+86 13824370059 paulchim@ltproto.com

Vacuum casting, also known as Urethane casting or Polyurethane casting, is a casting process in which a liquid material is drawn into a silicone mold using a vacuum to create complex components. The liquid materials used for vacuum casting are Elastomers such as plastic and rubber. As an excellent adaptable manufacturing process, vacuum casting is capable of producing complex parts with complicated details. Making vacuum casting part is a shortcut for quality validation at early stage. It’s a solution to speed up product development process as vacuum casting can create small batches of high-quality parts in short time. And those parts are suitable for pre-launch product testing, functional testing and validation, concept models and prototypes, etc. Vacuum casting prototyping is an economical manufacturing solution, let’s take a look at the process of silicone vacuum casting.

Vacuum Casting Services Applications:

Vacuum casting can make soft material parts that 3D printing and CNC prototyping cannot make, which is the biggest benefit that make vacuum casting different. That is way vacuum casting still plays an significant role to make prototypes and complement. It is still an irreplaceable and valuable molding technique, and the industry needs it. The way Vacuum casting do likes plastic injection mold do, it means that it can make almost any complex parts that injection mold can make, but the cost in vacuum casting is very low compared to traditional methods such as plastic injection molding and pressure die casting.

Vacuum casting is a highly economical and efficient manufacturing process. Manufacturing

The economical nature of manufacturing makes vacuum casting highly efficient for batch production jobs and rapid prototyping jobs, where limited amounts of products are to be manufactured.

Vacuum casting is not as efficient for mass production as other traditional manufacturing processes, as only a limited number of products can be cast at a single time.

Thus for small quantity batch production and rapid prototyping, vacuum casting is a great manufacturing process, with efficient manufacturing and low cost of production.

It is a very versatile and highly adaptive manufacturing process. Hence, it is the preferred production process for custom and low volume project.

The applications of Vacuuming Casting

The Parts made by Vacuum Casting
The Parts made by Vacuum Casting


Consumer products such as sunglasses, pens, and other stationery products, cosmetic packages, combs and hair brushes are made more efficiently using vacuum casting.


Food and beverages packaging, food containers, bottles, cans, mugs, and glasses are made using vacuum casting.

As rapid manufacturing is a key aspect in these industries, vacuum casting is extensively used due to the quick manufacturing nature and high efficiency of the process.


Polyurethanes have excellent shock and heat resistance. Thus vacuum casting using polyurethanes is a preferred manufacturing process for making housings of electronic devices.

In addition, Vacuuming Casting can produce soft material parts that couldn’t be made by 3D printing and CNC prototyping. So, if your need soft parts such as PP, rubber to assemble, the only way you get the parts is by vacuuming casting.

How does vacuum casting work?

1. Master Model Building

First of all, producing vacuum casting prototypes require a high-quality master model with high dimensional accuracy. To ensure the final vacuum casting parts are the same as expected, creating flawless mater model is the vital foundation. Master model can be created by 3D Printing or CNC Machining, and dedicated post-processing, grinding, for instance, is necessary. These steps make sure that the master model is perfect to use. At our company, we will go through all details before making the master model, like design file checking to guarantee a manufacturable master model.

 vacuum casting, vacuum casting part, vacuum casting prototyping, silicone vacuum casting

2. Silicone Mold Making

Master model is ready to use. Then it’s time to pour liquid silicone into the casting box and fully immerse the master model. It takes several hours to cure the silicone naturally. After the mold is cured, cut open the mold and take the master model out of the mold. You will see a hollow space in the middle of the silicone mold, which fits the dimensions and specifications of the master model. Later on, the silicone mold needs to be cured again at a high temperature in an oven because the mold is still soft and sticky. Curing time would be based on size of the mold.

3. Parts Producing

The final step is casting parts with the silicone mold. Before casting, clean the surface of the silicone mold again is necessary. Then spraying the silicone mold internal structure with special release agents, attach tape to the edge, and even insert steel bars inside for large mold. All these steps make sure that mold release without damages. Casting materials mixture should be done in advance. Then fully fill the mold with materials, the process is done in a vacuum chamber for degassing, ensuring air bubbles are removed. Afterwards, move the parts in an oven for curing. Curing time is based on part size as well. The vacuum casting part can be removed from silicone mold after cool down.

 vacuum casting, vacuum casting part, vacuum casting prototyping, silicone vacuum casting

Benefits and drawbacks of Vacuum Casting


Vacuum casting is a highly efficient manufacturing process. Almost any Intricate and delicate shapes can be manufactured easily with high precision, and at a lower cost.

Some of the advantages of using vacuum casting for manufacturing are:

·   Complex and intricate shapes can be easily manufactured with high precision.

·   Multiple components can be simultaneously manufactured, increasing the efficiency of production.

·   Rapid prototyping using high-quality urethane is possible for small batch production

·   Different polyurethanes have different material properties. Hence a variety of products can be manufactured using different polyurethanes.

·   Material cost of polyurethane is low, hence manufacturing is highly economical.

·   Silicone molds are easier to manufacture than metal molds. Hence mold manufacturing can be efficiently done.


Although vacuum casting is a very efficient manufacturing process, like every other manufacturing process, it also has a few drawbacks.

·   In vacuum casting the molds are made of silicone and compared to injection molding, where the molds are made of metal, the lifespan of silicone is very less, so the life span is much shorter than injection molds

·   Every mold can produce about 30-50 times, compared with injection mold which can product for 500 thousands shot, the life span is too much shorter. The is why Vacuum casting is confined in prototyping not mass production. So vacuum casting is more suitable for low-volume production than mass production.

·  Need regular cleaning. That sounds a bit inconvenient, but we have to do that, because residue in the previous cast will affect the next cast.

·   Silicone molds are subjected to shrinkage due to thermal expansion. The shrinkage rate of commercial silicone is from 1% to 4%., compared with injection molds which is only less than 0.5%, so the precise of vacuum casting is harder to control than injection mold. With regard to the precise, it also up to the technology the manufacturer have, so finding a trustworthy prototyping to provide vacuum casting services for you is very important.

Our company provide a video to show how does vacuum casting works.