. In addition, when the V-shaped groove of the guide wheel, the gem limit block, and the groove generated by the conductive block are worn, the friction force of the electrode wire will be too large, and it is easy to remove the molybdenum Silk is broken.

This phenomenon generally occurs when the machine tool is used for a long time, the workpiece is thick, and the wire transport mechanism is not easy to clean. Therefore, the precision of the wire-moving mechanism should be regularly checked during the use of the wire-cutting machine tool in the middle, and the easy-to-wear parts should be replaced in time.

2.Second, how to measure the machining accuracy of the wire cutting machine tool

When the user uses the wire-cutting die processing, the wire-cutting process is the final process, so the processing accuracy is very high. If the mechanical precision of the wire-feeding machine tool is not good, it will directly affect the processing quality of the product and the mold. This leads to the loss of users and the loss of the market. Therefore, it is very important to judge and measure the accuracy, structure, and pros and cons of the WEDM machine tool when selecting the type of the WEDM, so let’s briefly explain it;

Generally speaking, it is easy to judge the accuracy of the new wire-cutting wire cutting machine, because there are the national standard GB7926-2005 and related general standards for the accuracy of wire-cutting machine tools, so users can know whether they are qualified or not when they buy a new wire-cutting machine tool for debugging and acceptance; However, the most important thing is to judge the accuracy retention of the wire cutting machine, because the quality of the precision retention of the wire cutting machine can only be reflected when the wire cutting machine is used for a certain period of time, and the national standard cannot It carries out strict quantitative control, so users can only have an in-depth and detailed understanding of the wire cutting machine and its structure when selecting models, and must not hear hearsay or listen to some unfounded rumors, so as not to disturb your judgment. force, affecting your processing time.

3. The main role of the guide in the processing technology of the wire cutting machine tool

It is well known that gem guides are installed in the upper and lower guide nozzles of the slow-moving wire cutting machine, and play a key role in improving the accuracy. Because the wire speed of the wire-feeding machine is very slow, and the wire material is copper, the hardness is low, so the wear of the electrode wire to the guide is small. It is easy to manually (or automatically) pass through the guide.

However, the situation of the wire cutting machine is different. Since the electrode wire is molybdenum wire, its hardness and stress are far greater than that of copper wire. When the molybdenum wire is observed under a microscope, there are a lot of "bubble" on the surface of the molybdenum wire, when the molybdenum wire runs at a high speed, it is like a "wire saw" for the guide. Therefore, compared with the slow wire, the wear of the guide is very large, and it is difficult to coincide the small hole of the guide with the molybdenum wire between the upper and lower capstans when the guide is installed. This not only accelerates the wear of the guide, but also directly affects the spatial position of the molybdenum wire during cutting.
The impact on the positional accuracy of mold processing and the consistent EDM machine accuracy of the same parts is very fatal. In addition, due to the large internal stress of the molybdenum wire, the small hole of the guide can only be 0.01mm larger than the diameter of the molybdenum wire (otherwise there is no guiding effect), and the guide and the molybdenum wire are full of working fluid, so the operator should It is very difficult to pass through this small hole, which is a huge test for the operator's patience. Judging from the actual application situation, most of the customers gave up the application of the guide. It can be seen that the application of the guide is not the key to improving the precision and finish of the wire cutting machine for the wire cutting machine.