Precision coating technology

Understand the precision coating process. The traditional precision coating methods, such as blade coating or roller precision coating, are simple and convenient to operate, but can only produce low value products at a unit price of less than 10 yuan per square meter. Moreover, this coating method belongs to an open operation mode, and solvent evaporation affects the health of operators. Environmental protection awareness is becoming increasingly important today, so it is necessary to make appropriate adjustments.

The establishment of precision coating technology, and with the development of various high-performance coatings, can be used for the development of various products, including our food packaging field. In order to pursue high-quality and high-precision coating products, each stage of the production process needs to be completed through high-quality design.
The coating thickness is only set by the perfusion system and does not change with the rheological property of the coating solution or the coating speed. The principle of this type is to pump the self stabilized coating feed into a precision designed extrusion die to form a wide film with uniform thickness, and then apply it on the substrate. As most electronic products are developing in the direction of light, thin, short and small, and the requirements for precision and uniformity of coating products are gradually improving, domestic coating manufacturers have also set off an investment boom in research and development of precision coating related technologies in recent years, among which precision coating is more popular.
Variable speed motor is used to change the flow range; The structural design of the valve is not adopted, which will not block; Strong self suction capacity, high suction and discharge pressure; Stable operation without vibration and noise; The disassembly and maintenance shall be as simple as possible. In addition to the need to avoid contamination by impurities or bubbles during coating transportation, in order to prevent coating processing defects, filtering devices and defoaming mechanisms will be added during coating transportation to ensure coating quality; A pressure gauge or digital pressure gauge is also installed for online monitoring to prevent excessive filter pressure from closing.
The main purpose of die design is how to design the change of the sectional area of the shunt pipe, so that the coating liquid with different rheological properties can produce a uniform coating liquid film under different processing conditions. In general, the mold design should include the geometric distribution of the internal runner, the internal and external adjustment mechanism, the heating device, the geometric design of the die mouth and the mechanical structure. The internal runner design has a greater impact on the uniformity.
According to the shape of the splitter pipe, it can be divided into two types: T-shaped die with fixed section and hanger die with section changing with position. In precision coating engineering, drying process is one of the important steps to determine the quality of coatings. No matter how the drying process or equipment is designed, it has a significant impact on the quality of precision coating products, and its importance is no less than that of coating process.
Heat transfer can be conducted through conduction, convection and radiation. Heat is transferred from the heat source to the object to be heated. Both conduction and convection require a heating medium. Radiation means that heat is directly transferred to the surface of the object to be heated without heating the intermediate medium (such as air), so it is a relatively energy-saving heating method. In the process of heating and drying, heat transfer and mass transfer occur simultaneously. Heat transfer is to increase the temperature of the coating, increase the fluidity of its water or solvent, and evaporation of water or solvent. Mass transfer is to make the internal water or solvent move to the surface to achieve the purpose of evaporation.