Surface finish is a process applied to the material surface. To create a protective coating on material surface. Surface finish is a broad range of industrial processes, it is often an important aspect in customized parts. Surface finish applied on aluminium is to improve part’s appearance, enhance its adhesion, corrosion resistance, chemical resistance, wear resistance, electrical conductivity, and remove burrs and other surface flaws. It also play a role in decoration, to make your part more attractive.
Common surface finishes applied on aluminium CNC machined part:
Anodizing is an electrolytic oxidation process. In the electrolytic process, the part to be treated are made an anode in an electrolytic solution. Applying an anode voltage for electrolysis, oxidation occurs at the aluminium machined part surface, resulting in the formation of a coherent oxide film that is very adherent to the underlying metal substrate. It can enhance the surface hardness and wear resistance of aluminum part and prolong its service life. Anodizing is the most widely used of surface finish for aluminium machined part.
Sand blasting is the process of cleaning and roughening the part surface by the impact of a high velocity sand stream. Compressed air is used as the power to spray the sand onto the part surface at high speed. Due to the impact of the abrasive on the part surface and the cutting action, the part surface is given a certain degree of cleanliness and different roughness, so that the mechanical properties and fatigue resistance of part are improved. And it can increase adhesion of coating and extend the durability of the film. We usually do sand blast before anodizing for aluminium machined part.
Powder coating is a process to spray powder onto the surface of a part under the action of static electricity. The powder is uniformly adsorbed on the surface of the aluminium machined part, and the powder coating is cured by high-temperature baking and flattening. The effect of powder coating is superior to the wet painting in terms of mechanical strength, adhesion, corrosion resistance, and aging resistance. It is also environment friendly process.
With pressure or centrifugal force, painting was dispersed into uniform and fine droplets through a spray gun or dish atomizer, applied to the surface of the aluminium machined part. The appearance of wet painting surface is more smooth and bright compare with powder coating surface. Wet painting is widely used for outer parts with higher cosmetic requirement.