How to improve the machining accuracy of CNC plasma cutting machine?

CNC plasma cutting machine is an important application classification of thermal cutting processing. Plasma arc cutting uses the heat of high temperature plasma arc to partially melt (and evaporate) the metal part at the incision of the workpiece, and uses the momentum of high-speed plasma to remove molten metal to form a cut. a processing method. It has a good performance in cutting efficiency and cutting accuracy, but according to the current operation of most domestic manufacturers, there are often "positive grooves, reverse grooves, saw teeth, and insufficient diagonal accuracy" during the operation. "And other bad sites, thus affecting the quality of the product, failing to meet the requirements of the production process, resulting in waste and increased costs. How to improve the accuracy of plasma processing?

1. The matching of cutting speed and working air pressure.

The CNC plasma cutting machine uses plasma arc for cutting. Compared with oxygen cutting, it has certain defects, which are mainly reflected in the large inclination of the cutting surface, and the finish is not as good as oxygen cutting. The main criteria for evaluating the quality of CNC plasma cutting are: the inclination of the cutting surface, the depth of the cutting line, and the amount of slag.

The height of the cutting tip refers to the distance from the end face of the cutting tip to the surface of the workpiece being cut. The distance is generally 6~8mm. It is the same as the retraction of the electrode, and the distance must be appropriate to give full play to the cutting efficiency of the plasma arc, otherwise the cutting efficiency and cutting quality will be reduced or the cutting nozzle will be burned out. If there are burn marks on the surface of the electrode nozzle, it means that the electrode nozzle can no longer be used and needs to be replaced in time.

2. No-load voltage and arc column voltage

The plasma cutting power supply must have a high enough no-load voltage to easily start the arc and make the plasma arc burn stably. The no-load voltage is generally 120-600V, and the arc column voltage is generally half of the no-load voltage. Increasing the arc column voltage can significantly increase the power of the plasma arc, thereby increasing the cutting speed and thickness of the metal sheet. The arc column voltage is often not reached by adjusting the gas flow and increasing the retraction of the electrode, but the arc column voltage cannot exceed 65% of the no-load voltage, otherwise the plasma arc will be unstable.

3. cutting current

Increasing the cutting current can also increase the power of the plasma arc, but it will be limited by the allowable current range, otherwise the plasma arc column will become thicker, the slit width will increase, and the electrode life will be reduced.

4. Gas flow

Increasing the gas flow can not only increase the arc column voltage, but also enhance the compression effect on the arc column, so that the plasma arc energy is more concentrated and the jetting force is stronger, so the cutting speed can be increased. However, if the gas flow is too large, the arc column will be shortened, the heat loss will increase, and the cutting ability will be weakened until the cutting process cannot be carried out normally.

5. Electrode retraction

The so-called retraction refers to the distance from the electrode to the end face of the cutting nozzle. A suitable distance can make the arc well compressed in the cutting nozzle and obtain a plasma arc with concentrated energy and high temperature for effective cutting. If the distance is too large or too small, the electrode will be seriously burned, the cutting tip will be burned out and the cutting ability will be reduced. The amount of shrinkage is generally 8-11mm.

6. cutting speed

The above factors directly affect the compression effect of the plasma arc, that is, the temperature and energy density of the plasma arc, and the high temperature and high energy of the plasma arc determine the cutting speed, so the above factors are related to the cutting speed. On the premise of ensuring the cutting quality, the cutting speed should be increased as much as possible. Stepping increases productivity and reduces part deformation and heat-affected zone in the kerf area. If the cutting speed is not suitable, the effect will be opposite, and it will increase the slag and reduce the cutting quality.

CNC plasma cutting machine is a kind of advanced mechatronics equipment for cutting metal sheet, which has been widely used in shipbuilding, machinery manufacturing and other industries. There are many factors that affect the cutting quality of CNC plasma cutting machine. In addition to the above, there may be other reasons. Let us continue to explore job hunting and improve the machining accuracy of CNC plasma cutting machine, so that the majority of enterprises can improve product technology and quality, reduce costs and The waste of labor has made my country's CNC plasma equipment continue to develop and reach a higher level.