The characteristics and methods of use of spraying and coating equipment

The smaller the resistivity of the spray processing powder, the easier it is for the powder particles to discharge the charge, the less adsorption force is reduced, and the easier it is to fall off. Therefore, the greater the resistivity of the powder, the easier the saturation of the coating to achieve, the general coating volume resistivity in the range of 109 to 1013 s. cm. The distance between the head of the spray gun and the work piece is usually maintained at about 150 to 200mm, the distance, angle and movement rate of the spray gun should be consistent, the initial growth rate of coating thickness is directly related to the amount of powder supply, after spraying for a certain period of time, the growth of film thickness slows down, When the amount of powder is increased, the deposition is reduced, so that the recovery powder is increased, the general powder output is 70 to 120g/min, and the visual powder supply condition is uniformly foggy for .
After spraying the remedial work piece of the coating defect, if there is a defect, the coating is erased from the re-injection or special tools (such as knives) are used while the work part is still hot, and the industrial aluminum profile distributes the powder coating evenly at the coating defect to melt it. If the work piece is cooled, it can be used with the help of .
(1) powder coating can be applied once to obtain a thickness of 100 to 300 m coating, and the use of ordinary coatings need 4 to 8 times the construction, improve construction efficiency, shorten the production cycle.
(2) coatings are solvent-free, do not need to dilute and adjust viscosity, improve working conditions and reduce the risk of fire, conducive to the protection of the environment.
(3) improves the adhesion and tightness of the coating, metal powder, ceramic powder, etc. mixed coating, can improve the mechanical and physical properties of the coating, coating anti-corrosion performance greatly improved.
(4) is highly mechanized and can recycle excessive coatings, reducing coating consumption.
(5) coating equipment complex, high investment costs, coating appearance and leveling is not as good as spray method, some powder coating methods on the shape size of the work piece has requirements. Only applicable to powder coatings, the cost is high.
1. The construction method of powder coating has obtained the construction method of powder coating for industrial applications: flame spray method (melting method), fluidized bed method, electrostation powder spray method, static current bed method, electrostation powder oscillation method, powder electrophoresis coating method, etc.
II, fluidized bed powder coating process fluidized bed process, because the work parts are preheated to the powder melting point above the coating, melting polymer viscosity is reduced, coating adhesion greatly improved, coating insulation and corrosion resistance greatly improved. Insoluble resins such as nylon, polyethylene, polypropylene, etc. can also be used for construction.different powder coating methods compared
(1) work parts cleaning, work parts must be oil removal and rust removal. Immerse the work piece in gasoline or tachloroethylene vapor to remove the oil, remove rust with blasting or blasting, and clean it up.
(2) preheat work, the temperature of preheat should be higher than the melting temperature of the powder coating about 20 degrees C, according to the size of the work piece and the variety and thickness of the coating, the warm-up range is 170 to 220 degrees C.
(3) the part of the masking work piece that does not need to be coated can be protected by a fixture (e.g. silicone rubber), which acts as a dual role in the clamping work and protection.
(4) coating will be the work piece into the fluidized bed, in order to obtain a uniform and continuous coating, the work piece immersion once removed, immediately reverse 180 degrees, to be melted by the coating and then immersed in turn, industrial aluminum profile and immediately reverse 180 degrees. The time of immersion is 1 to 2 seconds.
(5) thermoclysis to make the coating on the work piece better cured into a film, should enter the drying chamber and reheat. The curing temperature and curing time are determined by obtaining the best coating performance and minimizing the construction cycle. For example, the curing temperature of epoxy powder coating is 180 to 190 degrees C, and the curing time is 40 to 50 minutes.
3. The electrostature powder coating process metal work surface coating process electrostature powder coating process can be indicated by the following process: surface treatment →culsion→ work parts preheated →smoulated→ cured→ →quenched water→ defect remediation → clean-up→ inspection→ into storage.process and characteristics of various powder construction methods
(1) pre-treatment of substrate surfaces is the main step affecting the performance and quality of coating film. Industrial aluminum profiles generally include surface cleaning, oil removal, rust removal and other pre-treatment; If the substrate is an aluminum and magnesium casting, chromate treatment is necessary. After treatment, the substrate surface reaches Sa2.5 level, roughness is 20 to 50 m, phosphate when warming 30 to 40 degrees C, in order to speed up the phosphation rate, phosphate do not wash, take natural drying or heating 60 to 80 degrees C drying, the surface obtained iron ions and residual acid will continue to react to all the phosphate film.
(2) masking For areas that do not require coating, the parts that do not need to be coated need to be coated with non-conductive silicone rubber solution or covered with adhesive cloth before the work piece is warmed up.
(3) the work piece is warmed up in order to obtain the coating of the desired thickness, the work piece can be heated at a certain temperature between sprays. The temperature of the workware warm-up should be slightly higher than the plastic melting temperature, the industrial aluminum profile warm-up time depends on the size and thickness of the work piece, generally to the work parts and oven temperature to achieve thermal balance.
(4) spraying, ground the work parts and connect the head of the spray gun to a high-voltage power supply. The choice of powder coating greatly affects the quality of the coating film. The coating efficiency obtained by the spriticality of powder particles is ideal. Small granularity, low density powder coating by gravity less impact and get a higher coating efficiency.
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