Aluminum stands to be an excellent metal for casting, thanks to its ability to melt well. Though its melting temperature is low, it has a flowing liquid state hence a perfect choice for beginners. It is applied in a number of casting parts to cater to both industrial and non-industrial uses.
There are several methods that manufacturers use to cast aluminum. The quality of aluminum is one of the main factors used to determine the kind of technology to use. By quality, you measure the inside and outside casting, strength, and flexibility. Here’s more that you must know.
Cast Aluminum – Overview
Aluminum casting produces high-precision and quality parts or shapes by pouring molten aluminum into a mold, die, or form. It is commonly used to create delicate and detailed elements that exactly match the specifications of the original design given.
This process is mainly appreciated by industries such as automotive, aerospace, construction, and more. Now, there are various aluminum casting techniques and procedures that manufacturers use to serve the purpose. So stick around if you are looking to know how to cast aluminum like professionals.
There are several types of aluminum casting, each with a unique way of how it is carried out. Let’s take a closer look at how each is carried out!
Sand Casting
Sand casting, as you might know, is among the most popular and oldest methods for casting aluminum. With it, you create a mold using sand and blinders by pressing a template firmly into the sand hence creating a hollow mold space. The molten aluminum is then carefully poured into the mold cavity via an efficient gating system to allow it to solidify and form the desired shape.
Once this is done, the sand mold is broken, and one can collect their aluminum casting. This aluminum casting technique is simple, inexpensive, and perfect for small-scale production.
Investment Casting
Investment casting is an intricate aluminum casting method that’s also known as lost wax casting. With it, you create a wax or thermoplastic pattern invested with a refractory material forming an investment mold.
After the mold is dry, it is heated to melt the wax. With this, you are left with a cavity shaped to the desired casting. The molten aluminum is poured into the mold for dimensionally accurate aluminum casting.
Aluminum casting is able to produce complex castings with a high-quality finish. Additionally, multiple aluminum castings can be made at the same time, and you can get tight dimensional tolerances. This kind of casting is highly applicable to the aerospace, automotive, petroleum, and gas industry.
Die Casting
Aluminum die casting is a high-speed technique. It incorporates a metal mold (known as a die) to create a casting of your choice.
After melting aluminum, it is forced into the mold cavity under high pressure. Once it solidifies, the die can be opened to reveal the finished casting.
This type of casting is perfect when dealing with high-volume production. Also, it is ideal if you can achieve a high level of dimensional accuracy.
Step-by-Step Procedure for Aluminum Casting
Molten aluminum can be dangerous when improperly handled. It requires wearing protective clothing when handling it. Follow the steps below when conducting the aluminum die-casting process. The measures may, however, be similar in any other casting process you choose to use.
Mold Your Desired Design
The first step when casting aluminum is to mold the design. This step largely determines the final shape and property of the cast part.
You can make your mold from different materials such as ceramics, sand, plaster steel, and even aluminum. Ensure that the mold design should be considerate of the shape, size, and surface finish you want to achieve.
At this point, you utilize Computer Aided Design (CAD) to develop the precise specifications of the product being produced. The CAD software designs and molds a 3D product model to be made. Once this is created, it is transferred to a CNC machine that creates the mold.
After you create the mold, prepare it for the casting process. This process involves applying a coat of the release agent to its surface. This helps ensure that the aluminum does not stick to it.
Once this is done, the mold is closed and secured in place for the next step.
Melting the Aluminum
Your mold is ready, so the next important step is to melt the aluminum. The melting point for aluminum is about 660 degrees Celsius, so it quickly melts.
The melting process takes place in a furnace using electricity and gas. Once this is done, it is taken to a holding surface that keeps it at the ideal temperature until it is ready to be poured into the mold.
Pouring the Aluminum on the Mold
The mold and the molten aluminum are ready; now it’s time to pour it. This typically happens through a gate system connecting the mold to the furnace so that it flows in its mold cavity.
In a controlled manner, the metal is poured onto the mold in such a way that air pockets do not form. After the mold is full of metal, all the excess is removed from it. The mold is then designed to let the aluminum cool and solidify.
The Cooling and Solidification Begins
Now, the mold is left to cool and solidify for a while. The period for this process depends on how thick the product being produced is. This process is intricate as it determines the mechanical properties of the cast.
You should control the cooling rate so that the aluminum solidifies evenly. Also, this will ensure that you end up with a product that features your desired properties and specifications.
Remove the Casting from the Mold
The final step in the aluminum casting process is to remove the casting from the mold. Here you trim the excess material and finish the surface. At this point also, you might need to take the cast through additional
processing, such as machining, so that you achieve the shape and size you want.
Cast Aluminum Versus Other Popular Manufacturing Processes
Aluminum casting presents many advantages over other manufacturing methods, such as Gravity Die Casting. Some of the notable benefits for it include:
- High speed for producing items.
- It is relatively cheaper, therefore, a popular choice for those needing small-scale production.
- With it, you can create some of the most complex shapes.
- Aluminum is lightweight with a good strength-to-weight ratio; therefore, ideal for producing items in the automotive and aerospace industries.
As you have seen, the process of casting aluminum is pretty straightforward. It involves designing and preparing the mold, melting the aluminum, pouring it into it, and letting it solidify.
It’s an intensive process that requires extra care so that your final product is as you had designed it. Otherwise, it is an effective manufacturing process that will give you high-quality products at a low rate.
Are you looking for a reliable cast aluminum manufacturer? Look no further than Sunrise Metal. We are experts in aluminum die casting and will provide customized items to suit your needs. Contact us today to get help with your aluminum casting needs!