Ceramic beads sandblasting anodizing process
August 22, 2022
Our industrial aluminum profiles and aluminum alloy electronic product enclosures often use a sandblasted anodized surface finish.
It mainly includes ten major processes: degreasing, alkali washing, neutralization, sandblasting, chemical polishing, neutralization, oxidation, surface conditioning, dyeing, and sealing.
1. Degreasing
Oil removal is to use the infiltration, separation, emulsification, saponification and other functions of the degreaser to remove the oil from the surface of the metal casing of the mobile phone.
2. Alkaline washing, neutralization (also called stain removal)
Alkaline washing is to remove excess grease through the saponification of caustic soda (NaOH), and to remove the natural oxide film, burrs and impurities of the workpiece.
3. Sandblasting
Sandblasting is a processing step prior to anodizing coloring.
Sandblasting is to pass the aluminum alloy workpiece slowly through the sandblasting machine, and the inside of the sandblasting machine will spray very fine ceramic beads to make even small pits on the surface of the aluminum profile, which looks like a matte effect, which is better than the bright appearance. mild. At the same time, sandblasting can also remove surface defects such as burrs, scratches, corrosion spots, blisters, pores, etc. on the surface of the workpiece, and further remove the subtle unevenness on the surface of the workpiece, making it have a higher satin luster.
Ceramic beads has different particle sizes, the larger the number, the finer the ceramic sand, and the smaller the surface roughness of the sandblasting.
Commonly used ceramic beads types are B40, B60, B120 for aluminium profiles and B150, B170, B205 for 3C products.
After ceramic beads blasting, it can provide good surface conditions and improve the quality of surface finishing;
Obtain a clean surface;
Reduce the impact of welding;
produce decorative effects;
Improve product quality;
4. Chemical polishing
Chemical polishing is a method of eliminating wear scars, etching and leveling by selectively dissolving the uneven area of the sample surface by chemical reagents. Chemical polishing mainly includes two-acid polishing and three-acid polishing.
5. Anodizing
Anodizing is a process in which the product that needs an anode is used as the anode, and the stainless steel, chromium, etc. are used as the cathode in the electrolyte; under the condition of electrification, the anode is oxidized, so that the product obtains an anodized film. The best electrolyte is sulfuric acid.
Anodizing can generate uniform film pores with a pore size of 0.01-0.03um and a depth of 5-20um. The oxide film is suitable for dyeing and increases the wear resistance, corrosion resistance and aesthetics of aluminum materials.
6. Surface adjustment
The anodized metal surface has a certain acidity. In order to ensure the dyeing quality, the PH value of the workpiece surface should be adjusted by adjusting the surface. The routine operation of surface conditioning is divided into two ultrasonic waves, each 3-5 minutes.
7. Dyeing
Dyeing is the process of accumulation and precipitation of dyes in the pores of the oxide film by utilizing the adsorption of the pores of the oxide film. Dyes are generally divided into organic dyes and inorganic dyes, among which organic dyes are further divided into acid dyes and basic dyes, and acid dyes are currently the most commonly used dyes.
The main factors that determine the dyeing effect are: the pH value of the dye, the concentration of the dye, the quality of the membrane pores and the temperature.
8. Close
The sealing technology can reduce the activity of membrane pores, fix dyes, increase anti-corrosion, wear resistance and other properties, and make the surface of parts smooth. The sealing agent is divided into "normal temperature sealing agent", "medium and high temperature sealing agent" and "high temperature sealing agent" according to the temperature;
Sandblasting anodizing process application:
Widely used in aviation, electrical, electronic digital industry, machinery manufacturing, automobile, construction, light industry and other industries.
Such as: notebook computer shell, education machine shell, TV frame, TV shell, stainless steel sheet, mobile phone shell, power bank, computer motherboard, electric iron bottom plate, aluminum sheet, profile and other special-shaped parts, etc.