A 3D printed injection mold can go from CAD file to molded parts in days, for a small fraction of the cost of a metal mold. The parts are real injection molded parts in real production plastic. The trade-off is mold life: a printed mold makes dozens to a few hundred parts, not tens of thousands. For prototypes, pilot runs and bridge production, that trade is often a great deal.
The numbers
| Mold type | Typical cost | Lead time to parts | Typical mold life |
|---|---|---|---|
| 3D printed (resin) | From about $100 for simple molds | 1 to 3 days | Dozens to about 100+ shots, depending on plastic and shape |
| Machined aluminum | About $1,500 to $5,000 | 3 to 4 weeks | Thousands to 10,000+ shots |
| Hardened steel | About $5,000 to $100,000 | 4 to 8 weeks | Hundreds of thousands of shots |
Ranges from Formlabs and Protolabs. Real costs depend on part size and complexity.
Why many printed molds can still beat one metal mold
Printed molds wear out, but they are inexpensive and fast to replace. For a simple part, printing 20 molds at around $150 each is about $3,000, still well below most steel molds, and it gets you parts weeks sooner. Because each mold is inexpensive, you can also run several at once: rotate molds so one cools while another fills, or run them on more than one machine. And when the design changes, you print a new mold instead of re-cutting metal.
Part quality
- Same plastic as production. Parts are molded in polypropylene, polyethylene, TPE, ABS and similar plastics, not printed plastic.
- Surface finish can be close to production when the mold is printed at fine resolution and polished.
- Tolerances are looser than a machined metal mold, and fine features soften as the mold wears.
- Cycle times are longer, because plastic molds don't shed heat like metal.
Where printed molds work best
- Small to medium parts with generous draft angles.
- Lower-temperature plastics like PP, PE and TPE.
- Prototypes in the final material, pilot runs, and bridge production while a metal tool is being made.
Where metal is still the answer
- Runs in the many thousands.
- High-temperature or glass-filled engineering plastics.
- Very tight tolerances or large parts.
Talk to us
OnePiecePrints is building printed-mold tooling into our shop in Olalla, WA. If you have a part that's stuck between "too many to print" and "too few to justify steel," tell us about it. Related: 3D printing vs injection molding break-even · resin printing