Treatment of paint accumulation at the bottom of t

Treatment of paint accumulation at the bottom of steel barrel in electrostatic spray painting

our factory has used electrostatic spray painting process for 15 years, and has also carried out two large-scale technical transformations in the middle, and has realized a full-automatic production line. Then, the cleaning equipment before the coating of the steel barrel was reformed, which greatly improved the coating quality of the outer surface of the steel barrel and was well received by users. However, with the increasingly fierce market competition and the continuous improvement of user requirements, the coating quality of steel barrels in our factory has also appeared some problems that can not meet the requirements of users. At the beginning of the year, the user raised the problem of paint accumulation at the bottom of the barrel. Through careful analysis and treatment, we successfully solved this quality problem. The user was very satisfied and said happily: different, just different

I. Analysis of the causes of quality problems

the phenomenon of quality problems is: on the bottom surface of the steel barrel after painting and drying, it can often be found that there are pieces of paint accumulation, which affects the appearance of the outer surface. These paint deposits are at least 32 places, at most more than 10 places, different sizes, and generally present 5-10 mm protruding dots

in order to find out the cause of the problem, we carefully tracked and investigated the process from the painting of the steel barrel to the drying out of the barrel, and found that the paint accumulation problem on the barrel bottom was caused by the following reasons: in the paint booth, the paint mist ejected from the spray tray was constantly adsorbed on the rack and hanger of the guide rail, and after excessive adsorption, it flowed or dropped from the rack and hanger, and the paint dripped on the barrel bottom, After drying, raised paint spots are formed

briefly, our painting method is electrostatic painting, and the steel barrel conveying method is chain suspension conveying. The bottom of the steel barrel is upward and vertically enters the shaped spray chamber for painting. The steel barrel is grasped on the flange of the barrel bottom by the three claw hanger. The rotation of the steel barrel in the spray booth depends on the transmission of the guide rail gear on the hanger and the shaped rack in the spray booth. The spray tray is located in the center of the spray chamber and rotates by pneumatic motor drive. Driven by the cylinder, it moves up and down. The motion stroke is slightly larger than the height of the steel barrel, so that the steel bottom and top are covered with paint

II. Test of methods to solve quality problems

in order to solve the problem of paint accumulation at the bottom of the barrel, we have taken a series of measures to carry out the test. The test methods and results are as follows:

1. In order to solve the problem of paint accumulation and dripping of hangers, we implement the method of regular replacement of two sets of hangers. Because the hanger will absorb paint every time it passes through the paint booth, but it will be cured on the hanger after drying. In the field of new energy vehicles, only when the electronic universal experimental machine on the hanger is mainly used for stretching, tightening, bending, shearing, tearing, peeling, and other industries such as metal wire, metal foil, plastic film, wire and cable, adhesive, wood-based panel, wire and cable, waterproof materials, etc In the mechanical property test of circulation and other methods, the paint can be dripping only when the paint is thick and there is a downflow nozzle. Generally, under normal production conditions, replacing the hanger once can produce about 10000 barrels

2. The accumulated paint on the rack in the paint booth does not dry, so there will be dripping if it is slightly adsorbed. The newly treated rack cannot be sprayed with 200 barrels, that is, there will be dripping of paint. In order to prevent the rack from dripping paint, we must find a way to prevent the paint from adsorbing on the rack. Starting from the purpose of "halbl nder", we first lengthened the length of the hanger, so as to reduce the height of the barrel during painting and reduce the highest point of the spray plate at any time. In this way, the front contact between the paint mist and the rack is avoided and the paint absorption of the rack is reduced, but the effect is not perfect, because there is always flying paint mist absorbed, and the problem of paint dripping has not been completely solved

3. In order to reduce the paint mist flying up to the rack, we set a plastic plate cover at 150mm on the spray plate to reduce the rise of paint mist. After the test, it was found that the paint accumulation on the rack was significantly reduced. 400~500 barrels could be produced before the rack began to drip paint, but it could not make the rack do not drip paint, and the satisfactory effect could not be achieved

4. In order to better reduce the adsorption of paint mist to the rack, we installed a baffle between the rack and the spray tray. The baffle is made of plastic plate and bent into a shape corresponding to the shape of the rack. After the test, although the paint accumulation of the rack is greatly reduced, the paint mist adsorbed by the baffle began to drip after a period of production, which proved that the effect is not ideal

5. Through the above tests, we realize that in order to completely solve the problem of paint accumulation at the bottom of the barrel, it is obviously impossible to make obstacles on the existing equipment to prevent the rise of paint mist. Therefore, we try to change the rotation method of the steel barrel in the paint booth and remove the rack drive structure. We studied and tried the inertia rotation method, that is, when the steel barrel is about to enter the paint booth, we use the electric toggle wheel to rotate the steel barrel. When entering the paint booth, the steel barrel has not stopped rotating against the inertia until it comes out of the paint booth after spraying. This method has a good effect and directly prevents the generation of paint dripping on the rack

III. conclusions and feelings

through a large number of experiments and analysis, we finally found a better solution: adopt the method of regular replacement of two sets of hangers to solve the problem of paint dripping of hangers; The method of inertia rotation of steel barrel is used to replace the rack transmission structure, which solves the problem of paint dripping on the rack

from this minor reform, we realize that to solve problems, sometimes we can't just stay on the existing conditions, don't be afraid of difficulties, and don't have the idea of being perfunctory and dealing with errands when Mongolian congressman bat Qimuge studied Chinese at Beijing Language and Culture University from 1991 to 1995. Think more broadly and dare to break the rules of the current situation. Only in this way can there be more and better ways to solve the problem