Influence of water jet nozzle on cutting effect
The effect of water jet processing mainly depends on the processing speed, depth, cutting quality, and cutting straightness. How does the size of the water jet nozzle affect the cutting effect of processing? Now analyze it with you:
Normally, the cutting speed and depth of the water jet increase with the decrease of the nozzle outlet diameter, but when the nozzle diameter is reduced under a certain pressure, the jet will be atomized near the nozzle due to air entrainment. , so that it loses its cutting ability. The kerf depth and width of the workpiece decrease substantially linearly as the nozzle diameter decreases. Under the same pressure, reducing the nozzle diameter will reduce the cutting energy consumption ratio of the jet. The straightness of the workpiece in the moving direction of the high-pressure jet is independent of the nozzle diameter. By observing the fracture surface quality of the workpieces with different materials and different process parameters after being cut, it is found that the cross-sectional morphology of the workpieces has common characteristics: the upper part of the cross-section is smooth and the lower part has concave and convex oblique stripes; when the jet penetration ability is low There is an obvious pit area at the bottom of the section, the shape of the cut section of the workpiece is V-shaped, the upper part is large and the lower part is small. When the incision depth reaches a certain level, the downstream section width does not change. In addition, the actual measurement shows that the size of the notch angle of copper plate, aluminum plate, marble and granite is between 514° and 616°. The notch angle of different materials is slightly different. The kerf width of the workpiece is larger than the jet diameter, and the smaller the diameter is, the more significant the trend is.
However, as the nozzle diameter increased (from 0.1mm to 0.4mm), the depth of cut decreased. The diameter of the nozzle outlet for cutting is recommended to be within 0.11~0.3mm. In addition, although the cutting speed and cutting depth decrease with the increase of nozzle diameter, the kerf width increases, that is, the amount of material damage per unit time increases. Under the same pressure conditions, comparing the quality of the material slits processed with nozzles with a diameter of 0.1mm and 0.4mm, it is also found that with the increase of the nozzle diameter, the slits become wider, the particle size of the chips becomes larger, and the quality (roughness) of the slits also increases. significantly worse. The effect of nozzle diameter on cutting quality. The straightness of the specimen in the moving direction of the jet has nothing to do with the diameter of the nozzle, and the size of the notch angle has nothing to do with the diameter of the nozzle. Under the same pressure, the reduction of the nozzle diameter reduces the jet penetration ability, thereby reducing the cutting quality. Considering many factors such as energy consumption, saving of processed materials, cutting efficiency and equipment investment, the diameter of the nozzle for ordinary material cutting is preferably 016-110mm, and it is not suitable for abrasive jet cutting below 012mm. It can be considered that the overall energy relationship that the amount of material breakage increases with increasing jet power does not change. Although increases in jet pressure and nozzle diameter both increase jet power, the effects are quite different. The former significantly increases the cutting speed and cutting depth, while the latter only increases the amount of material broken, while the cutting speed and cutting depth decrease. However, due to the increase in the diameter of the nozzle, the contact area of the jet acting on the material to be processed increases, thereby increasing the crushing resistance of the material, resulting in a decrease in cutting speed and cutting depth.
Therefore, when the jet is used for cutting operations, increasing the jet pressure is an effective way to improve the working efficiency. However, in terms of jet cleaning, rust removal and peeling operations, since the cutting depth factor is hardly considered, and the jet action area factor is more important, so when the jet pressure meets the cleaning requirements, increasing the nozzle diameter will increase the operating speed. more effective.