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Urethane Casting Services
Low Volume, Durable Parts with Production-Level Quality
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Urethane Casting
Urethane casting provides end-use, rigid plastic parts or rubber parts with production-level quality. Built without expensive and time-consuming hard tooling, our urethane casting process uses a 3D printed master pattern and silicone molds to deliver high-quality, short-run parts up to 30” long. The finished dimensions of urethane cast parts depend on the accuracy of the master model, part geometry, and casting material. In general, a shrinkage rate of + 0.15% is expected.
Cast urethane parts are frequently used when color, surface quality, and toughness are required. Cast urethane is a perfect alternative for insert molding or overmolding in low volumes with diverse material choices. Urethane cast parts can also be color-matched, painted (including EMI shielding), have installed inserts, and even custom finished.
Urethane Casting Materials
- Flexible Urethane (Shore D 62-67)
- Rigid Urethane (Shore D 82-86)
- Rigid Urethane (Shore D 62-67)
- Custom material to match your requirements
Available Finishes for Urethane Casted Parts
Standard
Parts are built with a smooth, high-quality surface finish and your choice of color.
Custom
Xometry can provide additional processing, including custom texture and insert installation, to meet your needs.
Ready to get started on your urethane casting quote?
Applications of Urethane Casting
Low-Volume Production
Urethane cast parts are perfect for low-quantity production—when volumes do not justify investment in injection mold tooling—as well as for first run production parts, which can be completed weeks before production tooling is ready.
Advanced Prototyping
The urethane casting process and relatively inexpensive tooling involved makes it easy and economical to make any necessary design changes. Additionally, different materials can be used with the same mold, making it possible to test designs with a variety of materials.
Market Testing
End-user functionality and a high-quality finish makes urethane cast parts ideal for consumer testing, user evaluation and concept models. Using the cast urethane process means that changes can be incorporated quickly for either further testing or market launch.
Advantages of Urethane Casting
Urethane casting has a low-cost and quick turnaround for high-quality plastic parts compared to that of injection molding or 3D printing. Where injection molding requires expensive up-front investment for the machining of the mold, urethane casting's silicone mold, or "soft tooling," is relatively inexpensive and easy to produce off the master pattern. Where most 3D printing processes require extensive post-processing to get to a near-finished state, a urethane cast part comes out of the mold ready to go with just a few minutes of clean up. Urethane casting is the go-to solution when looking to do on-demand prototyping or low-volume production of rigid, flexible, clear, colored, or even rubber-like plastic parts. It's truly a jack of all trades process.
Overview: What is Urethane Casting?
The Basics Of Urethane Casting
Urethane casting provides end-use, rigid, flexible, and rubber parts with production-level quality. The urethane casting process uses a 3D-printed master pattern to create a silicone mold that delivers high-quality, short-run parts as an economical alternative to low volume injection molding.
How Urethane Casting Works
Urethane casting is similar to injection molding in that it requires a tool with a cavity in the shape of the final part. The major difference is that urethane casting uses a "soft" mold made of silicone whereas injection molding using a "hard" metal mold that has been CNC machined. The drawback to urethane casting, then, is that the mold wears out more quickly. However, it is vastly more cost-efficient for low-volume and prototype plastic parts with production-level quality and surface finishes.
The urethane casting process has 3 major steps:
- The Master Pattern: In step one, a master pattern of the final part is made using an additive manufacturing process. Polyjet 3D or stereolithography (SLA) 3D printing processes are most often used due to the high-resolution and naturally smooth finish to the prints. The master pattern is typically hand finished to achieve good surface detail before the creation of the mold tool.
- Molding: In step two, the 3D printed master pattern is encased in liquid silicone that cures around the pattern, with the silicone encapsulating all the features of the printed parts. When the mold cures, it is cut into distinct halves and the master pattern is removed. This leaves an internal cavity perfectly shaped like the part.
- Pouring: In the final step of the urethane casting process, a compounded urethane or silicone material is poured into the silicone mold, and the mold is then placed in a chamber, which helps remove air bubbles in the liquid material. For opaque parts, the chamber is typically pressurized. For clear parts, the chamber typically pulls a vacuum to mitigate any bubbles and increase clarity. Once cured, the silicone halves are separated and the newly formed part is removed. This process is repeated until the desired quantity is achieved.
Benefits Of Urethane Casting
Urethane casting has a low-cost and quick turnaround for high-quality plastic parts compared to that of injection molding or 3D printing. Where injection molding requires expensive up-front investment for the machining of the mold, urethane casting's silicone mold is inexpensive and easy to produce off the master pattern. Where most 3D printing processes require extensive post-processing to get to a near-finished state, a urethane cast part comes out of the mold ready to go with just a few minutes of clean up. Urethane casting is the go-to solution when looking to do on-demand prototyping or low-volume production of rigid, flexible, clear, colored, or even rubber-like plastic parts. It's truly a jack of all trades process.
Urethane Casting Tolerances
Typically Cast Urethane Part Tolerances
| Description | Tolerance Notes |
|---|---|
| Distance Dimensions | +/- 0.010” or +/- 0.003” per inch, whichever is larger, is typical. Irregular or overly-thick geometries may cause deviances or deflection due to shrinkage. |
| Shrink Mitigation | A shrinkage rate of +0.15% can be expected due to thermal expansion of the liquid, and the response of the flexible mold. |
| Surface Quality | Surface finish is externally smoothed to a satin or matte surface. Grow lines may be present on internal or difficult-to-access features. Polishing or custom finishes must be clearly defined and agreed upon at the point of order. |
| Feature Definition | Sharp corners and text may appear slightly rounded. |
| Size Recommendation | We can offer urethane cast parts as large as 30” long. |
This table is based on the assumption that designs have an adequate draft, radii, and coring for manufacturability. Please check out Xometry's Manufacturing Standards for more information on tolerances per process.
Why Choose Xometry for Urethane Casting?
Endless Options
Choose from millions of possible combinations of materials, finishes, tolerances, markings, and certifications for your order.
Easy to Use
Get your parts delivered right to your door without the hassle of sourcing, project management, logistics, or shipping.
Vetted Network
Only the top 6% of shops that apply to become Partners make it through our multi-tiered qualification process, so you can be confident your part will be made right.
