You can find plenty of casting options if you want to manufacture parts made from polymer or metal materials. There is sand casting, which is the oldest and cheapest of the ton. On the other end are die-casting or investment casting options.

While these processes may seem simple, they also have several drawbacks. For example, in casting, there is a possibility of air getting trapped inside the mold and material that could result in the formation of air bubbles. These are major defects and could lead to the rejection of parts.

There is one technique that produces the same parts but eliminates the flaws. It is called vacuum casting and it involves a 4-step process to create the part.

How Does Vacuum Casting Work?

If there is a dependable and flexible process that can accommodate complex designs, it is vacuum casting. This manufacturing method may look complicated but the reality is it’s not. And the results are almost perfect, it is frequently used by companies for prototyping and custom products.

Here is a step-by-step look at how vacuum casting works.

Step 1. Creation of the Master Model

The casting model is made through stereolithography. This is a form of 3D printing that is done in a layer-by-layer fashion with the use of photopolymerization. The same technology is used in making prototypes and patterns.

This master model has to be perfect because any flaws will be transferred to the final product. It needs to have the right dimensions and specifications.

Step 2. Curing Process

This master model is encapsulated in a two-part rubber mold for the next process. The mold is subjected to high temperatures to ensure that they stay together. It will also strengthen the mold for the succeeding process.

Once the mold is cured, the mold is cut in the middle and the master model is taken out. It will end with a hollow cavity that has the precise dimensions as the master model. The mold is then placed inside the vacuum chamber for the next step.

Step 3. Resin Casting Using the Vacuum Chamber

The term vacuum casting came from the use of a vacuum chamber. In this third step, the mold will be filled with a designated material. This resin should replicate the properties of the material in final production. Typically, the resin is mixed with coloring pigment or metallic powder to fulfill aesthetics and functional requirements.

When the mold is placed inside the chamber to squeeze out any air bubbles in the mold. The resin is flowing straight into the mold cavity and fills it.

Step 4. Final Curing Process

The final step is to wait for the resin to cure inside the mold. In some cases, the resin is cured using high temperatures to ensure its durability and robustness. The silicone mold, on the other hand, is used for more prototypes. The finished may undergo finishing like painting or decorating, depending on the requirements.

Conclusion

The vacuum casting process can make prototypes or final products without any imperfections because it uses vacuum to remove any air trapped within the resin. With this process, the silicone mold is a cheaper solution in creating a mold. The process is fast and can accommodate low-volume manufacturing.