Urethane casting (typical)
- Low volume without cutting steel
- Material approximates production plastic but is not identical
- Manual process with batch variation
Process comparison
Injection Molding vs Urethane Casting: Prototype Lookalikes vs Production Plastic
Urethane casting clones geometry in small batches without steel. Injection molding delivers production grade resin from a hardened steel tool.
Process choice
Silicone mold copies versus steel production
Cast urethane parts help marketing samples and fit checks. They are not a substitute for validating production resin, shrink, and gate cosmetics.
NetProto does not sell urethane casting. Use this page to time the jump to steel.
When stakeholders sign off cast parts, confirm the production resin and tool will be quoted separately.
Side by side
What each process proves
Cast parts prove shape. Molded parts prove shape, material, and process window together.
Injection molding (NetProto)
- Production resin from a hardened steel tool
- Stable cycle and cosmetics for repeating orders
- DFM tied to the same tool you will run in production
Routing table
When casting should give way to molding
Qualitative only.
| Factor | Casting can suffice | Quote molding |
|---|---|---|
| Quantity | Under roughly fifty for show parts | Production POs or repeating SKUs |
| Material sign off | Approximate look and feel | Must match UL or FDA listed grade |
| Cosmetics | Paint hides minor defects | Molded texture or clear surface required |
| Timeline | Need parts before steel is ready | Can wait for tool on qualified programs |
Before production quote
Confirm casting is not standing in for approval
Upload CAD when these are true.
Final resin grade selected in the materials library
Draft and texture frozen enough for steel
Test plan calls for molded resin, not cast duplicates
Stakeholders accept tool investment for unit cost drop
Continue exploring
Related guides
Process first, then resin.
Compare hub
All comparison guides.
Compare hubMaterials library
Resin selection after process is decided.
Materials libraryInjection molding vs CNC machining
When metal or low volume CNC still fits.
Injection molding vs CNC machiningFAQ
Common questions
Can cast parts use the same color as production?
Color can be close but not identical to molded in color production. Sign off molded chips when color is critical.
Next step
Move to steel when cast parts become the bottleneck
Instant quote covers tool and piece price together. NetProto manufacturing is ISO 9001 certified.