Skrevet af
Peter HansenPeter Hansen er medstifter og 3D-print-ekspert hos 3D Industri Print. Han har over 10 års erfaring med industriel 3D-printproduktion, herunder FDM, SLS og DMLS-teknologier. Peter rådgiver virksomheder om materialevalg, tolerancer og optimering af produktionsflow med additivt fremstilling.
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The fundamental trade-off
The choice between 3D printing and injection molding comes down to one core trade-off: upfront tooling cost vs. per-unit cost. Injection molding requires an expensive mold (€7,000–€70,000+) but delivers very low per-unit costs at high volumes. 3D printing has zero tooling cost but higher per-unit costs — costs that don’t drop with volume the way injection molding does.
Understanding where the break-even point lies for your specific part determines which process wins.
Side-by-side comparison
| Factor | 3D Printing (SLS/MJF) | Injection Molding |
|---|---|---|
| Tooling cost | €0 | €7,000–€70,000+ |
| Lead time to first part | 3–7 days | 6–14 weeks (tooling) |
| Per-unit cost (100 pcs) | Medium | Very high (tooling dominates) |
| Per-unit cost (10,000 pcs) | Medium-high | Low |
| Design changes | Free — just update the file | Expensive — new or modified mold |
| Geometric complexity | No constraints | Draft angles, no undercuts |
| Variants / SKUs | Each variant = one STL file | Each variant = one mold |
| Minimum viable quantity | 1 piece | Hundreds to thousands for ROI |
| Surface finish | Good (SLS: matte, bead-blasted) | Excellent (class A surfaces) |
| Material options | PA12, PA11, TPU, ABS, PEEK | Virtually any thermoplastic |
When 3D printing wins
Low to medium volumes (under 5,000 units)
Tooling for injection molding amortizes over typically 10,000+ units. Below this point, total cost of ownership for 3D printing is usually lower — even though the per-unit price is higher — because you avoid the upfront mold investment entirely.
Complex internal geometry
Injection molding requires the mold to open cleanly and plastic to flow to all points. 3D printing has none of these constraints — internal channels, undercuts, and lattice structures are printed at no extra cost.
Multiple variants
If you produce 20 variants of a product, injection molding requires 20 molds. 3D printing requires 20 STL files and can produce them all in a single machine run.
Fast time-to-market
Injection molding takes 6–14 weeks from design to first production part. 3D printing delivers functional parts in 3–7 days. For time-critical product launches, this difference can determine market success.
Spare parts and on-demand production
3D printing enables true print-on-demand: no inventory, no minimum order quantity, no obsolescence risk. This is transformative for spare parts management and for products with unpredictable demand.
When injection molding wins
- High volumes (10,000+ units/year) — economies of scale dominate at high volumes
- Class A surface finish — glossy, optically smooth surfaces are difficult to achieve with 3D printing without post-processing
- Very low-cost commodity parts — simple geometries in large volumes are cheapest via injection molding
- Materials not printable — certain elastomers and transparent plastics are still better suited to injection molding
- Color in material — injection molding allows precise color matching throughout the part; 3D printed parts are typically painted or dyed
Hybrid approach: the best of both
An increasingly common strategy is hybrid production: 3D print the complex core geometry and assemble with injection-molded standard parts. This reduces the number of expensive molds while preserving design freedom where it matters most.
It’s also common to use 3D printing for pre-production and early sales, then transition to injection molding once volumes justify the tooling investment — and the design has been validated through real customer use.
Calculating your break-even
The break-even calculation is straightforward:
Break-even quantity = Mold cost ÷ (Per-unit injection price − Per-unit 3D print price)
Example: Mold costs €15,000. Injection molding unit cost: €0.80. 3D print unit cost: €4.50. Break-even = €15,000 ÷ (€4.50 − €0.80) = 4,054 units. Below this quantity, 3D printing is cheaper overall.
Get a production analysis for your part
Send us your part file and expected annual volumes. We’ll provide a comparison of 3D printing vs. injection molding costs and recommend the right approach for your production situation.
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