news
news
2021.6.29
Sandblasting is a kind of workpiece surface treatment process. Compressed air is used as the power to form a high-speed jet beam to spray the sprayed materials (copper ore, quartz sand, emery, iron sand, sea sand) to the surface of the workpiece to be treated at high speed, to change the appearance or shape of the workpiece surface. The sandblasting process was developed by Benjamin tilghman at the end of the 19th century. He built a machine in 1870 to easily peel rust and paint from the surface of the workpiece. Today, we are going to tell you the difference between shot blasting, sand blasting and shot peening.
The principle of shot blasting is to use the motor to drive the impeller body to rotate (directly driven or driven by V-belt), and by the action of centrifugal force, the shot with a diameter of about 0.2 ~ 3.0 (including cast steel shot, steel wire cut shot, stainless steel shot, etc.) is thrown to the surface of the workpiece, so that the surface of the workpiece reaches a certain roughness, and the workpiece becomes beautiful, or the welding tensile stress of the workpiece is changed to compressive stress, improve the service life of the workpiece. By improving the surface roughness of the workpiece, the film adhesion of subsequent painting is also improved. The implication is that shot blasting can be the preceding process of painting process.
Sand blasting uses compressed air as the power to form a high-speed jet beam to spray the sprayed materials (copper ore, quartz sand, emery, iron sand, Hainan sand) to the surface of the workpiece to be treated at a high speed, to change the appearance or shape of the outer surface of the workpiece, It can make the surface of the workpiece get a certain degree of cleanliness and different roughness, and improve the mechanical properties of the surface of the workpiece. Therefore, it improves the fatigue resistance of the workpiece, increases the adhesion between it and the coating, extends the durability of the coating, and is also conducive to the leveling and decoration of the coating.
Compared with other cleaning processes (such as pickling and tool cleaning), sandblasting process has the following characteristics:
1.Sandblasting is the most thorough, universal, rapid and efficient cleaning method.
2.Sandblasting can be selected between different roughness, but other processes can not achieve this. Manual grinding can make rough surface, but the speed is too slow. Chemical solvent cleaning can make the surface too smooth, which is not conducive to coating adhesion.
The surface treatment by shot peening has great striking force and obvious cleaning effect. However, shot peening is easy to deform the sheet workpiece, and the metal substrate is deformed when the steel shot hits the surface of the workpiece (no matter shot blasting or shot peening). Because Fe3O4 and Fe2O3 have no plasticity, they peel off after crushing, and the oil film deforms together with the substrate, so for the workpiece with oil contamination, shot blasting and shot peening can not completely remove the oil contamination. Among the existing surface treatment methods, the best cleaning effect is sand blasting. Sandblasting is suitable for cleaning the surface of workpiece with high requirements. However, the current general sand blasting equipment in our country is mainly composed of hinge, scraper, bucket elevator and other original heavy sand conveying machinery.
1. The cleaning is flexible. It is easy to clean the inner and outer surfaces of complex workpieces and the inner walls of pipe fittings; And it is not limited by the site, it can be moved to the vicinity of large workpieces for cleaning.
2. The equipment structure is simple, the investment of the whole machine is less, the wearing parts are less, and the maintenance cost is low.
3. Large energy consumption, must be equipped with high-power air compressor station
4. Cleaning surface is easy to have moisture, easy to embroider.
5. The cleaning efficiency is low, there are many operators, and the labor intensity is high.
1. Poor flexibility. Due to the limitation of the site, there is some blindness in cleaning the workpiece, and it is easy to produce the dead angle that cannot be cleaned on the inner surface of the workpiece
2. There is no need to set up a high-power air compression station,
3. Cleaning the surface is not easy to have moisture, not easy to embroider.
4. The structure of the equipment is relatively complex, and there are many vulnerable parts, especially blades and other parts, with many maintenance hours and high costs.
5. It has the advantages of high cleaning efficiency, low cost, few operators, easy to realize automatic control, and is suitable for mass production.
Shot peening is driven by high pressure wind or compressed air, and shot blasting is usually carried out by high-speed rotating flywheel. Shot blasting efficiency is high, but there will be dead angle, and shot blasting is more flexible, but the power consumption is large. Although the power and method of the two processes are different, they both aim at high-speed impact on the workpiece, and their effects are basically the same. Comparatively speaking, shot peening is more precise and easy to control the precision, but the efficiency is not as high as shot blasting. Shot blasting is more economical and practical for small workpieces with complex shape, and it is easy to control the efficiency and cost. It can control the shot size to control the spraying effect, but there will be dead angle, It is suitable for batch processing of workpieces with single surface. The selection of the two processes mainly depends on the shape of the workpiece and processing efficiency
Shot peening and sand blasting both use high pressure wind or compressed air as power to blow it out at high speed and impact the surface of workpiece to achieve cleaning effect, but the effect is different with different media. After sandblasting, the dirt on the surface of the workpiece is removed, the surface of the workpiece is slightly damaged, and the surface area increases greatly, thus increasing the bonding strength between the workpiece and the coating. After sandblasting, the surface of the workpiece is metallic, but because the surface is rough and the light is refracted, it has no metallic luster and is dark. After shot peening, the dirt on the surface of the workpiece is removed, the surface of the workpiece is not damaged, and the surface area is increased. Because the surface of the workpiece is not damaged in the process of processing, the excess energy generated during processing will lead to the surface strengthening of the workpiece matrix. After shot peening, the surface of the workpiece is also the natural color of the metal, but because the surface is a spherical surface, part of the light is refracted, so the workpiece processing is sub light effect