What are the different methods of product surface treatment, and how to choose the most suitable economical treatment process？
A thin complementary layer is applied on the surface of the metal product to process the exterior of the metal product. There are various types of metal processing techniques that can be used for multiple purposes. We will review the main finishing machining methods, as well as the applications and considerations for selecting metal finishing machining techniques. Some general advantages of this surface treatment for metal products include:
1. Increased durability
2. Improve decoration
3. Enhanced conductivity
4. Higher resistance
5. Higher chemical resistance
6. Higher resistance to discoloration
7. Vulcanization potential
13 types of common metal surface treatment processes are as follows:
1. Metal plating
2. Surface wire-drawing
3. Polishing
4. Shot blasting
5. Electrolytic polishing
6. Metal grinding
7. Anodizing
8. Sandblasting
9. Spraying
10. Baking paint
11. Blacking
12. Passivation
13. Surface hardening
Metal plating
The process of attaching a metal film to the surface of metal or other material parts through electrolysis, which can play a role in preventing corrosion, improving wear resistance, electrical conductivity, reflection characteristics and improving aesthetics.
What’s the principle of metal plating?
Electroplating needs to provide a low-voltage and high-current power supply to the electroplating tank and requires an electrolysis device composed of electroplating solution, parts to be plated (cathode) and anode. The plating process is a process in which metal ions in the plating solution are reduced to metal atoms by electrode reaction under the action of an external electric field, and metal deposition is performed on the cathode.
Metal surface plating
Surface wire-drawing
Different from electroplating, brushed metal surface treatment is an effective method to remove surface defects. These finishing machines produce a uniform, parallel grain surface texture to smooth the exterior of the product. Abrasive belts or wire brushes are usually used to achieve this effect. In addition, the singular direction of the belt or brush creates slightly rounded edges perpendicular to the texture.
Surface wire-drawing
Polishing
It means the process of rotating parts in batches together with grinding media in the drum at a low speed, and performing the finishing process by the relative movement of parts and abrasives. Rolling is to put the parts into the drum together with the abrasive and the rolling liquid. Due to the rotation of the drum, the parts and parts, the parts and the abrasive, the parts and the barrel wall rub and collide with each other, plus the chemical effect of the rolling liquid, to remove oil stains, rust, burrs on the surface of the parts, and level the metal surface.
Shot blasting
We use s shot blasting device and centrifugal force to do the projection the surface of the work piece at high speed, to do shot blasting, especially the inner cavity of the work piece, achieve the desired brightness, cleanliness, roughness and strengthening the surface, greatly improve the service life and aesthetics of parts.
Shot blasting
Electrolytic polishing
Electrolytic polishing is also called electrochemical polishing. Electrolytic polishing uses the thrown work piece as the anode and the insoluble metal as the cathode. Both poles are immersed in the electrolytic cell at the same time, and direct current is applied to produce selective anode dissolution, thereby increasing the surface brightness of the work piece.
Electrolytic polishing
Metal grinding
Grinding is a precision machining method that uses a grinder and abrasives to grind a very thin layer of metal from the surface of the work piece on the basis of precision machining.
Grinding is divided into manual grinding and mechanical grinding. Grinding uses abrasive particles coated or pressed on the grinding tool, and finishes the processed surface (such as cutting processing) through the relative movement of the grinding tool and the work piece under a certain pressure. Grinding can be used to process various metallic and non-metallic materials. The processed surface shapes include flat surfaces, inner and outer cylindrical surfaces and conical surfaces, convex and concave spherical surfaces, threads, tooth surfaces and other profiles.
Anodizing
Electrochemical oxidation of metals or alloys. The metal or alloy product is used as an anode, and an oxide film is formed on the surface by electrolysis. The metal oxide film changes the surface state and performance, color, improving corrosion resistance, enhancing wear resistance and hardness, and protecting metal surfaces.
Anodizing
Sand blasting
It uses compressed air as the power to form a high-speed jet beam to spray the spray materials (copper ore sand, quartz sand, emery sand, iron sand, sea sand) to the surface of the work piece to be treated at high speed, so that the outer surface of the work piece surface or the shape changes. Due to the impact and cutting action of the abrasive on the surface of the work piece, the surface of the work piece get certain cleanliness and different roughness, and the mechanical properties of the surface of the work piece are improved, so the fatigue resistance of the work piece is increased and increased It improves the adhesion between the work piece and the coating, prolongs the durability of the coating film, and is also conducive to the leveling and decoration of the coating.
Sand blasting
Spraying
Use pressure or electrostatic force to attach paint or powder to the surface of the work piece, so that the work piece has anti-corrosion and appearance decoration effects.
Baking paint
Apply primer and topcoat on the substrate, and each time it is painted, it is sent to a dust-free temperature-baking room for baking.
Piano painted surface
Blacking
It is a common method of chemical surface treatment. The principle is to produce an oxide film on the metal surface to isolate the air and achieve the purpose of anti-rust. When the appearance requirements are not high, blackening treatment can be adopted. The surface of steel parts is blackened, and some are also called blueness.
Passivation
Sometimes are used as a post-treatment coating process, usually as a means of providing additional corrosion protection. Passivation involves the application of metal oxide coatings that extend the time that rust occurs. Passivant are available in a variety of colors, which can also enhance the appearance of the final part.
Surface hardening
One way to protect metal surfaces is to make them harder. An industrial metal finishing process called surface hardening can achieve this goal. Carburizing and hardening is a metallurgical process that increases protection through surface treatment. This can be achieved by implementing one of many techniques, such as micro-casing, carburizing and nitriding. Each of these processes can produce the required hard shell, while the metal inside remains relatively soft. The protective sleeve will ultimately improve the durability and wear resistance of the underlying work piece.
The metal surface treatment described above can be selected according to the material and application of the product. For example, if your operations require fast turnaround time, you need to choose a process that is compatible with your tight production deadlines. Another factor is the hardness of the metal or other substrate you are using. The excessive grinding process may damage the parts, while the excessively slow process may not achieve the desired results.
The final consideration is cost, which is always an important consideration. Spending some time exploring all available pricing methods can help your company save a lot of money.
For example, processes such as electroplating precious metals may not meet your budget. However, you can achieve similar results at a lower overall cost by replacing cheap metals.
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