01. Anodizing
Anodizing：It is mainly the anodizing of aluminum, which uses the principle of electrochemistry to form a layer of Al2O3 (alumina) film on the surface of aluminum and aluminum alloy. This oxide film has special characteristics such as protection, decoration, insulation, wear resistance, and so on.
Technological Process:
Technical Features:
1. Enhance the strength.
2. Achieve nickel-free sealing to meet the requirements of Europe, the United States, and other countries for nickel-free.
Technical difficulties and key points for improvement：
The yield level of anodization is related to the cost of the final product. The key to improving the yield of anodization lies in the appropriate amount of oxidant, suitable temperature, and current density, which requires structural component manufacturers to constantly explore and seek breakthroughs in the production process.
02. ED-Electrophoresis deposition
Electrophoresis：Used for stainless steel, aluminum alloy, etc., can make the products show a variety of colors, and maintain metal luster, while enhancing surface properties, with good anti-corrosion performance.
Technological Process: pretreatment→electrophoresis→drying
Technical Features:
Advantages：
1. Rich in colors.
2. No metal texture, can cooperate with sandblasting, polishing, wire drawing, etc.
3. When processed in a liquid environment, the surface treatment of complex structures can be realized.
4. The process is mature and can be mass-produced.
Disadvantages：The ability to cover up defects in general and electrophoretic electrophoresis of die castings requires higher pre-treatment.
03. Micro-arc Oxidation (MAO)
Micro-arc oxidation：The process of forming ceramic surface film by applying high voltage in electrolyte solution (usually weak alkaline solution) is the result of the synergistic effect of physical discharge and electrochemical oxidation.
Technological Process: pretreatment → hot water washing → MAO → drying
Technical Features:
MAO surface SEM image （Left) VS anodized surface SEM image （Right）
Advantages：
1. Ceramic texture, dull appearance, no highlight products, delicate feel, fingerprint protection.
2. A wide range of substrates,: Al, Ti, Zn, Zr, Mg, Nb, and its alloys, etc.
3. The pretreatment is simple, the corrosion resistance and weather resistance of the product is excellent, and the heat dissipation performance is good.
Disadvantages：At present, the color is limited, only black, gray and other more mature, bright color is difficult to achieve at present; the cost is mainly affected by high power consumption, which is one of the highest costs in surface treatment.
04. PVD
Physical vapor deposition，PVD：It is an industrial manufacturing process, and it is a technology that mainly uses physical processes to deposit thin films.
Schematic diagram of PVD principle
Technological Process: Cleaning before PVD → vacuuming in the furnace → cleaning target and ion cleaning → coating → coating finished, cooling out of the furnace → post-processing (polishing, AFP)
Technical Features: PVD (Physical Vapor Deposition ) can be used to coat the metal surface with high hard plating and high wear resistance cermet decorative coating.
05. Electroplating
Electroplating：It is a technology that uses electrolysis to attach a layer of metal film to the surface of metal so as to prevent corrosion, improve wear resistance, electrical conductivity, reflectivity and beauty.
Technological Process: Pretreatment→cyanide-free alkaline copper→Cyanide-free copper-nickel alloy tin→Chrome plating
Technical Features:
Advantages：1. High glossiness and high-quality metal appearance of the coating. 2. The substrates are SUS, Al, Zn, Mg, etc., and the cost is lower than that of PVD.
Disadvantages：The environmental protection is poor, and the risk of environmental pollution is high
06. Powder coating
Powder coating：
The powder coating is sprayed to the surface of the workpiece by using powder spraying equipment (electrostatic spraying machine). Under the action of static electricity, the powder will be uniformly adsorbed on the surface of the workpiece to form a powdery coating; the powdered coating is cured by baking at high temperatures. become the final coating with different effects (different kinds of effects of powder coatings).
Technological Process: electrostatic dust removal → spraying → low temperature leveling → baking
Technical Features:
Advantages：
1. Rich colors, highlight and matte are optional.
2. Low cost
3. 100% utilization and environmental protection.
4. Strong ability to cover up defects.
07. Satin
Satin：It is a kind of surface treatment method which forms lines on the workpiece surface by grinding products and plays a decorative effect. According to the different lines after drawing, it can be divided into straight pattern, random pattern, ripple and spin pattern.
Technical Features:Wire drawing treatment can make the metal surface obtain non-mirror metal luster, at the same time, Satin can also eliminate subtle defects on the metal surface.
08. Sandblasting
Sandblasting: It is a process that uses compressed air as the power to form a high-speed jet beam to spray the material to the surface of the workpiece to be treated, so as to change the appearance or shape of the outer surface of the workpiece surface and obtain a certain degree of cleanliness and different roughness.
Technical Features:1. Achieve different reflectors or matte lights. 2. It can clean up the tiny burrs on the surface of the workpiece, make the surface of the workpiece more smooth, eliminate the harm of burr and improve the grade of the workpiece. 3. Clear the residue left over during the pre-treatment, improve the finish of the workpiece, make the workpiece reveal a uniform metal color, and make the workpiece appearance more beautiful and good-looking.
09. Polishing
Polishing：The use of flexible polishing tools and abrasive particles or other polishing media to modify the surface of the workpiece. For different polishing processes: rough polishing (basic polishing process), medium polishing (finishing process), and fine polishing (polishing process), the best polishing effect can be achieved by selecting a suitable polishing wheel and the polishing efficiency can be improved at the same time.
Technical Features: Improve the dimensional accuracy or geometric shape accuracy of the workpiece, get a smooth surface or specular luster, and eliminate the gloss at the same time.
10. Etching
Etching：Usually referred to as photochemical etching, it refers to the removal of the protective film in the etched area after exposure and development, and contact with the chemical solution during etching to achieve the effect of dissolution and corrosion to form a concave-convex or hollowed-out molding effect.
Exposure Method：The project prepares the size of the material according to the graphics-material preparation-material cleaning-drying → film or coating → drying → exposure → development → drying-etching → stripping → OK
Screen Printing Method：Cutting → cleaning the plate (stainless steel and other metal materials) → screen printing → etching → stripping → OK
Technical Features:
Advantages：
1. Fine machining of metal surface can be carried out.
2. Give the metal surface a special effect.
Disadvantages：
Most of the etching liquids (acid, alkali, etc.) are harmful to the environment.
