Urethane Casting

Urethane casting is a method used to create high-quality plastic parts, prototypes, and models. It is a cost-effective and efficient way to produce small batches of parts that are identical to the original design.

The urethane casting process involves pouring liquid polyurethane into a silicone mold. The mold is created from a master pattern, which can be made from a 3D printed model, a CNC machined part, or even a hand-carved sculpture. Once the mold is filled, the polyurethane is left to cure and harden. When the part is removed from the mold, it is trimmed and finished to meet the desired specifications.

The Urethane Casting: Step by Step

Create the master pattern

The first step is to create the master pattern using a 3D printer or other manufacturing method. The master pattern should be made of a material that can withstand the heat and pressure of the process of making a silicone mold.

Fabricate the silicone mold

To create the silicone mold, first prepare a flat surface and place the master pattern on it. Secure the master pattern in place using clay or other soft material. Then, mix the silicone in a clean container according to the manufacturer’s instructions. Pour the mixed silicone over the master pattern, making sure it completely covers the pattern. To avoid any bubble, the pouring can be done in a vacuum chamber.

Allow the silicone to cure

Let the silicone cure according to the manufacturer’s instructions. This usually takes a few hours.

Remove the master pattern

Once the silicone is fully cured, remove the master pattern by gently pulling it out of the silicone mold.

Prepare the mold for casting

Clean and prepare the silicone mold for casting by applying a release agent to prevent the urethane from sticking to the mold.

Mix the urethane

Mix the two-part urethane resin according to the manufacturer’s instructions.

Cast the urethane

Pour the mixed urethane into the mold, making sure to avoid introducing air bubbles. You can use a vacuum chamber to help remove any air bubbles in the urethane. That is why urethane casting is also called vacuum casting.

Allow the urethane to cure

Leave the mold undisturbed for the recommended curing time.

Remove the part

After the urethane has fully cured, remove the part from the mold. Trim or finish the part as needed.

Reuse or modify the mold

The silicone mold can be reused to create additional parts. If any modifications to the part are required, modify the master pattern and create a new silicone mold. A silicone mold can be used 12~15 times before it becomes too hard and brittle due to the chemical reaction between the polyurethane material and the mold material.

The urethane casting can produce part with character very like some thermoplastics, for example ABS, PC and more. Take ABS as an example. To create an ABS-like material using urethane casting, often a two-part polyurethane system is used. This system typically includes a base material and a hardener or curing agent. In order to simulate the properties of ABS thermoplastic, the base material may include additives such as fillers, pigments, or other chemicals that modify the material’s physical properties, including its rigidity, flexibility, and impact resistance. By adjusting the composition of the base material and the hardener, it’s possible to closely replicate the properties of ABS thermoplastic and achieve an ABS-like material using urethane casting.

Advantages of Urethane Casting


Urethane casting is generally more cost-effective than other manufacturing processes like injection molding, especially for small to medium production runs. It requires less expensive tooling, setup, and production equipment.


Urethane casting can be used to create parts with a wide range of shapes, sizes, and textures, and can also simulate the properties of different materials such as ABS, polycarbonate, or silicone.

Rapid prototyping

With urethane casting, you can quickly produce prototype parts for testing and evaluation, allowing you to refine and improve your design before committing to more expensive production methods.

High-quality surface finish

Urethane cast parts usually have a smooth and consistent surface finish, making them ideal for end-use parts, visual models, and display pieces.

Wide selection of materials

There are many different types of urethane materials to choose from, each with unique mechanical, thermal, and chemical properties. This allows you to select the right material for the specific application.

Low-risk production

Since the tooling and equipment costs are lower, there’s less risk involved in producing small to medium production runs, which can be especially beneficial for start-ups or new product launches.

CapableMachining Vacuum Casting Materials

Material Color Temperature resistance Paintable Feature
ABS-likeNaturally white and multi colors are available as required.40-50℃YGood Hardness
Nylon GF-likeBlack120℃YGood Strength
POM-likeNaturally white and multi colors are available as required.40-50℃YGood Hardness
TPU-likeColor can be adjusted as required100℃YShore Hardness40-90
Silicone Rubber-likeColor can be adjusted as required100℃YShore Hardness40-90

Take your product ideas to the next level with CapableMachining’s urethane casting service!

Our team of experts specializes in producing high-quality plastic parts and prototypes using state-of-the-art equipment and cutting-edge techniques. We offer a wide selection of urethane materials to choose from, each with unique properties to match your specific application. And with our quick turnaround times, low tooling costs, and ability to produce small to medium production runs, you can bring your products to market faster and more cost-effectively than ever before. Don’t settle for less – click the button below for all your urethane casting needs!

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