Urethane casting
Production-quality parts in as fast as 10 days, no steel tooling to wait on. Silicone tools and cast urethanes for small-batch runs.
Engineer reviewed quote
Want to learn more? Read on.
Cast parts we ship.
Silicone tools and production like resins, matched to the durometer and finish the program needs.
Housing halves
Gray rigid urethane beside a translucent amber shot of the mating half.
Perforated panel
Blue rigid urethane with the hole pattern cast in, no drilling.
Bezel frame
Black rigid urethane with the stiffening ribs cast in.
Design guidelines
DFM considerations
Urethane casting, or RTV (Room Temperature Vulcanization), is an efficient way to produce low-volume parts with injection-molding-like quality. With much quicker lead times, it's well-suited for a variety of thermoplastics, rubbers, and resins. The soft tooling is quick to make but has a short lifetime. The process follows three main steps: first, we create a master pattern using 3D printing or CNC machining; second, we pour liquid silicone around the master to build the mold; finally, the resin is poured into the mold to produce a high-quality replica.
Wall thickness
The flexibility to design both thin and thick walls in the same part is tempting, but we recommend maintaining a consistent wall thickness of at least 1mm.
Bosses
Keep bosses at least 1mm in height and diameter with wall thickness no more than 60% of the nominal thickness to avoid sinkage.
Ribs
Add ribs to strengthen large flat areas and reduce warpage. Like injection molding, maintain a thickness under 60% of its mating wall and limit the rib height to 3x of its base thickness.
Undercuts
Undercut features are easy, with no inserts needed, but if your goal is moving to injection molding it's smart to design with the production process in mind from the start.
Material overview
Materials used in urethane casting process
Cast polyurethanes are two-part thermosets that cure at low pressure in silicone tools. Quick turnarounds, low capex, and resin properties that read close to production thermoplastics. Good for small-batch functional parts, design validation, or short production runs.
We blend additives per batch. Pick the mechanical, thermal, or cosmetic target (stiffness, heat resistance, clarity, Shore A softness) and we'll spec the resin.
Casting resins
Polyurethane resins that behave like common thermoplastics. Each one is matched to specific mechanical, thermal, and cosmetic needs.
UP-5690
Simulates
ABS
Type
Rigid
Impact resistance
Good
Heat resistance
Good
Surface finish
Standard
Use case
Functional prototypes
Reference
Material advisor
Match your target production resin to the closest urethane casting equivalent. Use these as a starting point, final selection depends on mechanical, thermal, and cosmetic requirements.
| Production material | Urethane equivalent |
|---|---|
| ABS | UP-5690, UPX-5210 |
| PP | UR-2180 |
| PMMA / PC | T-0387 |
| Silicone / TPE | T-8150 |
| PC | T-8263 |
| FR ABS | T-8400 |
| Nylon / POM | PX-223HT |
Think urethane casting might be the answer? Upload your CAD and an engineer will price it against molding and printing.
Get a QuoteTools we pour.
Silicone poured around a printed or machined master. Each tool gives 20 to 50 parts, and the master stays on the shelf for the next one.
Tray tool
Both halves open, the cast part still seated in one side.
Vent grille tool
Round grille cast with its louvers, the two tool halves side by side.
Ring tool
A black ring cast in a clear silicone block, ready to demold.
Options
Urethane casting options
01
Lead time
Master pattern and mold usually take 3 to 4 days to make, with parts turnaround in 7 to 14 days.
02
Painting
Glossy or matte, textured or soft-touch. We match mold textures and polish finishes per part, and add EMI shielding or clear coat when the part calls for it.
03
Assembly
Press-fit inserts, screws, pad printing, PCB assembly, and split and glue assemblies. No matter how small the task, we're on it.
04
Color options
Urethane cures milky white. We cast in your Pantone color, then add a final paint coat so scratches don't expose raw resin.
05
Longevity
Each silicone tool yields 20 to 50 parts. We keep the master pattern, so a fresh tool is quick to make when you need more.
06
Tolerances
±0.15 mm on small rigid parts out to ±0.50 mm on large flexible ones, angles ±1.5°, holes ±0.10 mm. Use it to settle fits and tolerance budgets before you commit to production tooling.
Quantities, finishes, tolerances.
No minimum. We cast single prototypes through runs of up to 200 parts. Each silicone mold gets 20 to 50 parts, and we make new molds from the same master pattern.
Casting uses silicone molds instead of steel, tooling cost is 90 to 95% lower and lead time is 70% shorter, but per-part cost is higher. Casting covers runs up to about 200 parts. Past that, a prototype injection mold usually wins, and we quote both when a program sits near the line.
Finish replicates the master pattern. SLA masters give you smooth, paint-ready surfaces. CNC masters can replicate specific textures. Parts can be painted to any Pantone/RAL spec.
Yes. We have UL94 V0-rated polyurethane resins for flame-retardant applications. Material certs and test reports provided.
Linear tolerance runs ±0.15 mm on small rigid parts up to ±0.50 mm on large flexible ones, scaling with size: rigid resins hold ±0.15/±0.20/±0.28/±0.35/±0.45 mm across the 0–50, 50–100, 100–200, 200–300 and 300 mm-plus bands, and flexible resins ±0.25/±0.30/±0.35/±0.40/±0.50 mm. Angles hold ±1.5° and holes ±0.10 mm. Shore A hardness tolerance is ±10A for rubber-like resins. Tighter tolerances possible with post-machining on critical features.
Each mold gets 20 to 50 parts depending on geometry and resin. New molds are made from the same master pattern at the same quality. Mold life is already factored into per-part pricing.
Yes. Threaded inserts, bushings, magnets, and other hardware can be cast in or heat-staked after. Insert placement is documented in the mold setup.
STEP (.stp) and IGES (.igs) preferred. 2D drawings in PDF for tolerances, finish, and color callouts. SolidWorks, Creo, and NX files also accepted.
Next step
Let's move your part forward.
Send the CAD. An engineer replies in 1 to 2 business days.
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