Fluidized bed for Nylon powder coating

Nylon coating has high hardness, excellent wear resistance, good chemical and solvent resistance, good weather resistance, strong adhesion, good resistance to seawater and salt spray, and excellent comprehensive performance.

Fluidized bed coating is the most common method used for nylon powder coating. The nylon powder is packed in a container separated by a fluidized plate in the middle. Below the fluidized plate is a sealed air rectification chamber, where compressed air with a pressure of about 0.4ky enters the rectification chamber and evenly passes through the micropores of the fluidized plate, causing the nylon powder to suspend, similar to the fluidization phenomenon of liquid convection. Therefore, it is called a fluidized bed. Immerse the coated material preheated to a temperature above 240 into the suspended nylon powder, allowing the powder to melt and adhere to the coated material. After removal, level it naturally or place it again in the baking oven for leveling. The thickness of the coating is mainly determined by factors such as the preheating temperature, specific heat, and immersion time of the coated object. The preheating temperature has the most significant impact on the coating thickness. thicker objects have lower temperatures, while smaller workpieces have higher temperatures. However, it should be as low as 330 ℃ lower than the thermal decomposition temperature of nylon powder. Otherwise, the coating is prone to yellowing and discoloration, becoming brittle, and reducing adhesion to the substrate. For workpieces that are difficult to cool down, water cooling is also required. The immersion coating time is usually greater than 5 seconds and less than 10 seconds. To ensure uniformity, it is recommended to use 2-3 rapid immersion coatings on thicker workpieces. When taking them out, try to use tapping and shaking to remove surface floating powder, which is easier to obtain a uniform coating film.

Usually, the fluidized bed immersion coating method is easy to obtain thicker coatings, and a single coating can obtain a thick film of 250-500 microns. The thickness uniformity of the coating is not as good as cold spraying, but it has high production efficiency, less powder waste, and less equipment investment.

Fluidized bed coating is one of the most common construction processes, with powder particle sizes typically ranging from 50 to 120 μ Between m, suitable for thickness requirements between 250-500 μ The coating of metal parts with m can achieve thicker coating thickness compared to the spraying process, with simple equipment and less investment. This process has high construction efficiency, uniform thickness, and almost no waste of powder. Usually, the workpiece is preheated to 260-350 ° C or even higher, and the immersion time is between 5-10 seconds. The coating thickness can be adjusted according to the workpiece heating temperature and immersion time. To ensure the appearance quality of the coating, 1-3 immersion times can be selected; In some application areas, higher coating adhesion is required, and a matching nylon coating special primer 7P-0200 can be pre coated, such as in harsh areas such as automotive transmission shaft spline coating.