Valve coating process and technical information

Electrostatic powder coating, a popular method used in industrial applications to apply a protective and decorative finish to metal surfaces. 

When the powder particles are ejected from the nozzle and pass through the discharge area, they collect a large amount of electrons and become negatively charged particles. Under the action of electrostatic attraction, they are attracted to the positively charged workpiece. When the powder adheres to a certain thickness, the effect of "same repulsion" will occur, and the powder can no longer be adsorbed. After heating and curing, the powder layer will level out and become a uniform film layer.

The typical powder electrostatic spraying (metal) technological process is as follows: upper part → degreasing → cleaning → rust removal → cleaning → phosphating → cleaning → passivation → powder electrostatic spraying → curing → cooling → lower part powder electrostatic spraying (plate) technological process. Powder coating is a kind of coating that contains solid powder and is applied in powder form to form a coating.

It is different from general solvent-based paints and water-based paints. It does not use solvents or water as the dispersion medium, but a new type of paint that uses air as the dispersion medium. Therefore, powder coating and its process equipment is a new process and technology developed in recent years, and electrostatic powder spraying technology is a coating process that is currently developing rapidly in powder coating. The basic principle of electrostatic powder spraying is to form a high-voltage corona discharge electric field between the spray and the workpiece.

In electrostatic spraying factories, the main reasons for poor coating impact performance and low adhesion are: too thick phosphating film; low baking temperature and insufficient powder curing; poor powder quality; expired powder; too thick coating; poor degreasing and rust removal Thoroughly; two powders of different properties are mixed. Solution: coating phosphating parameters such as concentration, temperature, time, etc.; adjust curing conditions; improve powder quality in the powder factory; check the production date of the powder, check the expired powder before it is qualified; measure the film thickness and adjust the spraying parameters; strengthen Pre-treatment; strengthen on-site management.

Precautions for spraying valves

Discharge the gas with higher dust concentration in the spraying area in time, and control the dust concentration below the limit value. Environmental needs: prevent powder from spilling and polluting the environment in other areas. Provide power for powder purification facilities and overcome the resistance of air ducts. We all know that industrial spraying is a big systematic project, in addition to the equipment required in the powder spraying process,It is also necessary to coordinate the operation of spraying pretreatment, conveying and other equipment at the same time to allow the entire system to maintain a steady stream of production products. The oversprayed powder (gravity sedimentation at the bottom of the spray cabinet and recovery of the separated powder) is transported to the spraying powder delivery system to achieve the purpose of reuse. Prolonged exposure of instant overspray powder to open air may cause dust pollution. Reduce the amount of powder in the spray area, facilitate the cleaning efficiency and speed when changing the powder, and reduce labor intensity.

The less powder that stays in the spraying cavity and the recovery cavity, it is beneficial to reduce powder change and color change, reduce dust flying, and improve the working environment. Security needs. Board hanging → preheating conductivity → electrostatic spraying (primer coating) → hot melt curing → cooling → unloading the main factors that affect the quality of powder electrostatic spraying in powder electrostatic spraying.

Electrostatic spraying manufacturers, the powder room wraps the entire spraying process in a relatively closed environment. After calculation and reasonable production and processing, the powder in it will not overflow , will not pollute the environment, and can be recycled and reused. The usual powder room wall materials are PP, PVC and special Apogee, usually the powder supply device consists of a powder bucket (built-in powder for spraying).

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