What are the auxiliary processes in coating process?

With the rapid development of coating industry, more and more attention has been paid to the domestic painting technology and process management, and great progress has been made. If the coating process is generally composed of a plurality of working procedures, the process depends on the coating decorative and functional coatings, for applications requiring high dozens, or even hundreds, but the process content and its essence, the coating process is by pretreatment, paint coating and drying 3 basic processes, and a combination of several auxiliary processes.

Electrostatic coating equipment auxiliary process is not necessary to form a coating process, but to the main process of auxiliary role, or a particular product requirements of the coating process. It includes grinding, polishing, waxing, injecting wax, coating the car bottom, coating, sealing and other processes. Because it is the auxiliary process, so many manufacturers of these processes have not been fully recognized and sufficient attention.

Grinding

Grinding is divided into dry sanding and wet grinding, dry sanding without water wetting, wet grinding is in the grinding coating, while water or other wetting agent lubrication, in order to obtain more smooth surface and wash away the grinding ash. Such as grinding nitrocellulose paint and vinyl chloride paint, not only water wet, but also use loose perfume wet, in order to improve the decorative finish, before polishing, can use very fine water sandpaper polish, also can use soap water as wetting agent. The main purpose of grinding is to:

1, remove the surface of the substrate burr and sundry, such as floating rust, etc.;

2, to eliminate the coating surface of the particles, roughness and roughness, such as surface scratch putty after drying and the general surface roughness, surface by grinding to obtain a smooth;

3, enhance the adhesion of coating. The adhesion of the coating on the smooth surface is poor, and the mechanical adhesion of the coating can be enhanced after grinding. Therefore, grinding is one of the important operations to improve the coating effect.

Polished surface with coarse or fine sandpaper emery cloth, etc.. Putty grinding generally fill the pit with fine sand or stone. Emery cloth sandpaper and only suitable for dry grinding. In wet sanding, water resistant abrasive paper (water, sand paper) is applied to the coating and finish coat. According to the abrasive particle size of water resistance sand paper, there are several numbers. The higher the number, the smaller the size of the abrasive particles, the finer the sandpaper.

When grinding, we must pay attention to the main items:

1, should be strictly in accordance with the requirements of process selection of grinding material, dry grinding putty 80# ~ 120# water sandpaper; wet grinding coating with 240# ~ 320# water sandpaper; wet sanding 360#, 400# ~ 600# with finish coating water sandpaper, not residual traces of sandpaper. At the same time, before grinding, should check the quality of water resistant sand paper, should not have mechanical impurities (coarse sand), in order to prevent scratching coating. Water resistant sandpaper to tear, use should be wet with water, and then tear or fold the use;

2, grinding should pay attention to the direction, should not be in all directions indiscriminately grinding, grinding should not press too tight. In order to improve the smoothness of the polished surface, the sandpaper can be padded with softwood or rubber blocks when hand polished. Cork grinding block is suitable for grinding putty in middle application. Rubber block is suitable for middle coat or top coat;

3, in the grinding process should continue to remove grinding dust, wet grinding and finally rinse thoroughly with deionized water, dried, the coating surface drying;

4, the coating should be dry before grinding, or sanding will be sticky sandpaper, thereby affecting the quality of grinding.

Because grinding is generally manual operation, and sometimes with pneumatic tools or some simple equipment, so grinding labor intensity, in the production of water production in the industrial coating is trying to eliminate this work.