Low-Volume Injection Moulding: 100–1,000 Parts and Bridge Tooling
Updated: 2026-10-23
Low-volume injection moulding starts with the question of what the batch must prove. A fit-check model, a material test and a saleable pilot batch have different acceptance requirements. The previously published €3,000 tooling and 100-piece production figures are indicative planning starting points. Actual tooling price, minimum quantity, capability and lead time are confirmed in the written quotation.
What can a prototype tool actually prove?
A single-cavity aluminium prototype tool validates the part design: dimensions against the drawing, assembly with mating parts, material performance under load, cosmetics under agreed lighting. What it cannot fully validate is the production process. A multi-cavity hardened production tool fills differently, cools differently and runs faster; cavity-to-cavity variation and long-run capability only exist once that tool exists.
This is why regulated industries distinguish prototype parts from production-representative parts, and why the T1 sampling process repeats on the production tool even when a prototype tool ran perfectly. Treat prototype results as design evidence, not process sign-off.
Which assumptions are used?
All euro figures below are explicit planning assumptions, excluding VAT, rather than measured market averages or supplier offers. The machine rates match the Nordmould part-cost calculator: €32, €45, €58 and €75/hour. Actual quotations depend on the specified grade, geometry, machine, batch, inspection and delivery requirements. The previously published €3,000 tooling and 100-piece production figures are indicative planning starting points. Actual tooling price, minimum quantity, capability and lead time are confirmed in the written quotation.
How does the calculation work?
Assume tooling of €3,000 and recurring production of €1.20/part. Tool allocation alone is €30 at 100 parts, €6 at 500 and €3 at 1,000. Ordering excess stock only to reduce the displayed unit cost ties up cash and may leave obsolete parts. Compare a stable-design bridge tool against printing or machining using actual supplier quotes, and agree the tool-life target and replacement terms.
| Quantity | Tooling / Cost per part | Production / Cost per part | Total |
|---|---|---|---|
| 100 | €30.00 | €1.20 | €3,120 |
| 500 | €6.00 | €1.20 | €3,600 |
| 1,000 | €3.00 | €1.20 | €4,200 |
Which option should you choose?
Printing or CNC machining can keep an unstable design flexible; a bridge tool can make sense when the grade, drawing and demand have stabilised. A pilot tool may be needed for production-representative process validation. Agree which later changes require new inserts, rework or a replacement tool. Reserve money for one revision before buying stock, and approve samples against a written checklist before releasing the whole batch.
What must the parts prove?
A fit-check model, a material test and a saleable pilot batch have different acceptance requirements. Strength depends on the actual process, grade, orientation and geometry. Do not assume all printed parts are weak across layers or all moulded parts are isotropic. HP offers MJF materials intended for functional production; BASF documents direction-dependent shrinkage in fibre-reinforced moulding. Compare the exact datasheets and test loaded features, weld-line regions and assemblies in the intended process. T1 approval verifies agreed features; it does not automatically prove every lifetime or regulatory requirement.
What should your RFQ include?
Send a STEP model and a PDF drawing with critical dimensions and cosmetic faces marked. State material grade or performance requirements, first-batch quantity, realistic annual demand, colour, finish and inspection documents. Agree which later changes require new inserts, rework or a replacement tool.
Tooling · Cost per part · DFM / RFQ
Which references support the method?
The manufacturer references explain cost drivers and process limitations; they are not sources for our illustrative euro assumptions or proof of Nordmould capacity.
Last reviewed: 2026-08