Surface treatment is to form a surface layer with some or more special properties on the surface of materials by physical or chemical methods. Surface treatment can improve product appearance, texture, function and other aspects of performance. Anodizing anodizing: mainly the anodizing of aluminum, is the use of electrochemical principle, in the aluminum and aluminum alloy on the surface of a layer of Al2O3(alumina) film. The oxide film has the Special Properties of protection, decoration, insulation and wear resistance. Process flow: single color, gradual color: POLISHING/SANDBLASTING/DRAWING → degreasing → anodizing → neutralization → dyeing → sealing → drying two colors: 1 polishing/sandblasting/drawing → deoiling → shading → anodizing 1→ anodizing 2→ sealing → drying 2 polishing/sandblasting/drawing → deoiling → anodizing 1→ radium carving → anodizing 2→ sealing → drying characteristics: 1. Increase in intensity, 2. Implement any color except white. 3. Realizing nickel-free sealing to meet the requirements of countries such as Europe and the United States for nickel-free. 2. ELECTROPHORESIS (ED-Electrophoresis deposition) electrophoresis: used for stainless steel, aluminum alloy, etc. , can make products appear various colors, and maintain a metallic luster, while enhancing surface properties, it has good anticorrosion performance. Process flow: PRETREATMENT → electrophoresis → drying technology features: 1, Rich Colors; 2, no metal texture, can cooperate with sandblasting, polishing, drawing, etc. . 3, processing in liquid environment, can achieve the surface treatment of complex structures; 4, mature process, can be mass-produced. DISADVANTAGES: General Ability to cover defects, electrophoresis of die castings requires high pretreatment, micro-arc oxidation (Mao) , micro-arc oxidation (Mao) : in Electrolyte Solution (generally weak alkaline solution) , the process of applying high voltage to form a ceramic surface layer, the process is the result of synergetic action of physical discharge and electrochemical oxidation. Process flow: PRETREATMENT → hot water washing → Mao → drying technical characteristics:

Advantages: 1, CERAMIC TEXTURE, dull appearance, no bloom products, feel fine, anti-fingerprint; 2, substrate wide: AL, TI, Zn, Zr, MG, NB, and its, alloy, etc. ; 3, pretreatment is simple, the product corrosion resistance, excellent weather resistance, good heat dissipation performance. DISADVANTAGES: The current color restrictions, only black, gray and other more mature, bright colors are difficult to achieve at present; the cost is mainly affected by high-cost film, is one of the most expensive surface treatment. Physical Vapor Deposition (PVD) : PVD is an industrial process in which a Physical process is used to deposit Physical vapor deposition.

TECHNOLOGICAL PROCESS: PVD cleaning → furnace vacuum → target washing and ion cleaning → coating → coating finish, features: PVD (Physical Vapor Deposition) can be used to deposit hard and wear resistant cermet decorative coating on the metal surface. 5. ELECTROPLATING: It is a process by which a layer of metal film is deposited on the metal surface by electrolysis to prevent corrosion, improve wear resistance, conductivity, reflectivity and aesthetics. Technological Process: PRETREATMENT → cyanide-free alkaline Copper → cyanide-free White Copper Tin → chromium plating features: 1. High Gloss coating, High Quality Metal Appearance; 2. Substrate Sus, AL, Zn, MG, etc. . Disadvantages: Poor environmental protection, greater risk of environmental pollution. Metal Wire drawing: It is a kind of surface treatment method to form the line pattern on the surface of the work piece through the grinding product, which has the decorative effect. According to the different lines after drawing can be divided into: straight drawing, random drawing, ripple, twist. Technical Features: non-specular Metallic Luster can be obtained by wire drawing, and fine defects can be eliminated by wire drawing. SANDBLASTING: A process in which a high speed jet beam is formed, powered by a Compressed air, to spray the material at high speed onto the surface of the work piece to be processed, so that the appearance or shape of the outer surface of the work piece is changed to obtain a certain degree of cleanliness and a different degree of roughness. Technical Features: 1, to achieve different reflection or sub-light. 2, can clean the workpiece surface tiny burr, and make the workpiece surface more even, eliminate the harm of Burr, improve the quality of the workpiece. 3, Clear pre-treatment of residual pollution, improve the workpiece finish, can make the workpiece exposed uniform metal color, make the workpiece appearance more beautiful, good-looking. POLISHING: The use of flexible polishing tools and abrasive particles or other polishing media on the surface of the workpiece finishing. Process flow:

Technical features: improve the size of workpiece precision or geometric shape precision, get a smooth surface or mirror gloss, but also eliminate gloss. ETCHING: Commonly referred to as photochemical etching, refers to the exposure plate making, development, will be etching area of the protective film removed, in the etching contact with chemical solution, to achieve the role of dissolution of corrosion, the effect of forming a bump or hollow out. Process flow:

Exposure method: According to the drawing, the size of material preparation-material preparation-material cleaning-drying-film sticking or coating-drying-exposure-developing-drying-etching-stripping-OK screen printing method: opening-cleaning plate (stainless steel other metal material)-screen printing-etching-stripping-OK technical characteristics: 1. Fine machining of metal surface can be carried out; 2, give metal surface special effect defect: the Corrosion Liquid (acid, Alkali, etc.) used in etching is mostly harmful to the environment. Exposure method: According to the drawing, the size of material preparation-material preparation-material cleaning-drying-film sticking or coating-drying-exposure-developing-drying-etching-stripping-OK screen printing method: opening-cleaning plate (stainless steel other metal material)-screen printing-etching-stripping-OK technical characteristics: 1. Fine machining of metal surface can be carried out; 2, give metal surface special effect defect: The corrosion liquid (acid, Alkali, etc.) used in etching is mostly harmful to the environment. 

Source: Product Mechanical Structural Engineer Working Notes