Bridge Production
Urethane casting turns a master pattern into production-like parts in days—not the weeks or months a full injection mold program can require. Use it to validate fit, function, and market response before scaling into high-volume molding.
What urethane casting is
Urethane casting uses a master pattern to create a silicone mold, then casts urethane resin into that cavity for repeatable short-run output.
The process starts with a master pattern—often from precision 3D printing or CNC machining—that defines the part geometry. A silicone mold captures that detail, then urethane resins are cast to produce parts with smooth surfaces, flexible or rigid mechanical properties, and enough consistency for functional testing or pilot builds.
For many teams, urethane casting is the practical middle ground between one-off prototypes and injection molding commitment. It supports bridge quantities, design iteration, and stakeholder demos while you still learn what the production tool must solve.
Process Decision
Neither process replaces the other. The question is whether you need speed and flexibility now, or unit economics and repeatability at scale.
Typical programs
These are the programs NetProto most often routes through casting before a molding launch.
Produce customer-facing samples or field-test units while injection mold design is still being finalized.
Test snap fits, seals, ergonomics, and assembly behavior with materials closer to end-use intent than early printed prototypes.
Cover launch quantities or supply gaps while production tooling, cavitation, or PPAP-style readiness is still in progress.
Design for silicone molds
Keep wall thickness as uniform as practical to reduce warping and uneven cure
Apply draft so parts release cleanly from flexible silicone cavities
Limit deep undercuts or plan removable mold sections where geometry requires them
Specify whether the part needs rigid, elastomeric, clear, or color-matched urethane behavior
Identify cosmetic surfaces separately from functional mating or sealing zones
Casting workflow
Build an accurate pattern through high-resolution 3D printing or CNC so the silicone mold captures true part detail.
Produce a mold suited to the expected casting quantity, material choice, and required surface quality.
Select rigid, flexible, or specialty urethane grades and cast the quantity needed for validation or bridge use.
Apply texture or post-cast finishing if needed, then use the learning to refine CAD before injection mold release.
Urethane casting FAQ
It depends on geometry, material, and cosmetic requirements. Silicone molds are best for short-run and bridge quantities—not long-life production cavitation. NetProto can align expected mold life with your quantity plan during quoting.
Programs can target rigid housings, elastomeric grips, clear or tinted parts, and color-matched appearances. Share functional targets—flex, hardness, temperature, clarity—so the resin shortlist matches the application.
Cast parts are excellent for fit, function, and appearance validation, but they are not a substitute for final production material and process qualification. Use casting to de-risk design decisions before steel tooling.
Once design changes slow down, forecast volume supports tooling investment, and the team needs production-grade repeatability and unit cost. NetProto can help connect the bridge program to the molding quote path.
Next Step
Upload CAD to review casting fit, or compare the injection molding path if your volume and timeline already justify production tooling.
