Silicone & Urethane Casting

We use silicone and urethane casting to quickly manufacture high-quality plastic cast parts in small to medium quantities (~10-1000) parts. With shorter lead times and lower tooling costs than injection molding, these rapid casting technologies offer a significantly lower unit cost than traditional injection molding at these volumes. In fact, silicone and urethane casting afford some of the lowest unit costs of any manufacturing technologies, including 3D printing.

Rapid cast plastic parts are durable and inexpensive. They are able to consistently produce surface details and offer high-quality finishes with the look and feel of consumer products. Because they are so much less expensive than injection molding for small to medium runs, silicone and urethane casting are ideal for prototyping and final products alike.

Urethane casting produces complex textures consistently and accurately, creating plastic parts with the look and feel of final products.

Get a Customized Quote in 24 Hours or Less

Request a quote with our Quick Quote tool or by giving us a call. A RapidMade engineer will review your design and send you a price in 24 hours or less. Once your order is placed, parts made with rapid casting have a typical lead time of 5-12 days.


Silicone & Urethane Casting Materials

Urethane and silicone molds can cast a range of materials, including elastomers and rigid plastics, as well as silicone, plaster and even concrete. Cast plastic parts can range from 20A - 90D on a durometer and come in food-safe and medical-grade options.

As a result, parts produced from silicone and urethane casting can fulfill a variety of purposes, from functional prototypes to consumer goods. Common applications for rapid casting include electronic housings, gaskets, cosmetic parts and displays. For more information on all of our materials, click here.

Plastic parts cast with a urethane mold and 3D printed tooling.

Rapid Tooling for Rapid Casting

Whenever applicable, we use 3D printing to create the master patterns for silicone and urethane mold-making, so you can have tooling in weeks, not months. We can easily reverse engineer existing objects with 3D scanning as well, allowing us to quickly create accurate models or durable, customizable replacements.

Once created, each mold can be used to cast thousands of parts with the look, feel and durability of finished products. Because they are relatively quick and inexpensive to produce, silicone and urethane molds are also a cost-effective option for iterating prototypes for cast or molded parts.

3D printed pattern for a rubber model of a crab is shown next to the silicone mold it produced.

Design Guidelines

Please note that these are are guidelines, not hard-and-fast rules. Follow these, and you should be in pretty good shape. We'll let you know if we see any problems with your design.

Casting is often more art than science. Please consult with our casting experts for project specific design instructions.

Parameter Inches Milimeters
Maximum Part Size Varies Varies
Minimum Supported Wall Thickness 0.080 2.00
Minimum Unsupported Wall Thickness 0.080 2.00
Minimum Supported Bosses 0.080 2.00
Minimum Unsupported Bosses 0.080 2.00
Minimum Embossed Detail (Height and Width) 0.040 1.0
Minimum Engraved Detail (Height and Width) 0.040 1.00