3D Printing or Injection Moulding: Which Pays off When
When 3D printing pays off and when injection moulding does: mould cost, cost per part, lead times, materials, tolerances and break-even for 10 to 5,000 parts.
Short answer: up to a few hundred pieces, 3D printing is almost always cheaper and faster because it needs no mould. From roughly a thousand identical parts, injection moulding starts to win: the mould costs thousands of euros, but every further moulded part costs tens of cents. Between 300 and 2,000 pieces the decision depends on part size, material and whether the design is final or still changing.
This article compares the two on mould cost, cost per part, lead time, design freedom, materials, tolerances and surface finish, with a break-even calculation for 10, 100, 1,000 and 5,000 pieces and a decision table.
How Does the Cost Structure Differ?
Injection moulding has a high fixed cost and a low cost per part. The mould is machined first, usually from aluminium or steel. Then molten granulate is injected in cycles lasting seconds, and each part costs only material, machine time and labour.
3D printing has no fixed cost beyond file preparation, and the first piece costs about the same as the thousandth. The price follows weight and print time: in Slovakia FDM runs at about €0.05 to €0.20 per gram for common materials, SLA at €0.15 to €0.30. The full breakdown is in how much 3D printing costs.
| Item | Injection moulding | 3D printing (FDM, SLA) |
|---|---|---|
| Fixed cost | mould: hundreds to tens of thousands of euros | none, only file preparation |
| Cost per part | tens of cents to a few euros | a few euros to tens of euros |
| First part in hand | weeks | days |
| Design change | mould rework or a new mould | a new file |
How Much Does an Injection Mould Cost?
Public toolmaker prices are rare because every mould is quoted against a specific part. Published ranges as a guide:
| Source | Mould type | Price |
|---|---|---|
| Easyplast (Czechia), public example price list | simple hand-operated mould, parts up to 50 mm | 8,000 to 35,000 CZK, about €320 to €1,400 |
| Easyplast (Czechia) | automatic mould for the same parts | 50,000 to 90,000 CZK, about €2,000 to €3,600 |
| Formlabs, cost guide | machined aluminium mould for 1,000 to 5,000 units | $2,000 to $5,000 |
| Formlabs, cost guide | steel mould for 10,000 units and more | $5,000 to $100,000 |
| Protolabs | aluminium mould for prototypes and small series | from about $1,500 |
The CZK conversion is indicative at roughly 25 CZK per euro. Every extra cavity, side action for undercuts, polished finish and tight tolerance pushes the price up. Aluminium is cheaper and faster and, according to Protolabs, produces at least 10,000 parts; steel is their choice for over a million parts and does not pay off in small series.
What Does One Part Cost When Moulded and When Printed?
With moulding the part price is low. For small technical parts Easyplast lists 0.60 to 2.80 CZK per piece from an automatic mould and 6 to 7 CZK from a hand-operated one, about €0.03 to €0.30. Formlabs’ example counts $0.50 of material and $1 to $2.50 of labour per part, plus machine set-up for every batch.
With 3D printing the price per piece barely moves with quantity. A 40 g PETG electronics enclosure comes to €2 to €8 per piece at market rates; dozens of pieces on one build plate push it towards the lower end, thousands do not push it further.
Where Is the Break-Even Point?
The break-even is the quantity at which the mould plus the moulded parts cost the same as the printed parts: mould cost divided by the difference between the printed and the moulded part price.
Assumptions, taken from the sources above rather than our own prices:
- part: electronics enclosure 80 × 60 × 30 mm, 40 g,
- FDM printing: €0.10 per gram, so €4.00 per piece, no volume discount,
- simple hand-operated mould: €1,000 plus €0.30 per piece,
- automatic aluminium mould: €3,000 plus €1.00 per piece including material, machine time and labour,
- excl. VAT, delivery and machine set-up per batch.
| Quantity | FDM printing (€4.00 each) | Simple mould (€1,000 + €0.30 each) | Aluminium mould (€3,000 + €1.00 each) |
|---|---|---|---|
| 10 | €40 (€4.00 each) | €1,003 (€100.30 each) | €3,010 (€301.00 each) |
| 100 | €400 (€4.00 each) | €1,030 (€10.30 each) | €3,100 (€31.00 each) |
| 1,000 | €4,000 (€4.00 each) | €1,300 (€1.30 each) | €4,000 (€4.00 each) |
| 5,000 | €20,000 (€4.00 each) | €2,500 (€0.50 each) | €8,000 (€1.60 each) |
The break-even against the simple mould is €1,000 divided by (€4.00 minus €0.30), so 270 pieces. Against the aluminium mould it is €3,000 divided by (€4.00 minus €1.00), so 1,000 pieces.
The numbers shift with the part: a heavier part lowers the break-even, a more complex mould raises it. For a small latch with a $3,600 mould and a $0.32 moulded part, Formlabs calculated a break-even of 13,050 pieces, because it printed in-house at tens of cents per part. Have both routes quoted for your part.
How Long Does a Mould Take, and How Long Does 3D Printing Take?
- Mould: Formlabs gives 3 to 4 weeks for an aluminium mould and 4 to 8 weeks for steel. Protolabs delivers prototype aluminium moulds within 15 days, simple ones within 7. Then come the trial shot, corrections and the batch itself.
- 3D printing: FDM parts up to 250 mm are usually ready in 3 to 5 working days, SLA in 3 to 6.
Lead time decides when parts are needed for sampling, a trade fair or customer testing.
How Much Design Freedom Do You Have?
A moulded part has to come out of the mould. Protolabs recommends 0.5 to 2 degrees of draft on vertical walls, uniform walls, ribs at no more than 60% of wall thickness, and side actions for undercuts, which make the mould dearer. Internal cavities and locked geometries are expensive or impossible.
3D printing has none of these limits: internal channels, undercuts, variable wall thickness and lattice infill all print. A design change costs a new file and one print. With a mould it means machining the cavity again, which takes days to weeks even on aluminium.
Which Materials and What Accuracy?
| Criterion | Injection moulding | 3D printing |
|---|---|---|
| Materials | PP, PE, ABS, PC, POM, PA6 and PA66 with 30% glass, TPE: thousands of granulates with datasheet properties | FDM: PLA, PETG, ASA, nylon, PC, PA-CF, TPU; SLA: resins from standard to heat resistant |
| Tolerances | Protolabs guarantees ±0.08 mm plus a material tolerance | igus gives ±0.2% with a minimum of ±0.2 mm for both FDM and SLA |
| Surface | a polished SPI A-1 mould reaches Ra 0.012 to 0.025 µm; textures to VDI 3400 | FDM Ra typically 10 to 25 µm with visible layers; SLA smooth, matt up close |
| Strength | equal in all directions, stable across the series | FDM weaker between layers, SLA resin more brittle |
| Heat resistance | depends on the chosen granulate, including glass-filled polyamides | PLA 60 °C, ASA 95 °C, PC and nylon higher |
A moulded PA66 GF30 part has no direct printed substitute: printed PA-CF comes close in strength, not under heat and sustained load. For such parts we print the prototype and recommend moulding the series.
What Does the Hybrid Route Look Like?
Most companies asking “3D printing or injection moulding” end up needing both. The sequence that saves the most money:
- A 3D printed prototype. Verify dimensions, assembly and ergonomics on 1 to 5 pieces. Every mistake you find here would cost thousands of euros in a mould.
- A 3D printed pilot series. 20 to 300 pieces for tests, certification and first customers. The design may still change.
- Design freeze and the mould. Order the mould only once the part no longer changes and the volume is certain: aluminium for thousands of parts, steel for hundreds of thousands.
- Printed mould inserts as a bridge. Formlabs documents SLA inserts in Rigid 10K resin set in a metal frame: hundreds to thousands of shots with PP, PE and TPE, fewer with PA and PC. IPC injected 1,000 PP parts from one insert; Braskem ran 1,500 to 2,500 cycles. An insert takes 3 to 5 days instead of 3 to 4 weeks for aluminium.
OutsideDbox covers the first two steps: FDM and SLA printing of prototypes and small series for companies. We do not make moulds. If your series belongs in moulding, we say so in the quote and prepare the prototype mould-ready: draft angles, uniform walls, a parting line.
When to Choose 3D Printing and When to Choose Moulding?
| Choose 3D printing when | Choose injection moulding when |
|---|---|
| you need 1 to a few hundred pieces | you need thousands of pieces and the volume is certain |
| you need the parts within days | several weeks for a mould is acceptable |
| the design will still change | the design is frozen and tested |
| the part has internal channels, undercuts or lattices | the part can be moulded with draft and without undercuts |
| every piece is different or personalised | every piece is identical |
| ±0.2 mm and a layered surface are enough | you need ±0.08 mm, a glossy surface or a specific granulate |
| you do not want thousands of euros tied up in a tool | the cost per part has to fall below €1 |
Frequently Asked Questions
From how many pieces does injection moulding pay off?
From a few hundred pieces with a simple mould, from about 1,000 with an aluminium mould costing thousands of euros. The exact figure is the mould cost divided by the difference between the printed and the moulded part price.
How much does an injection mould cost?
Published examples: 8,000 to 90,000 CZK for simple moulds for parts up to 50 mm at a Czech moulder; $2,000 to $5,000 for aluminium and $5,000 to $100,000 for steel according to Formlabs. Complexity, cavity count and finish multiply the price.
How many pieces can 3D printing make economically?
Single pieces to hundreds without a second thought. At 1,000 pieces of a small part FDM still matches an aluminium mould; above that printing loses, unless the pieces differ.
Can a 3D printed prototype be used to verify a part before the mould?
Yes, that is exactly what it is for. You verify dimensions, assembly and function before the mould is machined. We print in the material closest to the target granulate and add draft angles and uniform walls.
Is a printed part as strong as a moulded one?
Not entirely. An FDM part is weaker between layers and SLA resin is more brittle than moulded PP or PA. For functional tests that is usually enough; for sustained load at higher temperatures we recommend moulding.
What if I need 500 pieces in a granulate that cannot be printed?
Consider a printed mould insert or a simple aluminium mould. Both routes give parts in the target material for a fraction of the price of a steel mould.
How Do You Start?
- Upload your STL to the 3D printing calculator to see weight and print time straight away.
- Send a quote request with the part, the quantity and whether the design will still change.
- Within 48 hours you get a price and lead time for printing. If the series belongs in moulding, we tell you.
Sources
- Easyplast, Ceny plastových výlisků: easyplast.cz
- Formlabs, How to Estimate Injection Molding Cost: formlabs.com
- Formlabs, Race to 1,000 Parts: formlabs.com
- Formlabs, Low-Volume Rapid Injection Molding With 3D Printed Molds: formlabs.com
- Protolabs, Prototyping Services with Injection Moulding: protolabs.com
- Protolabs, When Aluminum Outshines Steel: protolabs.com
- Protolabs, Design Guidelines for Injection Molding: protolabs.com
- Protolabs, Conquering Undercut Design Issues: protolabs.com
- igus, Dimensional deviations in 3D printing processes: blog.igus.eu
- Xometry, Injection Molded Surface Finishes (SPI): xometry.com
- Makerverse, Surface Roughness in 3D Printing: makerverse.com
- ISO 20457:2018, Plastics moulded parts, Tolerances: iso.org