Micro concave plate coating
The coating roller is a mesh roller with a diameter generally within Φ 20mm- Φ Between 50mm, it is called micro gravure coating, which is a directional and contact coating method. The rotation direction of the micro coating roller is opposite to the feeding direction of the material film, and the material film is not pressurized by the pressure roller on the coating roller.
The traditional gravure coating method, whether direct or reverse coating, generally includes backpressure rubber rollers and mesh rollers with a diameter roughly the same as the rubber.
Due to the material film being pressed between the rubber roller and the mesh roller, there is a high possibility of defects such as wrinkles and cracks appearing on the coating surface. The contact point between the two rollers during compression is affected by mechanical and pneumatic factors, which can affect the coating quality.
And micro gravure coating is a contact coating, which means there is no back pressure rubber roller. Therefore, some potential adverse factors caused by the back pressure roller pressure are eliminated.
Advantages:
1. A very thin coating can be applied to very thin materials. Due to the absence of back pressure rollers, there are no defects such as offset printing and wrinkles on the coating surface.
2. As there is no back pressure roller, the edges of the material film can also be coated with glue, without worrying about the glue liquid being applied to the back pressure roller and affecting the coating.
3. Due to the light contact between the scraper and the mesh roller, the wear of the scraper and mesh roller is very small.
4. The micro concave roller has a small diameter and light weight, making it convenient to replace with different coating amounts. 5. Reverse coating can achieve a relatively flat coating, with a uniform distribution of coating amount.
Disadvantages:
1. The glue storage tank for micro gravure coating needs to maintain a full state of glue during coating. The micro gravure roller only comes into contact with the overflowing liquid, so it cannot fully utilize the glue in the storage tank and cannot be recycled, resulting in a certain amount of waste. The amount of glue waste is about 10KG.
If the micro concave roller is not cleaned thoroughly after use, it is easy to cause rust on the micro concave roller and it is difficult to remove rust.
3. Due to the exposure of the adhesive solution in the adhesive storage tank to the air during coating, dust and particles in the air during coating are prone to fall into the adhesive storage tank, which can have a certain impact on the quality of coating.
4. The glue supply system for micro gravure coating is relatively complex, and cleaning and dismantling are difficult, often requiring 1-2 hours of time