What is Urethane Casting?

Urethane casting uses silicone moulds to produce plastic and rubber components using two-component polyurethane resins under a vacuum. Also known as vacuum casting or polyurethane casting, it is a versatile manufacturing technology capable of producing complicated engineering parts in polyurethane resins and cast nylon by simulating injection moulding.

Fast and Efficient Vacuum Casting Services

Vacuum casting is the right manufacturing technique for your project. Although there are multiple steps involved in the process, it is easy and straightforward. Prototypes are done in a matter of days and not weeks. The vacuum casting process involves three steps: creating the master pattern, producing the mold, and casting copies.

Step 1. Creating the Master Patterns

The vacuum casting process begins with creating the master model. It’s made by converting the CAD files into 3D representation using CNC machining or 3D printing like SLA or SLS. If our customers prefer to supply their patterns, we at Top rapid prototype would gladly accommodate it. These patterns, however, should be able to withstand 40 degrees temperature.

Step 2. Making the Mold

Creating the mold is done using liquid silicone. The silicone material is injected in the casting box with the master pattern inside. The main idea is for the casting material to surround the master pattern and create an impression. It is cured in an oven for more than 16 hours.

Once the curing process is completed, the mold is cut open and the master pattern removed. What is left is an empty cavity with the shape of the master pattern.

Step 3. Producing Copies

The last step in vacuum casting is creating copies. In this step, the resin is poured into the empty copy to make a replica of the original. It allows for two or more resins to manufacture prototypes and the silicon mold can make 20 or more copies from the master model.

The difference between vacuum casting and other techniques is the vacuum casted parts are high-quality. It renders the parts suitable as a series of final components in small quantities, for function testing, and marketing purposes. It can produce parts without air packets that could compromise its integrity.

Vacuum Casting Tolerances

Top rapid prototype ofers a range of vacuum casting tolerances to meet your custom requirements Based on the master pattern and part geometry, we canreach dimensional tolerances between 0.2 - 0 4 m. Below are the technical specifications for our vacuum casting services.

Type	Information
Accuracy	Highest precision to reach +0.05 mm
Max Part Size	+/- 0.025 mm +- 0.001inch
Minimum wall thickness	1.5mm ~ 2.5mm
Quantities	20-25 copies per mold
Color & Finishing	Color and texture can be customized
Typical Lead Time	Up to 20 parts in 15 days or less

Benefits of Using Vacuum Casting

High Precision – The silicon mold is faithful to the master pattern. Vacuum casting has high fidelity, with the intricate details translated into the finished part.

High-Quality Parts – The wide range of resins available for vacuum casting use allows you to choose the right material for the design with the right amount of hardness: rigid or flexible and final appearance. You can have the finished part with colors and the right transparency. You can also create over moldings or have painted finishes.

Saves Time and Cost – Using silicone, an affordable mold makes lower the price compared to other forms of tooling. It is more valuable than 3D printing because you can make ten parts. On top of it all, it only takes 7 to 10 days to complete around 50 parts.