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1. Introduction to Die Casting

Die casting is a metal casting process that injects liquid or semi-liquid metal into a mold under high pressure to form castings, featuring high efficiency and precision. As a metal casting technique, it occupies a prominent position in the manufacturing industry due to its unique principles. It uses high pressure to rapidly inject liquid or semi-liquid metal into the inner cavity of a mold; after shaping and solidification, castings are finally formed. These molds are usually exquisitely made from higher-strength alloys, and their working principle is quite similar to that of injection molding.

2. Die Casting Equipment and Application Fields

Die casting machines, the core equipment for die casting, are divided into two main types: hot chamber and cold chamber. Their primary difference lies in their pressure-bearing range, which typically falls between 400 and 4,000 tons. Although the initial investment cost for die casting equipment and molds is relatively high, die casting is highly suitable for the mass production of small and medium-sized castings. It is widely used in fields such as automotive, instrumentation, electronic equipment, agricultural machinery, national defense, and medical devices—especially for small-batch to medium-batch production.

3. Unique Features of Die Casting

3.1 Excellent Dimensional Accuracy and Surface Finish

The dimensional accuracy of die castings can generally reach Grade 6-7, and even as high as Grade 4 in some cases, ensuring product precision. Meanwhile, their surface finish is also outstanding, usually reaching Grade 5-8, making the product appearance smoother and more delicate. In addition, die castings have relatively high strength and hardness—their strength can be increased by 25-30% compared to sand casting. This ensures stable product dimensions and good interchangeability, meeting the production needs of complex-shaped and thin-walled precision parts. For example, the minimum wall thickness of zinc alloy die castings can reach 0.3mm, while that of aluminum alloy castings can even reach 0.5mm. The minimum cast hole diameter and minimum pitch are 0.7mm and 0.75mm respectively, fully demonstrating the excellent performance of die casting in terms of dimensions and precision.

3.2 High Production Efficiency

The die casting process can be easily mechanized and automated, greatly improving production efficiency. Cold chamber die casting machines can complete an average of 50-90 die casting cycles per hour, while hot chamber die casting machines can even achieve a high frequency of 400-900 cycles per hour. Furthermore, die casting technology can directly form complex internal structures (such as threaded sleeves, heating elements, and high-strength bearing surfaces), further simplifying the production process.

3.3 Superior Economic Benefits

Due to their high dimensional accuracy and excellent surface quality, die castings can often be used directly without further machining. This not only improves metal utilization but also significantly reduces the need for processing equipment and working hours, thereby achieving substantial savings in machining costs. In addition, combining die casting technology with other metals or non-metallic materials can not only save assembly time but also effectively reduce metal material consumption.

4. Die Casting Materials and Post-Processing

4.1 Common Die Casting Materials

Common die casting materials include zinc, copper, aluminum, magnesium, etc., each with unique properties and application fields. Most castings in the die casting process use non-ferrous metallic materials, such as zinc, copper, aluminum, magnesium, lead, tin, and their alloys. Among them, zinc is the preferred choice for manufacturing small components due to its ease of casting, cost-effectiveness, and high compressive strength and ductility. Aluminum stands out for its lightweight nature, dimensional stability, corrosion resistance, and excellent mechanical properties—especially in the production of complex and thin-walled castings. Magnesium is favored for its good machinability and high strength-to-weight ratio, making it the lightest among commonly used die casting metals. Copper holds a place in the die casting field thanks to its high hardness, strong corrosion resistance, excellent mechanical properties, and wear resistance. Lead and tin, with their high density and extremely high dimensional accuracy, are often used to manufacture special anti-corrosion components.

4.2 Post-Processing Technologies

To further enhance the corrosion resistance, wear resistance, and appearance of products, die castings undergo a series of post-processing steps after production. These include processes such as tapping, polishing, and laser engraving, as well as quality inspection procedures like ultrasonic cleaning and leakage testing.