Coating is the core part of the production line. The main equipment includes roller coater and drying channel. Generally, the front or back coating process is adopted. According to the different direction of coating roller and transmission roller, it
can be divided into forward coating and reverse coating processes.
(1) coating equipment roller coating machine is a kind of equipment that uses roller to coat coating on aluminum coil. Shanghai scrap copper is widely used in kdwa6td two roller machine and three roller machine. The double roller machine is mainly composed of paint tank, lifting roller, coating roller and transmission roller. During operation, the paint adjusted in advance is pumped into the paint tank by the working pump. The lifting roller is responsible for gluing the paint in the paint tank and transferring it to the coating roller. The coating roller applies the paint to the aluminum coil in the transmission, and the transmission roller is mainly responsible for the transmission of metal coil. In the actual operation process, the relative rotation speed between the lifting roller, coating roller and transmission roller has a certain proportion.
Compared with the two roll machine, the three roll machine has one more control roll. The control roll is used to adjust the amount of paint transferred from the lifting roll to the coating roll, which plays a certain role in accurately controlling the amount of paint. If the rotation speed ratio between the three rollers is unreasonable, the coated material will have surface problems such as horizontal stripes and vertical stripes. Generally, the linear speed of three rollers:
Coating roller speed > transmission roller speed > lifting roller speed. Reasonable control of the rotation speed and proportion of the three rollers is one of the key factors for coating a good appearance film. The three roller machine is mainly used in occasions with high surface requirements.
(2) the coating process is generally pre coated coil aluminum coating process, which can be divided into three coating processes, two coating processes and single coating processes according to the number of coating layers. According to the rotation direction of coating roller and transmission roller, it can be divided into forward coating and reverse coating. If the rotation direction of the coating roller is the same as that of the substrate, the coating method is forward coating. On the contrary, it is reverse coating. Generally, the forward coating process can only paint a low wet film thickness, and the surface appearance of the film coated by this process is not ideal, so this process is not used. Reverse coating process is a widely used coating process at present. By adjusting the rotation ratio between rollers and the travel speed of substrate, the film with required thickness and smooth appearance can be obtained. Coating is the core part of the whole production line. The main parts of this section are as follows:
1. The relative rotation speed ratio between rollers 2, the balance parameter between the thickness and speed of the substrate and the surface temperature of the substrate 3, the viscosity of the coating and the gap between rollers 4, the relationship between the dry film thickness of the coating film and the gap between the coating and the drum 5, the relationship between the curing time, the length of the drying channel, the processing speed of the substrate, the thickness of the substrate and the surface temperature.
(3) post treatment stage the post-treatment section is used to further process the produced coil aluminum to give it better protection and decoration effect. There are mainly film, printing, embossing and molding. In this simple description: the film is to press and paste the polydilute hydrocarbon peelable film on the top coat. Printing is to print various patterns and patterns on the metal roll coated with finish paint. Embossing is the hot embossed pattern on the surface of the paint film. Pressing is to press out a three-dime