Material-Behavior Selection
Selected castable urethane systems can be specified around target rigidity, flexibility, clarity, color, and application requirements. Final material selection is reviewed against the intended part function.
Short-Run Polyurethane Parts
Urethane Casting
Services
GD Prototyping delivers production-like urethane parts in selected rigid, flexible, clear, or color-matched polyurethane systems for validation and short-run production.
Process Overview
What Is Urethane Casting?
Urethane casting, also called urethane molding, produces cast polyurethane parts by pouring a selected liquid polyurethane system into a silicone mold made from an approved master pattern.
The process is used when teams need several production-like parts without investing in hard tooling. Material, color, surface finish, inserts, and critical fit requirements are defined before polyurethane casting begins.
Why Urethane Casting
Key Benefits of
Urethane Casting?
Urethane casting is suitable when a project needs production-like material behavior and controlled visual finishes while quantities remain below the point where hard tooling is justified.
Appearance & Surface Direction
The approved master pattern establishes the starting surface condition. Gloss, texture, painting, polishing, and color requirements are planned before production begins.
Short-Run Quantity Planning
Polyurethane vacuum casting provides a soft-tooling route for multiple parts when project quantities do not justify hard injection molding tooling. Batch size and mold count are planned around project demand.
Production Decision Support
Use cast urethane parts for fit checks, functional evaluation, customer review, pilot builds, and early market samples before final tooling decisions are made.
Silicone Mold Making Capabilities
Urethane Part Production
SLA prints provide fine detail and smooth surfaces for accurate silicone mold master patterns.
- Fine surface detail
- Smooth master finish
- Complex geometry
- Rapid pattern turnaround
Fine surface detailMaterial & Finish Selection
Select polyurethane grades, colors, textures, and finish targets to match functional and visual project requirements.
- Stable reference datums
- Controlled dimensions
- Durable tooling surface
- Repeatable mold results
Customer-Supplied Pattern
Existing patterns can be reviewed and used when geometry, surface condition, and moldability meet project requirements.
Example component for pattern review; not a customer-supplied pattern record.
- Pattern condition review
- Moldability assessment
- Parting and gate planning
- Repeatable casting setup
| Pattern Source | Advantages | Considerations |
|---|---|---|
| SLA 3D Printing |
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| CNC Machining |
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| Customer-Supplied Pattern |
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How It Works
How Urethane Casting Works
CAD & Requirement Review
We review CAD files, quantity, target material behavior, color, finish, critical dimensions, inserts, and appearance requirements.
Mold & Casting Plan
The project plan confirms the master-pattern route, silicone mold strategy, parting line, gates, vents, material system, and inspection priorities.
Material Preparation & Urethane Pouring
Selected polyurethane components are prepared according to the approved material system and poured into the silicone mold. Controlled casting conditions support fill and surface requirements.
Curing, Demolding & Trimming
After curing, cast urethane parts are removed from the mold. Gates and flash are trimmed with attention to specified interfaces and visible surfaces.
Finishing & Assembly
Painting, color matching, polishing, texture work, threaded inserts, bonding, or assembly are completed according to the approved project scope.
Inspection & Delivery
Finished urethane parts are reviewed against agreed dimensional, visual, quantity, and packaging requirements before delivery.
Urethane Casting Materials
Metals
-
Non-Metals
A rigid polyurethane casting resin for housings, covers, and functional prototypes with ABS-like behavior. It is not ABS thermoplastic.
Two-part polyurethane casting resinConfirm stiffness, impact behavior, color, and the selected formulation.
Appearance, Color & Material Simulation
Realistic Parts.
Endless Possibilities.
Urethane casting combines selected castable urethane systems with an approved master-pattern finish, helping teams evaluate material feel, color, translucency, and surface character before hard tooling.
- Custom Color DirectionProvide a Pantone code, sample, or approved visual target.
- Material Behavior SelectionChoose rigid, flexible, clear, or specialty polyurethane by function.
- Surface Finish DefinitionSpecify gloss, texture, paint, polish, and cosmetic requirements.
Material Types
- Rigid PolyurethaneShore D 60–85
- Flexible PolyurethaneShore A 30–90
- Clear / Translucent PolyurethaneShore D 70–80
- High-Temperature PolyurethaneShore D 80–90 · Up to 120°C
Color Options
Pantone matching, custom colors, and clear options.
Transparency
Clear · Translucent · Frosted · Opaque
Texture Options
Gloss · Satin · Matte · Fine texture
ⓘ Color chips, material swatches, and finish references can be reviewed before production when a project requires a defined visual target.
Technical Capability
Urethane Casting
Capabilities
Defined parameters for low-volume polyurethane parts. Final requirements are reviewed against the approved drawing, resin grade, and finish target.
| Dimensional Tolerance | ±0.3 mm or ±0.3%, whichever is greater. |
|---|---|
| Surface Detail | ≥0.5 mm for raised or recessed details, logos, and texture features. |
| Minimum Feature Size | Ø1.0 mm holes; 0.5 mm grooves or ribs, subject to demolding direction. |
| Minimum Wall Thickness | 0.75 mm minimum; 1.5 mm recommended for stable filling and dimensional control. |
| Maximum Part Size | Up to 2,000 × 1,200 × 1,000 mm. |
| Surface Condition | Ra 1.6–3.2 μm as cast; down to Ra 0.8 μm after polishing. |
| Recommended Quantity | 1–100 parts per batch; typically 15–25 parts per silicone mold. |
| Typical Lead Time | 5–10 business days after CAD, material, color, and finish approval. |
Design Notes
Urethane Casting Design Guidelines
Wall Thickness
Keep walls as uniform as possible. Use 1.5–4 mm where practical; local sections down to 0.75 mm require engineering review.
1.5–4 mm WallsDraft & Demolding
Use 1–2° draft on vertical walls where possible to support clean demolding and protect cosmetic surfaces.
1–2° DraftUndercuts
Silicone molds can release many undercuts, but deep or complex features need a mold-split review.
Mold Split ReviewInserts & Threads
Identify threaded inserts, bosses, and load-bearing interfaces early so placement and post-processing can be planned.
Threaded InsertsCritical Fits
Mark critical dimensions and mating interfaces on the drawing to account for casting shrinkage, finish thickness, and tolerance stack-up.
Critical DimensionsParting Lines
Place parting lines away from visible faces and sealing surfaces whenever geometry allows.
Parting Line PlanningCosmetic Surfaces
Define visible faces, gloss level, texture, and paint requirements before master-pattern finishing begins.
Cosmetic SurfacesColor Matching
Provide a Pantone reference, physical sample, or approved visual target for project-specific color review.
Pantone Color MatchingPart Size & Stability
Large, thin, or asymmetric urethane parts require review for fill behavior, shrinkage, and dimensional stability.
Large-Part ReviewUrethane Cast Part Features
Typical Urethane
Cast Parts
Cast urethane parts combine cosmetic surfaces, functional interfaces, and tailored material behavior for validation builds and low-volume production.
Applications
Urethane Casting Applications
Automotive
Custom automotive parts for prototypes and low-volume production.
Automation
Custom robotic parts, fixtures, and automation equipment components.
Aerospace
Aerospace prototypes and custom parts for engineering evaluation.
Medical
Medical device prototypes, custom housings, and mechanical components.
Energy
Custom energy equipment parts, housings, and mounting components.
Semiconductor
Custom semiconductor equipment parts, fixtures, and handling components.
Office Equipment
Custom parts and prototypes for printers, copiers, and scanners.
Electronic Appliances
Custom appliance parts and enclosures for product development.
Quality Control
Urethane Cast Part
Review Before Delivery
Each order is reviewed against approved CAD, material, color, finish, and project-specific inspection requirements before shipment.
- CAD & Moldability Review
- Material & Color Verification
- Parting Line & Flash Inspection
- Key Dimension Measurement
- Cosmetic Surface Inspection
- Inserts & Assembly Check
- Quantity & Packaging Verification
- Inspection Records on Request
Process Selection
Urethane Casting vs.
Injection Molding
| Selection Factor | Urethane Casting | Injection Molding |
|---|---|---|
| Volume & Unit Economics | Best suited to 1–100 parts. Silicone molds typically yield 15–25 parts each; tooling cost is low, while unit cost rises with quantity. | Suited to repeat production from hundreds of parts upward. Higher tooling cost can be offset by lower unit cost as volume increases. |
| Tooling & Launch Time | Uses a silicone mold made from an SLA or CNC master pattern, avoiding the need for a machined metal tool. | Uses aluminum or steel tooling with gates, cooling, and ejection systems; tool manufacture and validation require more preparation. |
| Material Choice | Uses castable polyurethane systems that simulate ABS, PC, PP, rubber, clear, and other production-material behaviors. | Uses specified production-grade thermoplastics, engineering polymers, filled grades, and regulated material options. |
| Design Changes | A design revision usually requires an updated master pattern and silicone mold, making iteration practical for short runs. | A design revision may require tool re-machining, inserts, or replacement tooling after mold production begins. |
| Finish & Appearance | Replicates the master-pattern surface and supports color matching, textures, painting, polishing, and soft-touch effects. | Delivers repeatable color, texture, gloss, and surface finish after the tool and molding process are validated. |
| Accuracy & Repeatability | Typical tolerance is ±0.3 mm or ±0.3%, whichever is greater. Results are influenced by master accuracy, resin shrinkage, and mold wear. | Supports stronger long-run repeatability when tooling, resin, process settings, and inspection requirements are controlled. |
| Selection Guidance | Choose for functional prototypes, appearance models, market samples, and low-volume parts while design or demand is still evolving. | Choose when the design, resin specification, and demand forecast are stable enough to justify production tooling. |
Still deciding between urethane casting and injection molding? Talk to an Engineer for a quantity, material, and design review.
FAQ
Urethane Casting FAQ
What is urethane casting best used for?
Urethane casting is used for production-like prototypes, appearance models, functional testing, and low-volume parts.
How many parts can one silicone mold produce?
A silicone mold typically produces 15–25 urethane cast parts, depending on geometry, resin, and finish requirements.
What tolerance can urethane casting achieve?
Typical tolerance is ±0.3 mm or ±0.3%, whichever is greater.
What materials and finishes are available?
Rigid, flexible, clear, and high-temperature polyurethane options are available with custom colors, textures, painting, and polishing.
When should I choose urethane casting over injection molding?
Choose urethane casting for 1–100 parts or evolving designs; choose injection molding when volume and material requirements are stable.
Ready to Start Your
Urethane Casting Project?
Upload your CAD files for an engineering review and a project-specific quotation.
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- Engineering Review
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Confidential File Handling
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