What is Cast Urethane?

The cast urethane process involves a 3D-printed or CNC machined master pattern that is an exact replica of the part you want to build. That pattern is then suspended in an enclosure and encased with silicone rubber to form a mold. After it is cured, the silicone mold is cut in half and the pattern is removed to reveal the mold cavity. Liquid polyurethane or silicone is then poured into the mold and it is placed in a pressurized or vacuum chamber. Once cured, your part is removed and the process can be repeated.

Senturi has an intimate network of best-in-class casters that specialize in a providing high-value, low-volume parts at a fraction of the cost of injection molding. Whether the parts are going to end up at a tradeshow or a validation lab, we will make sure they are flawless.

Urethane Casting Capabilities

Have a need for low-volume, high-quality plastic, rubber or silicone parts? Senturi’s cast urethane offerings are a great choice for low volumes (1 – 100s) so you can demonstrate aesthetic models to investors or validate production-representative parts before investing in hard tooling.

We cast Shore D and Shore A materials with desired properties such as tear resistance, high impact resistance, clear color, flame retardant properties and more.

Similar to our injection molding process, our team will send you first articles for your initial review before casting the remaining parts.

Project Guidelines
Min Part Size 1in x 1in x 1in
25.4mm x 25.4mm x 25.4mm
Max Part Size 36in x 36in x 36in
914mm x 914mm x 914mm
Standard Tolerances +/- 0.005 in per in
+/- 0.13 mm per in
Standard Lead Time 10 days to first articles
10-15 days for remaining balance


We cast both urethane and silicone parts. If you do not see the material you need, please reach out to our sales team to discuss specialty materials.

Shore D Materials:

  • ABS-like (80D)
  • PE-like (65D)
  • PC-like (84D)
  • PP-like (70D)
  • ABS-like, FDA Compliant (80D)
  • ABS-High Impact (78D)
  • ABS-High Impact, Flame Retardant (85D)
  • ABS-High Impact, Class IV, FDA Compliant (85D)
  • ABS-High Strength (85D)
  • ABS-High Strength, FDA Compliant (85D)
  • Nylon/Delrin-like (84D)
  • Hi Temp (84D)
  • Water Clear (80D)
  • PC-like, Haze Clear (84D)

Shore A Materials:

  • Standard Elastomers (15A-94A)
  • High Performance Elastomers (15A-90A)
  • Water Clear Elastomers (45A, 65A, 70A, 90A)
  • Silicones (15A, 25A, 35A, 40A, 42A, 50A, 53A, 60A, 75A)
  • Medical Silicone (38A)

Check out parts made of various materials in our parts gallery.


Have unique finishing requirements? Our network has an array of capabilities to make sure your parts are finished to meet all your cosmetic and performance requirements.

  • Color Matching
  • Painting
  • Texture Treatment
  • Satin Finish
  • Semi-Gloss Finish
  • Polishing
  • Part Marking
  • Light Assembly
  • Custom Finishes

Check out parts with various finishes in our parts gallery.

Frequently Asked Questions

How is urethane casting different than injection molding?

Although urethane casting is a very different process, it is important to recognize that it is similar to injection molding . In both processes, the material is fed into a mold cavity to produce the desired design. But there are far more differences that you can see below:

  • Cast urethane molds are built using a master pattern. The master pattern is typically a 3D-printed and encased in silicone. The silicone cures and the mold is cut into two and the pattern is removed to create the representative cavity. For injection molding, toolmakers cut both halves of the tool on a CNC machine per a model or engineering drawing.
  • Cast urethane utilizes soft tooling or molds made of silicone where injection molding utilizes hard tooling made of aluminum or steel. Soft tooling is faster and less expensive but has a far lower shot life compared to hard tooling.
  • Cast urethane usually utilizes a two-part liquid thermoset material (urethane or silicone). On the other hand, injection molding is utilizes thermoplastics that are heated, injected and cooled.
  • Cast urethane has more flexible design guard rails. Soft tooling can be manipulated during the demolding process to allow
I have no experience with casting. Can I still work with you?

Yes, absolutely. Our team will work with you to make sure your design is able to be casted. Soft tooling is advantageous because it is flexible so features like undercuts and draft angles are not as critical to consider because demolding is easier. But if injection molding is your ultimate goal, we can help make sure your design is suitable for both processes.

How long does soft tooling last?

The major disadvantage of soft tooling is its lifespan. Aluminum and steel tools last orders of magnitude longer. A typical silicone mold will allow for anywhere from 15 – 50 shots depending on the size, geometry and detail.

What inspection options are available?

When you start a project with us, we will make sure we understand your inspection needs. In our default inspection, QC will inspect against your drawing and we will provide you first articles for your own inspection and approval. We will not provide any documentation. If you need a dimensional report or First Article Inspection report, we can accomodate that in our custom inspection offerings.