How to beautify the appearance of automobile sheet metal?

2019-07-25 10:20:06

When automobile sheet metal parts are processed in various kinds of custom cabinet chassis, air conditioning sheet metal parts, they need to be surface treated, such as spraying, electroplating, anode, electrophoresis and so on. Because some sheet metal materials do not have the function of anti-rust and anti-corrosion, surface treatment is needed to achieve the effect of anti-rust and anti-corrosion. In addition, surface treatment can also achieve the effect of beautifying the appearance of products.

Automobile sheet metal parts

The main purpose of surface treatment is to improve the service life of automotive sheet metal products in harsh environment (i.e. anti-rust and anti-corrosion ability); to obtain the required surface effect or function (i.e. to meet the appearance requirements of sheet metal products).

In order to meet the above needs, the surface treatment technology of sheet metal products mainly includes:

1. Galvanizing: The process of forming a uniform, compact, well-bonded metal or alloy deposit on the surface of the workpiece by electrolysis.

2. Chromium plating: The process principle is the same as that of galvanizing. The corrosion resistance of chromium coating is very strong, 7-10 times that of galvanizing, and the surface is beautiful, but the cost is high.

3. Spraying: The powder is polarized, and under the action of electric field, it is evenly attached to the surface of products with opposite polarity. It belongs to physical change. The coating (powder) is polarized by electrodes, and the object to be sprayed is charged with opposite charges. Under the action of electric field, the powder is evenly attached to the surface of the object. Powder electrostatic spraying will not cause air pollution, powder can be recycled to reduce the cost of material consumption, film performance is superior acid-resistant, alkali-resistant, salt-resistant corrosion, high adhesion.

Automobile stamping parts

4. Electrophoresis: Under the action of anode and cathode, charged coatings ions move to the surface of products and deposit to form coatings. It belongs to chemical change. The electrophoretic paint film has the advantages of fullness, uniformity, smoothness and smoothness. The hardness, adhesion, corrosion resistance, impact performance and permeability of the electrophoretic paint film are obviously better than those of other coating processes. The most common electrophoretic colours are black, and other colours are also available.

Automotive Parts and Components

5. Immersion: Metal immersion is a new technology for anti-corrosion of metal surface. Immersion is a heating process. Metal preheating, immersion and solidification. When impregnating, the heated metal sticks to the surrounding material. The hotter the metal is, the longer the impregnating time is, and the thicker the material is. Immersion moulding is widely used: with rich color, good protection, excellent cold resistance and heat preservation, as well as acid and alkali resistance.

Spraying paint is usually sandblasting, sandblasting mainly uses compressed gas or high-speed rotating impeller to accelerate the impact of abrasives on the surface of the matrix, remove oil, rust and residues, make the surface of the matrix clean and coarser, and also make the surface produce internal stress, which is beneficial to improving fatigue strength.

Sandblasting process, the process is also exquisite, need to pay attention to:

1. The surface before sandblasting must be clean, oil-free and non-humid to avoid contaminating sand grains.

2. Single-sided sandblasting is easy to deform and is not recommended.

3. Sandblasting is impacted by high-pressure gas, which makes the workpiece easy to deform. Therefore, it is necessary to have a solid fixture as a support, and strong air flow to the four shallow sand grains, which has a certain impact on the hardware parts of the contact surface.

4. Under the action of external force (such as bending, die forming, etc.), the sand grains of sandblasted workpieces are easy to fall off or cause obvious indentation.

5. There are many types and specifications of sand grains, which should be selected according to the structural requirements and the size, shape and hardness of the parts.