Vacuum Casting is a copying technique used for the production of small series of functional plastic or rubber parts. Using two-component polyurethanes and silicone molds, Vacuum Casting is known for its fast production of high-quality prototypes or end-use products. Vacuum casting works as a bridge for prototyping and production, the process can be used when there are intricate details and undercuts on the mold.
How Does Vacuum Casting Work?
1. High-Quality Master Model
Vacuum casting process requires a high-quality master model. The high-quality master model can be the industrial part like CNC machining PMMA master model. Additionally, you can use a model created by using stereolithography, which is a case for the prototyping applications. CNC PMMA high polish model is suggested if requires a glossy surface.
You should always ensure that the master model being used is of the correct dimensions and beautiful surface. This is to ensure that no flaws are transferred to the model prototype after finishing the process.
2.Cure Silicon Mold Process
The master model is then encapsulated into aluminium box with liquid silicon material. The mold is cured under high temperatures to ensure that liquid silicon become solid. This is used to strengthen the mold and make it more durable. After the mold is made, it is cut open to reveal a hollow space at the center, which has the exact dimensions of the master model. After the mold is cut into two, it is placed in the vacuum chamber. Then, later on, the mold is filled with the required material to cast a product.
3.Filling the designated Material
It should fill the mold with the designated material. The resin replicates the characteristics of industrial material.(Like ABS, PC, PMMA...)The resin material is usually mixed with metallic powder or any coloring pigment to achieve aesthetic or specific functional properties. After the mold is filled with the resin material, it is placed in the vacuum chamber. It is placed in the vacuum chamber to ensure that there are no air bubbles in the mold. This is to ensure that the final product is not ruined or damaged with defects.
4.Final Demoulding Process
The resin is placed in the oven for a few hours the final cured stage. The mold is cured in high temperatures to ensure that the material is strong and durable.(Different resin would be slightly different) The silicone mold is removed from the mold so that it can be used in making more prototypes. Normally it can be up to 20+ to 50 parts for a silicon mold.We will store the silicon mold for 6 months. After the prototype is removed from the mold, it is painted and decorated. The painting and designs are used to ensure that the product has a perfect desired final look.