The influence of water jet nozzle on cutting effect
The effect of waterjet processing mainly depends on the processing speed, depth, cutting quality, and straightness of the cutting. So how does the size of the waterjet nozzle affect the cutting effect of the processing? Now analyze it with you。
Normally, the cutting speed and depth of the water jet increase as the nozzle outlet diameter decreases, but when the pressure is constant, the nozzle diameter is reduced, and the jet will be atomized near the nozzle due to air entrainment. , So that it loses cutting ability. The incision depth and incision width of the processed part basically decrease linearly as the nozzle diameter decreases. Under the same pressure, reducing the nozzle diameter will reduce the jet cutting energy consumption ratio. The straightness of the workpiece in the moving direction of the high-pressure jet is independent of the nozzle diameter. By observing the surface quality of the fracture surface of the processed parts of different materials and different process parameters, it is found that the cross-sectional morphology of the processed parts has common characteristics: the upper part of the fracture surface is smoother and the lower part has uneven diagonal stripes, and the jet penetration ability is low. There is an obvious pit area at the bottom of the section. The cut section shape of the processed part is V-shaped, the upper part is large and the lower part is small. When the depth of the cut reaches a certain level, the downstream section width does not change. In addition, the cut angles of copper, aluminum, marble and granite are between 514° and 616° after actual measurement. The cut angles of different materials are slightly different, and the size of the cut angle has nothing to do with the nozzle diameter. The cut width of the workpiece is larger than the jet diameter, and the smaller the diameter, the more obvious this trend.
However, as the nozzle diameter increases (0.1mm to 0.4mm), the cutting depth decreases. The diameter of the nozzle outlet for cutting is recommended to be selected within 0.11~0.3mm. In addition, the factors affecting water jet cutters, although the cutting speed and cutting depth decrease with the increase of the nozzle diameter, the slit width increases, that is, the amount of material damage per unit time increases. Under the same pressure conditions, comparing the cutting quality of materials processed with nozzles with a diameter of 0.1mm and 0.4mm, it is also found that as the nozzle diameter increases, the slit becomes wider, the chip size becomes larger, and the slit quality (roughness) also increases. Significantly worse. The influence of nozzle diameter on cutting quality. The straightness of the specimen in the direction of jet movement has nothing to do with the nozzle diameter, and the size of the cut angle has nothing to do with the nozzle diameter. Under the same pressure, the reduction of nozzle diameter reduces the jet penetrating ability, which reduces the cutting quality. Considering many factors such as energy consumption, saving processed materials, cutting efficiency and equipment investment, the nozzle diameter for ordinary material cutting is better to choose 016～110mm, and it is not suitable for abrasive jet cutting below 012mm. It can be considered that the total energy relationship that the amount of material fragmentation increases with the increase of jet power has not changed. Although the increase in jet pressure and nozzle diameter both increase the jet power, its effects are quite different. The former significantly increases the cutting speed and cutting depth, the latter only increases the amount of material broken, while the cutting speed and cutting depth decrease. However, due to the increase of the nozzle diameter, the contact area of the jet on the processed material increases, which increases 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 work efficiency. However, for jet cleaning, rust removal and layer peeling operations, the cutting depth factor is almost ignored, and the more important factor is the area of the jet. Therefore, when the jet pressure reaches the cleaning requirement, increasing the nozzle diameter will increase the operating speed. More effective.