What Surface Finishes are Used on Aluminum – Common Aluminum Surface Treatment Methods


There are more and more aluminum parts and products applied in different industries, from the protective housing of electronic devices to auto accessories to custom aluminum machined components. Aluminum parts are often treated before they are put into normal use. What are the common surface finishing methods for aluminum alloys and products?

What Surface Finishes are Used on Aluminum - Common Aluminum Surface Treatment Methods

1.  Sandblasting (shot blasting)

The process of cleaning and roughening metal surfaces under the impact of high-speed sand flow. This treatment method of aluminum alloy surface processing parts can make the workpiece surface obtain certain cleanliness and different roughness, improve the mechanical properties of the workpiece surface, thereby improving the fatigue resistance of the workpiece, increasing the binding force between the workpiece and the coating, extending the durability of the coating, and also conducive to the leveling and decoration of the coating. We often see this technology in various products of apple, and it is increasingly used in existing TV housings or middle frames.


2. Polishing

Polishing uses mechanical, chemical, or electrochemical methods to reduce the surface roughness of the workpiece, so as to obtain a bright and flat surface. The polishing process is mainly divided into mechanical polishing, chemical polishing, and electrolytic polishing. After mechanical polishing and electrolytic polishing, the aluminum alloy surface processing parts can adhere to the stainless steel mirror, giving people a high-end, simple, and fashionable sense of the future (of course, fingerprints are easy to leave and easier to care for).


3. Brushed

Brushing is a manufacturing process that uses sandpaper to repeatedly scrape out the aluminum alloy surface machined parts to be processed. The brushed aluminum can clearly show every trace of the thin wire and make the hair shiny in the metal matte. The product has a sense of fashion and technology.


4.  Diamond cutting

The diamond cutter is reinforced by the high gloss cutting machine on the main shaft of the high-speed rotating (generally 20000 RPM) engraving machine to cut parts and produce local bright spots on the product surface. The brightness of the cutting highlight is affected by the rotation speed of the milling cutter. Highlight and highlight cutting are especially suitable for iPhone 5 and other mobile phones. In recent years, some high-end TV metal frames have adopted high light milling technology, combined with anodizing and wire drawing technology, making the whole TV full of fashion and a sharp sense of science and technology.


5.  Anodizing

Anodizing refers to the electrochemical oxidation of metals or alloys. Under the corresponding electrolyte and specific process conditions, aluminum and its alloys form an oxide film on aluminum products (anodes) under the action of external current. Anodizing can not only solve the defects of aluminum surface hardness and wear resistance, but also prolong the service life of aluminum and enhance the aesthetics of aluminum. It has become an indispensable part of aluminum alloy surface treatment and is the most widely used and successful technology at present.


6. Multi-Color Anodizing

Multi-Color Anodizing refers to anodizing products and giving different colors to specific areas. The two-color anodizing process is complex and costly, but the aluminum alloy surface processed parts can better reflect the high-end and unique appearance of the products through the comparison of the two colors.


To sum up, there are some common surface finishing technologies for aluminum alloy machined parts.