After die-cast aluminum accessories are cast, post-processing is a key step to improve their performance and quality. These processes act on accessories in different ways, improving their performance from the surface to the inside, so that accessories can better adapt to various usage scenarios.
Machining is the most basic post-processing method. During the die-casting process, accessories may have dimensional deviations and uneven surfaces. Through turning, milling and other mechanical processing, the size can be corrected to make the accessories more accurately fit other parts. At the same time, machining can also remove burrs and flash on the surface of accessories. These defects not only affect the appearance, but also may form stress concentration points during use, causing cracks in accessories. After machining, the surface of the accessories is smoother, the assembly is smoother, and the safety of use is also improved.
Surface cleaning can further improve the appearance and quality of accessories. After die-casting, the surface of accessories often has impurities such as oxide scale and release agent. Cleaning processes such as sandblasting and shot blasting can completely remove these contaminants. A clean surface not only makes the accessories look more beautiful, but also exposes hidden tiny pores, shrinkage and other casting defects, which is convenient for subsequent targeted repairs. In addition, the rough surface after cleaning also provides better conditions for the subsequent coating adhesion and enhances the bonding force between the coating and the accessories.
Anodizing is an important process to improve the corrosion resistance and aesthetics of accessories. Although aluminum can naturally form an oxide film in the air, its protective ability is limited. Anodizing can generate a thicker oxide film on the surface of aluminum. This film has high hardness and dense structure, which can effectively block corrosive media such as water and oxygen, greatly enhancing the corrosion resistance of accessories. Moreover, the porous structure of the oxide film can absorb dyes to achieve different color effects to meet decorative needs. Whether it is the housing of outdoor lamps or the housing of electronic equipment in daily contact, anodizing can significantly improve its durability and visual effect.
Electroplating and chemical plating can give accessories special functions. Through electroplating, copper, nickel, chromium and other metal layers are plated on the surface of accessories to increase surface hardness, improve conductivity, or enhance aesthetics. For example, the surface of accessories after chrome plating is bright and wear-resistant, and is often used in bathroom and automotive decorative parts; chemical nickel-phosphorus alloy plating does not require electricity, and can form a uniform coating on complex surfaces, which is suitable for processing accessories with irregular shapes. In addition, electroplating can also be used to achieve electromagnetic shielding functions to meet the special needs of electronic equipment.
The heat treatment process focuses on optimizing the internal organization and mechanical properties of accessories. Some die-cast aluminum accessories need to bear large loads during use. Through solid solution aging treatment, the alloy elements in the aluminum alloy can be fully dissolved and the strengthening phase can be precipitated, so that the strength and toughness of the accessories are significantly improved. For accessories that need to be welded, pre-welding annealing can eliminate internal stress and reduce the risk of cracks during welding; post-welding aging can restore the performance of the welding area and ensure the reliability of the overall structure.
The coating process provides comprehensive protection for accessories. Spraying paint or powder coating forms a protective layer on the surface of the accessories to isolate the external corrosive medium and meet different decorative needs. Epoxy primer has strong adhesion and good anti-corrosion effect, and polyurethane topcoat has good weather resistance. The combination of the two has better protection effect. The coating formed by the powder spraying process has high hardness and scratch resistance, and is often used in the fields of construction and home appliances. Special functional coatings, such as high-temperature resistant paint and insulating paint, can also allow accessories to adapt to special environments such as high temperature and electricity.
In practical applications, multiple post-processing processes are often used in combination. For example, the size of a car wheel will first be corrected by machining, then sandblasted, anodized, electrophoretically coated, and finally sprayed with varnish. Through a series of treatments, the strength and corrosion resistance of the wheel are guaranteed, while also presenting a beautiful appearance. These post-processing processes complement each other, improving the performance of die-cast aluminum accessories from different angles, allowing them to play a more reliable role in various products.
