Application of Gravity Die Casting and Its Benefits

Gravity die casting is used to manufacture cast parts from non-ferrous materials such as aluminum or low-temperature alloys. The process is used to manufacture complex-shaped castings for a wide range of industrial applications in the defense, medical and energy sectors. It involves pouring molten metal under gravity into a pre-formed block of cast iron that is fully machined to produce a mold.

1. What are the benefits of gravity die casting?

Unlike the pressure die process, such as semi solid die casting, the gravity die casting process, as it involves pouring the alloy from a vertical position, allows for rapid venting or displacement of air. Low residual gas levels in the mold produce castings with high integrity and good surface finish. Pouring metal also avoids the problem of "critical meniscus velocity", where metal introduced into the mold too quickly risks folding on itself.

gravity die casting produces parts with much smoother surfaces than sand casting; while generally better suited for larger, thicker parts than die casting, it can also produce parts with a high level of detail. The option to use a sand core in the gravity die-casting process allows for more complex designs and greater flexibility during operation.

Although the pouring of the metal is slower than the injection method used in die casting, the alloy is able to cool and solidify quickly because gravity die casting uses a hardened steel mold. This means the part is both strong and ductile, and has a finer grain structure. Modifying the thickness of the mold walls also aids in directional solidification, thereby reducing the possibility of shrinkage defects.

Compared with other equivalent manufacturing processes including silica sol casting, gravity die casting has high productivity, can produce hundreds of castings a day; has excellent dimensional accuracy, provides durability and dimensional stability; has versatility, can design complex and simple shapes; Offers higher tensile strength and better mechanical properties than sand casting; offers a variety of finishes to produce smooth or textured surfaces; requires minimal finishing.

2. What is gravity die casting suitable for?

Several factors should be considered when deciding on the most suitable casting process or vacuum investment casting process for your purposes. Considerations include quality requirements such as surface finish, complexity, mechanical properties, and integrity, further production-related factors include productivity, lead times, and process flexibility, as well as overall commercial considerations.

Gravity die casting is more suitable for shorter production speeds than pressure die casting, and the initial mold cost is also lower. It also works with a wider range of alloys, including brass, zinc, magnesium and Mazak, although metals with higher melting points are not. The parts produced by gravity die casting, while heavier than those produced by pressure die casting, are thinner than the less precise sand casting method.

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