Sheet metal painting is a kind of automobile repair technology, which is to repair the deformed parts of automobile metal shell. For example, the car body shell was hit by a hole, which can be restored to original shape by sheet metal, and then sprayed with special paint to restore the deformed metal surface to the original, shining as before. The basic process of automobile sheet metal painting is usually divided into four steps: sheet metal correction and sheet metal correction for automobile sheet metal spray painting
I. preliminary plastic work
As everyone knows, how can distort the body against luster paint? It is plain, that is, the deformation of the parts to restore, including body shell, chassis, beams and so on. The sheet metal correction has been developed from the original "smashing, welding, pulling and mending" into the two assembly of the body. Maintenance personnel should not only understand the technical parameters and dimensions of the body, the body must grasp the material characteristics, characteristics of the force transfer body deformation trend and stress point and the production process of the body. Such as welding process and so on. Based on mastering this knowledge, maintenance personnel must use advanced measurement tools, through accurate 3D measurement of body, the indirect damage deformation judgment body directly, make the body repair plan complete, with the body repair scheme is correct, the car body will be restored to the original location of each key point. 　
Two, shaving stereotypes
Automobile body through the sheet metal after correction and some irreparable defects, even the replacement of the components may have not perfect place, in order to be more perfect friends, we must make up for the defects with the techniques of sculpture, car damage deformation and other reasons, the roughness, wheel angle and line. Each place need to fill out the ash scraping remodeling. Scraping = restoring body skin = die product = mold processing procedure. Any body of the car's skin is stamped by the mold, and the repair of the body's skin will be the same as the repair of the mold, so we scrape the gray molding process and mold processing coherent. A lot of dry years painter will sigh a word, "spray a car easy, do a piece of ash difficult, ten years difficult to grinding a group of ash", say this person may really know what the car spraying.
Three 、 automobile sheet metal painting
Automotive sheet metal paint is usually divided into 2 steps:
In primer coating is very important, for a complete smooth working surface finish, the last step to complete all primer work, increase in layer adhesion and have isolation effect, to ensure the quality stability of paint.
Topcoat: topcoat consists of single and multi-layer paint paint, decorative layer and protective layer is to determine the color of the paint, the monolayer is called plain paint, also known as ordinary paint, can be a complete. Paint and paint series multilayer silver and pearl powder paint series, divided into double and multilayer construction process of paint, silver paint is composed of special aluminum material by research into high protection and outdoor stability and strong observability, pearl series paint is composed of mica plate and shell and other materials. By advanced extraction of colorful senior paint highly decorative.
The quality requirements of spraying finish part is very high, should be clean, bright, plump, do not hang, do not hang, shiny uniform, no leakage, no sleight of hand, spray leveling, bite the end, not impetuous, not partial color, all done in place, it's not easy, need technician experience and fault pre discharge capacity. 　
Four, sheet metal painting, paint treatment
In fact, more satisfactory spraying paint is not very perfect, always leave flaws, then only the remediation, such as Benz, BMW will have a fine paint loading phenomenon slightly scaly, we called the "orange peel phenomenon". 　
"Orange peel" is a natural phenomenon in the film drying time leveling process produced, of course people are difficult to detect, to find that the expert level of appreciation ability, so to finish processing, we called the "mirror". 　
First with No. 1500-2000 sandpaper flattening grinding, it is necessary to use No. 2500, then made of wax or clay are components of pumice grinding, dispose of sanding mark. 　
With fine grinding wax next (excluding silicon), dispose of crude wax traces, and then treated with a reducing agent, to achieve the perfect gloss, and surface treatment agent completely remove the aura and wipe marks, then paint to achieve the most deep luster, the last step is to seal, so that you can experts to perfect paint effect.