A key step in automotive paint spraying

First of all, it is necessary to carry out pre-treatment, before spraying aluminum alloy profiles and plates, the surface of the workpiece should be degreased, decontaminated and chemically treated to produce a chromized film, increase the adhesion between the coating and the metal surface and the anti-oxidation ability, which is conducive to prolonging the service life of the paint film.

Pigment spraying: It is usually divided into three coats. The first pass is spraying, the purpose of which is to make the paint adhere to the primer coating film; The second spraying covers the red and gray layer of paint or putty in the middle to show the color, pay attention to prevent color spots and flowers; The third coat is used to correct the uneven stains produced by the second coat. The goal is to make the patched area or the entire vehicle color coverage uniform.

Overprint varnish spraying: flash dry for 5 to 15 minutes after the base coat is sprayed, and the solvent is partially evaporated. The first spraying is mainly fog spraying, which cannot be too thick; The second spraying pays attention to the decorative effect, requires flatness and gloss, and adopts the double-pass spraying method.

Paint ratio: different types of paint have different ratio requirements, for example, the ratio of metallic paint and pearl paint is lacquer: thinner 1:1, no reinforcing agent; The ratio of varnish (bright oil) is varnish: hardener: thinner 2:1:0.2-0.5.

Coating process: including cleaning the shell, phosphating treatment, electrophoresis primer, coating sealing glue, spraying topcoat and other steps. Different models, such as cars and buses, have different coating processes.

Technical details: In the process of car paint spraying, special attention needs to be paid to the steps of dealing with foreign objects on the car paint, washing the car, checking the car paint, using sandpaper of different thicknesses for sanding, polishing, reduction and beauty products.

Adjusting and holding the gun: Before spraying, make sure the spray gun is clean and in working order, and check if the spray shape is ideal. When holding the gun, the spray gun should be kept perpendicular to the surface of the workpiece, and the distance should be generally 15-30cm, and the distance should be adjusted as needed to obtain a coating with different effects.

Gun skills: The spray gun and the surface of the coated object should be kept at right angles and run in parallel, and the moving speed should generally be between 30-60cm/s and kept constant to obtain a uniform thickness of the paint film.

Touch-up: Touch-up is recommended to go to a professional repair shop or repair shop, because the baking temperature of the refinish paint is low, and the color needs to be blended on-site to match the original car paint. When touch-ups, larger areas may be repainted to reduce color differences.

Safety and health: When working in a painting environment, you need to pay attention to protective measures, because spray paint may contain harmful chemicals to the human body, such as benzene and its compounds, and long-term exposure may cause health effects.

The basic components of automotive paint: mainly including resins, pigments, additives, fillers, curing agents and solvents. Different types of automotive paints, such as metallic paints and pearlescent paints, also add special ingredients such as glitter gold powder or mica grains.

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