3D printing (typical use)
- Best for single units or very small batches
- Material set depends on print process and vendor
- Surface and tolerance reflect layer or process limits
- Useful for internal fit experiments before steel is cut
Process comparison
Injection Molding vs 3D Printing: When Each Process Wins
3D printing excels at one offs and geometry experiments. Injection molding wins when the same design must ship repeatedly with stable material properties.
Two different jobs
Printing proves geometry; molding proves a production process
Teams often print first because it is fast for a single cavity worth of plastic. Molding enters when the question changes from can we build this shape to can we build thousands that match.
NetProto does not sell 3D printing. This page exists so you can decide when to stop iterating in printed plastic and quote a hardened steel tool instead.
If you still need loose tolerances and one off fit checks, printing may stay the right tool. If stakeholders need production grade resin and repeatability, molding is the honest comparison.
Side by side
How the processes differ in practice
Neither process replaces the other. The mistake is using printed parts to sign off a design that will only exist as molded production.
Injection molding with one steel tool
- Unit cost drops as quantity rises on the same tool
- Production grades and fillers match supplier datasheets
- Cosmetics and tolerance come from the mold, not post processing alone
- NetProto quotes tool and piece price together from CAD upload
Decision cues
Signals that molding should be next
Qualitative routing only. Upload CAD when you are ready for a steel tool quote.
| Question | Lean printing | Lean molding |
|---|---|---|
| Annual quantity | Dozens or less | Hundreds and up |
| Material requirement | Any printable resin is fine | Specific production grade |
| Surface for customer facing parts | Acceptable with finishing | Molded finish required |
| Same CAD for years of builds | Design still churning weekly | Design frozen enough to cut steel |
Ready for a tool quote
You are likely past printing when
If several items are true, get steel tool and unit pricing on one quote.
Stakeholders need the production resin, not a print only substitute
Cosmetic defects from layer lines would fail review
You are planning repeat builds across multiple purchase orders
DFM feedback should happen before metal is purchased, not after prints arrive
Continue exploring
Process comparisons
Return to the hub or open a related process guide.
Compare hub
All comparison guides.
Compare hubMaterials library
Resin guides after process is set.
Materials libraryInjection molding vs CNC
When plastic molding replaces machined prototypes.
Injection molding vs CNCFAQ
Common questions
Can I print mold inserts instead of steel?
Some programs experiment with printed cavities for very low volume work. NetProto compares against that path but delivers hardened steel tools built for the life of the part.
Does NetProto print prototypes before molding?
No. First shots come from the quoted steel tool after DFM review. If you still need printed fit models, keep that work separate from production approval.
What lead time applies to the steel tool?
Qualified programs typically see hardened steel tools completed in 10 business days depending on part size and complexity. That is tool build time, not first article delivery.
Next step
Quote the steel tool when printing stops answering the question
Upload CAD to see tool cost and piece price together. NetProto manufacturing is ISO 9001 certified.