RICREO · Updated
The short answer
For a medium-size plastic part, FDM 3D printing usually pays off from a few dozen to a few thousand units. Injection molding has the lowest unit cost, but only after paying off a mold worth thousands of euros and weeks of lead time.
There is no threshold that fits every part. Geometry, material and the number of revisions move it by hundreds of units, so the sum is worth doing on the real part.
How to calculate the break-even point
Break-even quantity = mold cost ÷ (FDM part price − molded part price). Below that quantity 3D printing costs less in total; above it the mold wins.
Example: a €5,000 mold, an €8 FDM part and a €1 molded part. The difference is €7 per part, so 5,000 ÷ 7 ≈ 714. Up to 714 parts FDM wins; from 715 the mold does.
| Parts | FDM 3D printing total | Mold + parts total | Cheaper |
|---|---|---|---|
| 100 | €800 | €5,100 | FDM 3D printing |
| 500 | €4,000 | €5,500 | FDM 3D printing |
| 714 | €5,712 | €5,714 | FDM 3D printing |
| 715 | €5,720 | €5,715 | Injection molding |
| 1,000 | €8,000 | €6,000 | Injection molding |
What moves the threshold
The break-even moves as soon as one of the three numbers in the formula changes. These are the factors that move it most.
- Mold complexity: undercuts, slides and multiple cavities raise the cost and push the threshold up.
- Part size: in FDM the price follows volume and machine time, so large solid parts lower the threshold.
- Design revisions: every mold change costs money, while in FDM a revision is just a new file.
- Variants: several versions of the same part need more molds or inserts; in FDM only more files.
- Time and stock: a mold takes weeks and minimum runs, while FDM starts in 24–48 hours on standard materials and makes only the parts you need.
When to choose serial 3D printing
FDM is the right choice when the yearly quantity is below the threshold or still uncertain.
- Batches from 10 to a few thousand parts, including repeat orders.
- New products whose design will change after the first feedback.
- Spares and machine components produced on demand.
- Geometry with internal channels and light weighting that a mold would complicate.
When the mold is worth it
Injection molding remains the best choice for high, stable quantities, small and simple parts, a frozen design and molded surface finishes. In those cases we tell you: we work in FDM only and it makes no sense to push it past the threshold.
Pre-series: use both
Many companies use 3D printing as a bridge batch. While the mold is being built, an FDM batch gets the part onto the line or the market and lets you fix the design before it is locked into steel.
How we assess it on your part
Send us the STL, 3MF or STEP file, the yearly quantity and the material. The quote tool prices the part from its geometry; for batches from 100 parts we prepare a custom price and, if you ask, a comparison with the estimated mold cost.
Want to run the numbers on your part? Serial production with FDM 3D printing