What should I pay attention to in the painting line pretreatment system section? During processing, transportation and storage, the surface of the workpiece is often covered with oxidation, rust, grit, weld slag, dust, oil and other dirt. In order to make the deep layer firmly attached to the workpiece surface, the workpiece surface must be cleaned before coating. Otherwise, it will not only affect the bonding force and corrosion resistance of the coating and the base metal, but also make the base metal continue to corrode under the protection of the coating, resulting in the coating flaking off and affecting the mechanical properties and service life of the workpiece. Therefore, surface treatment before the workpiece is painted is an important guarantee and measure to obtain a protective layer of excellent quality and extend the service life of the product.
In order to provide a good surface of the workpiece, the following points are available before surface treatment.
1. Free of oil and moisture
2. Free of rust and oxides
3. No adhesive impurities
4. No acid, alkali and other residues
5. The surface of the workpiece has a certain degree of roughness.
Common surface treatment methods include.
Dip Tank Pretreatment Chemical treatment: Mainly using acidic or alkaline solution to react with oxides and oil on the surface of the workpiece, dissolving it in acidic or alkaline solution to remove rust and oil from the surface of the workpiece. Chemical treatment is suitable for cleaning thin parts, but the disadvantage is that if the time is not properly controlled, the steel will be corroded even if corrosion inhibitors are added. For more complex structural parts and porous parts, residual acid immersed in crevices or holes is difficult to remove completely after pickling with acidic solutions. If not handled properly, it will become a hidden problem for future corrosion of the workpiece, and the chemicals are volatile and costly. Chemical discharge after treatment is difficult. If not treated properly, it will cause serious pollution to the environment. With the improvement of people's environmental awareness, this treatment method is being replaced by mechanical treatment.
Manual treatment: such as scrapers, wire brushes or grinding wheels. The rust and oxide on the surface of the workpiece can be removed by hand, but manual treatment is labor-intensive, low productivity, poor quality and incomplete cleaning.
Spray Pretreatment Mechanical treatment: mainly includes shot blasting and shot peening. Shot blasting is a method that uses centrifugal force to accelerate the projectile and spray it onto the workpiece for rust removal and cleaning. However, blast cleaning is inflexible and limited by the site, resulting in blind cleaning of the workpiece. The inner surface of the workpiece is prone to dead ends that cannot be cleaned. The structure of the equipment is complex, wearable parts, especially the blade and other wearable parts wear fast, long maintenance time, high cost, one-time investment.
Shot blasting is also divided into shot blasting and sand blasting.
With shot blasting, the force of the blow is large, cleaning effect is obvious.
However, the treatment of thin plate workpiece, easy to make the workpiece deformation, and steel shot to the surface of the workpiece (whether shot or shot) so that the metal substrate deformation, such as the lack of plasticity of some workpieces, broken peel, and oil film with the substrate deformation, so the workpiece with oil stains, shot blasting, shot blasting can not The oil contamination can not be completely removed by blasting or shot peening.
Among the existing workpiece surface treatment methods, the best cleaning effect is sandblasting.
Sandblasting is suitable for cleaning workpiece surfaces with high requirements.
At present, most of the general-purpose sandblasting equipment consists of primitive and bulky sand transfer machines such as hinges, scrapers and bucket elevators.
Users need to build a deep pit and waterproof layer to install the machinery, high construction costs, maintenance workload and maintenance costs are very large, sandblasting process produces a large amount of silica dust can not be removed, seriously affecting the health of the operator and pollution of the environment.
With the continuous improvement of science and technology, people's demand for product quality has become higher and higher, and various high-tech equipment has been widely used in enterprises.
With the improvement of people's environmental awareness and the strict requirements of environmental protection departments, it is urgent to control dust pollution and noise environment.
The competition of enterprises is becoming more and more fierce, so how to gain an advantage in the fierce competition, it becomes the key to determine the development of enterprises.
The facts tell us that strict control of production is the prerequisite to ensure the quality of enterprise products, and control of environmental pollution is the responsibility of each of us.