How Does The Process Of Vacuum Casting Work?

by Thomas E.
Vacuum Casting Process

Vacuum casting is a category of casting that involves elastomers. Casting is a process of manufacturing that involves pouring on liquids into a mold that contains the shape of the product, which is to be manufactured in the form of a hollow cavity. In vacuum casting, a vacuum is used to draw liquid material into a mold. The liquid is then left to solidify then the final product is broken out of the mold. It solves one of the most significant problems in the casting process, which is air entrapment. Vacuum casting is also referred to as polyurethane casting. In this write-up, we will be talking about the vacuum casting process.

How does the vacuum casting process work?

  • Requirements

Before embarking on the process of vacuum casting, the first step is to acquire some mandatory objects. The first item you need is a high-quality master model. Some manufacturers of vacuum casting machines make the model as part of the industrially manufactured product. The model is designed that it takes the shape of the final product. Therefore, when acquiring the perfect model, it is essential to make sure that it is of the best dimensions and resembles the product with which it will be used to manufacture.

The next requirement is the liquid that is to be vacuumed into the mold. The type of liquid you choose depends on the object that you will be manufacturing. The liquid is known as resin. The resin needs to be a replicate of the desired characteristics of the final product. The best kind of resin used in vacuum casting is normally mixed with powder and other coloring agents depending on the desired aesthetic features of the end product.

  • The vacuum casting process

The first step of the process is curing. Curing is the process when the mold is attached to a silicone mold with two parts. The process takes place under high temperatures. The temperature helps to ensure that the parts of the machine stick together. It also works to make the machine more durable. 

The next step is to cut the open part of the mold. This is done to reveal the hollow spot that is at the center of the mold. The cut-out space will allow you to feed the resin into the mold. The resin is only fed into the mold after it is prepared according to the characteristics of the product, which is to be manufactured. Once the mold is filled into the mold to completion, it is placed in a vacuum chamber. In the chamber, all air that may have slipped into the mold is eliminated. This helps to ensure that the final product is without a flaw.

Finally, the mold is exposed to extremely high temperatures. The temperatures allow for durability. The final product is then removed from the mold, leaving the mold for future use.


Some vacuum casting machines are designed in such a way that the pressure in the chamber can be increased or decreased. This helps to improve the quality of the final product. Such machines allow the manufacturers to control the processes of mixing, preheating, de-molding, and the removal of gas.

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