Aluminum casing of gas meter to be electrophoretically processed

Cast by a 300T aluminum die casting machine. These aluminum casings are machined by milling, drilling, and tapping. No flash and burrs on the part surface and inside. Manual polishing to get a flat and smooth surface for the electrophoresis treatment.

Application of the Electrophoretic Process on Aluminum Alloy Die Castings

Electrophoresis, full name electrophoretic coating, is a very common post-treatment process for aluminum alloy die castings. It balances corrosion resistance and decorative effect, and has been widely used in many fields at present.

Process Principle and Core Characteristics

Electrophoretic coating is a process that uses an external electric field to make resin and pigment particles suspended in electrophoretic fluid migrate directionally, and deposit on the surface of aluminum alloy die castings to form a uniform organic coating. Its core characteristics are as follows:
 

1. ‌Good coating uniformity‌: Even if the die casting has a complex shape, it can achieve uniform coverage on the entire surface, and the corner positions can also be effectively protected.
2. ‌High coating utilization‌: The utilization rate can exceed 90%. It uses water-soluble coatings with water as the dissolution medium, which greatly reduces the emission of organic solvents and is more environmentally friendly and safe.
3. ‌High automation‌: It is suitable for mass industrial production, the subsequent maintenance is simpler, and the coating is stain-resistant and easy to clean.

Process Flow for Aluminum Alloy Die Castings

Due to the inherent porosity of aluminum alloy die castings, special process control is required. The standard process is divided into three steps:

1. ‌Pretreatment‌: First, remove oil stains on the workpiece surface through alkaline degreasing, then remove the original oxide layer through pickling activation. For castings, sand blasting/shot peening is generally required in advance to remove casting residual impurities and improve the adhesion of the subsequent coating.
2. ‌Core electrophoretic process‌: Immerse the pretreated die casting in the electrophoretic bath, apply a direct current electric field with set parameters, and make the charged coating particles deposit on the workpiece surface. The commonly used voltage range for aluminum alloys is 60-100V, and the electrophoresis time is usually controlled at 1-20 minutes.
3. ‌Post-treatment‌: After electrophoresis, it first undergoes ultrafiltration water washing to recover residual coating, then enters the baking process to cure the coating, so that the coating is finally formed, and the bonding force and hardness are improved.

Performance Advantages and Application Scenarios

Compared with the pure anodizing process, the aluminum alloy die casting treated by the electrophoretic process has obvious advantages:

1. Better corrosion resistance: The dense organic coating can effectively block the erosion of acid, alkali, and salt, and can be used for a long time without corrosion, even in harsh environments.
2. Stronger decoration: It can achieve a variety of appearance effects, such as gold, black, color, etc. The gloss and transparency can be adjusted to meet different design requirements.
3. Suitable for mass production: With a high degree of automation, the stability of mass production is better than many traditional treatment processes.

At present, this process is mainly used in aluminum alloy die casting products that have dual requirements for appearance and corrosion resistance, such as auto parts, structural hardware, and architectural decorative components.

More information on aluminum die casting parts manufacturing and free quote: cnkylt@aliyun.com