1. Anodizing
Mainly the anodization of aluminum, which uses electrochemical principles to generate a layer of Al2O3 (aluminum oxide) film on the surface of aluminum and aluminum alloys. This oxide film has special characteristics such as protection, decoration, insulation, and abrasion resistance.
Process flow:
Single color, gradient color:
Polishing / sandblasting / wire drawing → degreasing → anodizing → neutralization → dyeing → sealing → drying
Two colors:
①Polishing/sandblasting/wire drawing→degreasing→masking→anodic oxidation 1→anodic oxidation 2→sealing→drying
②Polishing/sand blasting/wire drawing → degreasing → anodizing 1 → laser carving → anodizing 2 → sealing → drying

2. Technical features:
1. Improve strength
2. Realize any color except white
3. Achieve nickel-free sealing and meet the requirements for nickel-free in Europe, the United States and other countries

3. electrophoresis
Used in stainless steel, aluminum alloy, etc., it can make the product show a variety of colors, and maintain the metallic luster, at the same time enhance the surface performance, has better anti-corrosion performance.
Process flow:
Pretreatment → electrophoresis → drying
advantage:
1. Rich colors;
2. No metal texture, can be used with sandblasting, polishing, wire drawing, etc.;
3. Processing in a liquid environment can realize surface treatment of complex structures;
4. The technology is mature and can be mass produced.
Disadvantages:
The ability to conceal defects is average, and electrophoresis for die castings requires higher pre-treatment.
At present, the colors are limited, only black and gray are more mature. Bright colors are currently difficult to achieve; the cost is mainly affected by high power consumption, and it is one of the most expensive surface treatments.

4. PVD vacuum plating
The full name is physical vapor deposition, which is an industrial manufacturing process and a technology that mainly uses physical processes to deposit thin films.
Process flow:
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, physical vapor deposition) can be coated on the metal surface with high-hardness, high wear resistance cermet decorative coating

5.electroplating
It is a technology that uses electrolysis to attach a metal film to the surface of the metal to prevent corrosion, improve wear resistance, electrical conductivity, light reflectivity, and enhance aesthetics.
Process flow:
Pretreatment→Cyanide-free alkaline copper→Cyanide-free copper-nickel alloy tin→Chrome plating
Advantages:
1. The coating has high gloss and high-quality metal appearance;
2. The base material is SUS, Al, Zn, Mg, etc.; the cost is relatively low compared to PVD.
Disadvantages:
Environmental protection is poor, and environmental pollution risks are greater.

6. polishing
Use 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 (coating process), choosing a suitable polishing wheel can achieve the best polishing effect and improve polishing efficiency.
Technical features:
Improve the dimensional accuracy or geometric accuracy of the workpiece to obtain a smooth surface or mirror gloss, and at the same time, it can eliminate the gloss.