Aluminum is one of the most common metals that is used in aluminum castings. It is both lightweight, but extremely study which allows it to function in numerous different applications. While there are concerns of shrinkage and cracks when curing the aluminum casting, following the specific guidelines put out by the industry can allow for the best results.
Making a casting isn’t difficult, but it does require quite a few steps to ensure that it comes out correctly. The first step is to determine the exact geometry of the mold so as to have the correct shape. For basic molds, the cast is made with two parts that are then attached together. When the metal is poured into the mold, it fills all the negative space and when it is solidifies, the manufacturer has the exact mold they wanted.
Now that the mold is made, the next step is to prepare the metal. Metal, naturally, comes in solid state. However, to make it into a mold, it needs to be melted into a liquid. This requires heating it to tremendous temperatures. Once it is liquid, it is poured into a small opening in the mold that is commonly referred to as the gate or riser. Because the metal might have rough edges, an allowance is added so that it can be smoothed off.
Once the liquid metal has been poured, the manufacturer can either wait for it to cool naturally or put it into conditions that speed up the cooling process. Regardless of the method in which the manufacturer takes, the metal has to cool so that it turns into its solid state once again. However, now that it’s in the mold, it will have taken the shape of it when it cooled.
The mold is removed and the casting can then be sent to be used in whatever manufacturing it is needed for. However, typically, it is smoothed out and polished to ensure that the mold fits the exact specifications that the manufacturer needs.
There are a few problems that manufacturers do run in to, though, with aluminum castings. Primarily, it is prone to hot cracks. That means that the cracks appear when it is cooling. To ensure this doesn’t happen, the manufacturer will want to cool it under special conditions to maximize the success of the cooling.
Another problem is its high shrinkage percentage in the range of 2-8%. What this means is that the final casting will be 2-8% smaller than the original product which is not what the manufacturer wanted. Therefore, shrinkage should be taken into consideration when making molds.
Other than that, aluminum is a great metal for making castings which is why so many companies rely on it. Because of its great use, it’s the most common metal that manufacturers use to make molds.
Post time: 01-05-2017