If you are designing an aluminum part, it is important to consider the manufacturing process that will be used to produce it. There are various methods to choose from, and one of the most popular options among designers is aluminum die casting.

For many telecommunications, industrial, and automotive products, aluminum die casting is the preferred method. It can also be used to produce lighting, hydraulic, and electrical components. If you want to know more about the aluminum die-casting process and determine if it is the best option for your application, then you are in the right place.

Overview of the Aluminum Die Casting Process

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Generally, the aluminum die casting process is a metal-forming method that allows you to create complicated aluminum parts. Blocks of aluminum alloy will be heated to extremely high temperatures until they are completely molten.

The melted aluminum will then be injected into the cavity or mold under high pressure. The mold is usually made up of two halves. Once the molten aluminum becomes solid, the mold will be separated to expose the cast aluminum component.

As a result, you can have a precisely formed aluminum product that has a smooth surface, which means that it only requires less or no machining at all. With steel dies, you can use them several times before they deteriorate. That is why aluminum die casting is a great option to produce high-volume aluminum parts.

Benefits of Aluminum Die Casting

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Compared to other metal-forming methods, the aluminum die-casting process offers a lot of benefits, making it the appropriate option for creating aluminum components. One of its remarkable benefits is its ability to generate very intricate shapes that cannot be achieved by machining or extrusion.

An ideal example of this is the generation of complicated automotive parts such as engine blocks and transmissions. Other methods would not be able to consistently achieve the intricacy and tight tolerances required for these parts.

Other advantages include its capability to produce both smooth and textured surfaces as well as its ability to produce both large and small components.

Lightweight

The products that are produced by aluminum die casting are extremely lightweight. The reason behind this is that aluminum is considered one of the lightest metals. That is why it is perfect for several applications where weight is a major consideration.

Durable and Strong

Aluminum die casting is a particular method wherein durable and solid components are produced. In this process, the molten aluminum is injected into the mold, then it will cool down and will harden. As a result, you can have stronger and more durable parts compared to those that are produced from other processes including machining.

Corrosion Resistant

Another important advantage is that aluminum is highly corrosion resistant, which is perfect for applications where the major concern is exposure to the elements. This corrosion resistance is made possible since aluminum is capable of producing a protective oxide layer once it gets exposed to air, hence, further oxidation can be prevented.

Cost-Effective

When it comes to cost, aluminum die casting is highly cost-effective. This process is extremely simple and will not require any expensive material or equipment. In addition, since the parts generated are durable and solid, then you can guarantee that it will last for a long time with proper care.

Recyclable

Aluminum die casting is environmentally friendly since it uses highly recyclable material. In fact, more than 75% of the aluminum produced can still be used nowadays because of its recyclability. That is why this is the perfect option for applications where the major concern is sustainability.

Important Things to Consider During Part Design

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When designing the part for casting, there are certain factors that should be considered. First, the mold should be designed in such a way that it can be separated once the part has solidified. The line indicating where the mold should be separated is known as the parting line, and this should be considered during the early phase of die design.

Another important factor is the placement of the injection points. In cases where the melted metal hardens before reaching every crevice in the die, it is important to have numerous injection points. It would also be great if cavities are incorporated into the design, as aluminum can be placed around them and still separate, revealing the part.

The thickness of the part’s walls is another important consideration due to the latest technological developments. Typically, there are no guidelines when it comes to the minimum wall thickness due to the latest technology developments. However, it is always preferable to have a consistent thickness on the walls.

Comparing Aluminum Die Casting with Permanent and Green Sand Mold Casting

Permanent and green sand mold casting are two popular alternatives to the aluminum die-casting process. In the green sand process, wet sand is used to create the mold for the cast, making it less expensive compared to the other two processes. In die-casting, molten metal is injected into the mold. However, with permanent mold casting, the melted aluminum is gravity-poured into the die, and this process can create stronger casts.

However, aluminum die casting remains the best option for achieving smooth surfaces and better tolerances. In most cases, there is no need for any subsequent surface treatment.

Different Options for Finishing and Machining

Die cast aluminum components usually require fewer machining options, which allows for numerous surface finishing options. Although die casting produces an excellent surface finish, it may still have some flaws such as metal seams, which are the parts where the mold halves connect with each other.

If the part has a rough surface and other flaws, it can be resolved by orbital sanding, sandblasting, or sanding. To improve fatigue resistance, the cold working process is often utilized. Another alternative is to apply a decorative or protective coating, such as a powder coat, on the finished part. After casting, there are other types of alterations that can be applied, such as drill tapping.

Commonly Used Alloys for Aluminum Die Casting

Some of the most common aluminum alloys used for aluminum die casting include 383, A413, CC401, A380, B390, and A360. The most important consideration when selecting the proper alloy is your desired application. For instance, A360 provides superior fluidity when molten, extreme corrosion resistance,  and pressure tightness. While B390 offers high hardness and excellent wear resistance but has the lowest ductility compared to the other cast alloys. That is why this is commonly used for automotive applications such as engine blocks.

Among these aluminum alloys, Alloy A380 is the ideal option since it provides a perfect blend of casting and product properties. Additionally, it is also the most used alloy for casting several products.

Conclusion

Ultimately, the metal-forming method that you choose will greatly depend on the intended purpose of your aluminum component, your budget, as well as the number of parts that you want to produce.  Although die casting can be an expensive option, however, it is worth it if your part requires more quantity and extreme complexity.

SEI Castings offer a wide variety of high-quality casting products. If you want to know more about our casting parts, you can email us at sales@seimw.com.