The coating process is actually to apply the coating evenly and thinly on the surface of the
stainless steel plate. Now with the improvement of production capacity and the progress of technology, the emergence of new coatings and the improvement of coating quality requirements, the coating process has been greatly developed, and the trend of automation, pollution-free and high efficiency has begun.
It mainly includes the following three types, namely roller coating, curtain coating and powder coating.
1. The roller coating method is more commonly used, and the adaptability to the coating is also very strong. The surface quality of the stainless steel plate after coating is relatively stable, but this method is easy to form a roller print on the surface of the plate.
However, from the perspective of the relative movement direction of the stainless steel strip and the coating roller, there are two main methods of roller coating: smooth coating and reverse coating.
The first is the smooth coating method, which means that the moving direction of the stainless steel strip and the coating roller is the same. It is characterized by being very suitable for low-viscosity coatings, usually used for thin-film coating. The thickness of the coating film obtained after processing is 10-20 μm. The coating speed is usually not more than 100m/min. Since it exceeds 100m/min, reverse roll coating should be used. Compared with the reverse coating method, the wear of the coating roller is relatively small.
The reverse coating method is actually that the movement direction of the stainless steel strip and the coating roller is inconsistent. Its characteristic is that it is suitable for high viscosity coatings, usually used in thick film coating. Of course, in the production process, the different combinations of the rotation directions of the support roll, coating roll, lifting roll and measuring roll also have different effects on the thickness of the paint film of the stainless steel strip.
2. The curtain coating type is also called curtain flow. Its characteristic is that the paint can easily flow out from the gap at the bottom of the container evenly to generate a paint curtain to be applied to the substrate. This method will not produce roll marks, and is mostly used in the surface processing of high-end home appliances, but the coating amount will fluctuate greatly with the change of speed. few.
3. Powder coating type, that is, using high-voltage static electricity to deposit and attach the coating powder to the substrate to achieve coating. The products produced by this method have the highest comprehensive performance, and the process quality is relatively stable, but they also have the disadvantage of being difficult to control, so they have not been applied on a large scale.
In addition, there are some relatively early brush coating methods, dip coating methods, air spray methods and airless spray methods used in special industries, electrophoresis coating methods, etc., but most of the new color coating lines now use roller coating methods.
