The choice of sheet metal surface treatment

The choice of sheet metal surface treatment

Sheet metal processing is a mature production technology. Sheet metal parts are manufactured by laser cutting, bending, welding, stamping and other forms of deformation. At the completion of sheet metal manufacturing, different surface treatment processes will be selected according to the purpose.What kind of surface treatment to choose is also very important, let us know more about it!

1. Bead Blasting

Bead blasting is a finishing process that involves shooting thousands of tiny abrasive particles (such as glass or sand) at the sheet metal part surface using compressed air. The sustained impact of these tiny beads on the metal’s surface creates smooth sheet metal surface finishes with matte textures.

Bead blasting is a fairly standard sheet metal finishing process. However, it is also ideal for cleaning or removing paint from finished parts. The visual quality of bead-blasted metal parts makes the post process a popular option for visual applications that require a matte quality. Consequently, it is one of the common aluminum sheet metal finishes you can use for parts that require high visual quality. Bead blasting can also be followed by other finishing processes if needed, and it is ideal for parts that require cosmetic properties

   2. Anodizing

Anodizing is another sheet metal finishing solution used for aluminum and titanium sheet metal parts. It is a technique that uses an electrochemical process to create a corrosion-resistant layer on the surface of the sheet metal part.

The process involves submerging a sheet metal part into an acid electrolyte bath and exposing it to an electric current. The combination of these elements results in the conversion of the sheet metal part’s surface into an anodic oxide layer that is fully integrated into the part surface.

The process is only compatible with aluminum and titanium metals and is available in three variations: Type I, Type II, and Type III.

Type I anodization involves using chromic acid to create thin layer sheet metal finishes on the sheet metal surface.

Type II anodization results in a strong corrosion-resistant layer by using sulfuric acid instead of chromic acid.

Type III/Hardcoat anodization, results in thicker sheet metal finishes that are corrosion resistant and wear-resistant.

Anodization can also impart a variety of surface finish colors. It is a common finishing process in producing mechanical parts, aircraft and automotive components, precision instruments and more.

3. Powder Coating

Powder coating is an aesthetic finishing process that consists of spraying powdered paint onto the surface of a material. In sheet metal fabrication, the sheet metal is then baked to paint bonds to its surface. This creates a strong layer that is corrosion resistant and wear-resistant. Therefore, powder coating is superior to more conventional painting methods because it creates a strong layer outside the component.

Powder coating is available in many colors (including any RAL code or Pantone hues) to meet the client’s aesthetic and brand requirements. It is also available in various sheet metal finishes, such as glossy, semi-glossy, flat, metallic and textured. Prices for powder coating are variable depending on the color, finish and part geometry.

4. Electroplating

This is another popular sheet metal finishing process in which fine layers of another type of metal (sacrificial metal) are deposited on the sheet metal part’s surface. Electroplating occurs by placing the sacrificial metal on the anode position and the sheet metal part on the cathode position. Both metals are placed inside an electrolyte similar to the anodic material. The two types of metal are then chemically bonded through electric conduction.

There are several options for the electroplating material, each of which provides a different combination of properties. At RapidDirect, we can electroplate sheet metal parts using tin, nickel and electroless nickel. It is important to note that if electroplating is used, then tolerances of the original part should account for the final plating’s thickness.

Electroplating can increase conductivity (depending on the sacrificial metal) and increase a part’s resistance to radiation and is thus commonly used to produce radiation shields.