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How Does Vacuum Casting Rapid Prototyping Work?

by Whitney

Before grabbing a product from the market, have you ever considered its manufacturing? For instance, many products are assemblies of different parts combined. They are manufactured using different processes. Vacuum Casting parts manufacturing is such an example.

Vacuum casting rapid prototyping is a popular and effective method for creating high-quality, low-volume plastic parts. This process is often used in the product development cycle to produce prototypes for testing, validation, and even limited production runs.

This blog post exclusively educates you on rapid prototyping and how it works. Keep reading to learn the details. Grab the basics first.

What is Vacuum Rapid Prototyping?

Vacuum casting is a casting process that uses silicon molds to create metal parts with the help of a vacuum. In rapid prototyping, however, the process uses a silicone mold to create plastic parts. The process is also known as silicone casting or urethane casting. It is an excellent way to create dimensionally accurate parts, has a smooth surface finish, and is visually appealing.

Let’s navigate to the next heading to see how it works.

How Does It Work? – The Process of Vacuum Casting Rapid Prototyping

1. Starts with Designing and Making the Model

It starts with the conversion of paper-drawn drawings to 3D models.

In vacuum casting rapid prototyping, the process begins with creating a master pattern or model. A team of skilled engineers usually performs this activity with the help of CNC machining and SLA. The master model is then used to create a silicone mold.

2. Creating the Silicon Mold

The silicone mold is created by placing the master pattern into a vacuum container and pouring polyurethane around it. The silicone is then cured, creating a negative impression of the master pattern.

Once the silicone mold is created, it is ready for vacuum casting. First, the mold is placed into a vacuum chamber. The vacuum chamber removes any air bubbles from the mold, which could cause defects in the final part. Once the mold is in the vacuum chamber, a vacuum pump draws air out of the chamber, creating a vacuum.

3. Pumping Resin into the Mold

Next, a two-part liquid plastic resin is mixed and poured into the mold. The mold is then placed back into the vacuum chamber, and the vacuum pump is used to draw the resin into the mold. The vacuum pressure helps to ensure that the resin fills the mold evenly and completely, resulting in a part with uniform thickness and no air pockets or voids.

After the resin has been drawn into the mold, it is left to cure for several hours. Once the resin has cured, the mold is removed from the vacuum chamber, and the part is removed from the mold.

The final part is then finished and cleaned up as necessary. This may include trimming excess material, sanding, polishing, or painting. The resulting part is a high-quality, dimensionally accurate replica of the master pattern.


Vacuum casting rapid prototyping is a powerful tool for creating high-quality plastic parts quickly and affordably. Many businesses have found it ideal for producing accurate parts. With its ability to produce accurate, detailed parts with complex geometries and undercuts, it has become an essential part of the product development process for many businesses.

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