• Description
Tile display racks for paint operations, the main purpose is to play a protective and decorative role. However, due to different materials, different materials forming process and other factors, the operation process is slightly different.
Under normal circumstances, the stamping or injection molded parts have good surface smoothness, no need for earth-removing and grinding processes, and there are many defects on the surface of the cast-molded parts, and there are many defects such as blowholes, dents, and poor filling, etc. Improve surface smoothness.
The role of various processes
1. Pretreatment
Metal parts and non-metal parts have different pretreatment methods because of different materials.
1.1 Tile display stand before processing metal material
Degreasing Washing Etching Washing Surface Modification Chemical or Electrochemical Treatment Washing Baking
Degreasing is to remove the oily, absorbent layer on the surface of the workpiece. Etching is to remove oxides on the surface of the workpiece.
This process may depend on the surface condition of the workpiece. The surface adjustment can activate the surface molecules of the workpiece and promote the formation of chemical or electrochemical film layers on the surface of the workpiece. . .
The purpose of water washing is to clean the residual liquid on the surface of the workpiece so as not to bring it into the next tank and contaminate the liquid.
Chemical or electrochemical treatment: Chemical or electrochemical reactions generate a uniform protective layer on the surface of the workpiece to increase the corrosion resistance of the steel surface. Different steel materials use different chemical or electrochemical methods.
Under normal circumstances, as a pre-paint treatment, magnesium alloy parts are mostly chemically oxidized or phosphatized; aluminum alloy parts are chemically oxidized or anodized; steel parts are phosphatized.
The purpose of baking is to remove moisture from the surface of the workpiece and allow the surface of the workpiece to dry completely. The quality of the pre-treatment has a great influence on the coating performance, especially the adhesion of the coating. Therefore, pre-treatment is a very critical process before painting.
2. Masking
The purpose is to protect the parts that do not need to be painted.
At present, most of the workpieces use the shielding fixtures, but for the workpieces with complex shapes, some parts can not be achieved by the shading fixtures. Even for the workpieces with simple shapes, large volumes, and fewer shading areas, this process is indispensable.
The selection of the material used for the masking should take into account the baking operation of the subsequent process, that is, the temperature resistance is required, and the peelability of the masking material after baking must be ensured in order to facilitate the finishing operation.
3. Clean dust
Using manual or automatic dust removal process, the dust and adhesive adhered to the workpiece surface are completely removed to ensure adhesion between the workpiece and the coating.
Commonly used dust removal devices include compressed air dust removal and electrostatic dust removal.
4. Spray primer
The spray primer is a media layer between the coated article and the coating thereon.
A. Has a high degree of anti-corrosion.
B. Has a certain degree of filling.
C. easy to show the surface defects of the workpiece, easy to make up the soil.
In the coating process, it is necessary to control the spraying distance, paint viscosity, spray pressure and ambient temperature and humidity.
Basic composition of paint
The primers chosen for different materials are also different. This depends on the composition of the coating, the nature of the coating and other factors.
A. Film-forming substances (oil, resin)
B. Pigments (coloring pigments, extender pigments, anti-rust pigments)
C. Solvent (true solvent, co-solvent)
D. Additives
Film forming material
1. Oil (dry oil, semi-dry oil)
The iodine value is used to measure the degree of unsaturation and drying speed of the oil. The so-called iodine value is the number of grams of iodine that can be absorbed by one hundred grams of oil under standard conditions. Oils with an iodine value below 100 grams are called non-drying oils. Iodine values between 100 and 140 grams are called semi-dry oils, and more than 140 grams are called dry oils.
2. Resin: natural resin, synthetic resin.
Paint
1. Coloring pigments: It mainly covers and decorates in the paint. Can improve the physical and chemical properties of the film.
2. Stretch pigments: also known as filler pigments, is a powder without the ability to cover and coloring, can reduce the cost of paint, increase the thickness of the paint film, improve the mechanical properties of the paint film.
3. Anti-rust pigment: It can prevent the corrosion of metal.
Solvent
1. True solvent: An organic solvent that has a diss
