Among many metal materials, aluminum is widely used because of its easy processing, good visual effect and rich surface treatment means. The surface treatment of aluminum profiles is mainly divided into: sandblasting (forming a matte pearl silver surface), polishing (forming a mirror surface), brushing (forming a satin-like effect), electroplating (covering a layer of other metals) and spraying (covering other non-metallic coatings).
Let’s learn about the many surface treatments for aluminum die casting!
1. Sandblasting (shot blasting)
The process of cleaning and roughening the metal surface by using the impact of high speed sand flow. This method of aluminum parts surface treatment can make the surface of the workpiece to obtain a certain degree of cleanliness and different roughness, so that the mechanical properties of the surface of aluminum alloy die-castings are improved, therefore improving the fatigue resistance of aluminum alloy die-castings, increasing the adhesion between it and the coating, extending the durability of the coating film, and also facilitating the leveling and decoration of the coating. The process we often see in various products of Apple, as well as being the existing TV face shell or frame is also increasingly used.
2. Polishing
The use of mechanical, chemical or electrochemical methods to reduce the surface roughness of aluminum alloy die casting to obtain a bright, flat surface processing methods. Polishing process is mainly divided into: mechanical polishing, chemical polishing, electrolytic polishing. Aluminum alloy die casting using mechanical polishing + electrolytic polishing can be close to stainless steel mirror effect, giving a high-grade simple, fashionable future feeling (of course, easy to leave fingerprints also need more care), small die-casting companies are using mechanical polishing, large die-casting companies with chemical electrolysis with more.
3. Drawing
Metal drawing is the manufacturing process of repeatedly scraping lines out of aluminum alloy die castings with sandpaper. Wire drawing can be divided into straight wire drawing, messy wire drawing, rotary wire drawing and thread drawing. Metal brushing process, can clearly show every fine trace, so that the metal matte in a fine hair luster, the product is both fashion and technology, many customers like this surface treatment, is also a lot of die-casting companies commonly used in the surface treatment process.
4.High gloss cutting
The diamond cutter is reinforced by a precision engraving machine on a high-speed rotating (generally 20,000 rpm) precision engraving machine spindle to cut parts, producing a local highlight area on the surface of aluminum die castings. The brightness of the cutting highlight is affected by the speed of the milling drill, the faster the speed of the drill the brighter the cutting highlight, and vice versa, the darker and easier to produce knife patterns. High-gloss high-gloss cutting in the use of cell phones in particular, such as iphone, in recent years, some high-end TV metal frame using high-gloss milling process, coupled with anodic oxidation and brushing process makes the TV overall full of a sense of fashion and technology sharpness.
5. Anodizing
Anodic oxidation is the electrochemical oxidation of a metal or alloy. Aluminum alloy die castings are subjected to a corresponding electrolyte and specific process conditions to form an oxide film on the aluminum product (anode) due to the action of the applied current. Anodic oxidation 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, which has become an indispensable part of aluminum surface treatment and is the most widely used and successful process.
6. Two-color anodizing
Two-color anodizing is the process of anodizing aluminum alloy die castings and giving different colors to specific areas. Two-color anodizing is more costly because of the complexity of the process; however, the contrast between the two colors can better reflect the high-end and unique appearance of the product.