What is urethane casting?

In vacuum casting, a master pattern is used to make a silicone mould, into which casting resin is poured and cured. An ABS-like polyurethane resin is not the same material as injection-moulded ABS.

How should I compare manufacturing costs?

Compare the same part revision, accepted quantity and requirements. Include tooling, replacement moulds, finishing, inspection and delivery; no universal break-even quantity applies.

Urethane Casting vs Injection Moulding and 3D Printing

Updated: 2026-10-22

Urethane casting uses a master pattern and silicone mould to reproduce parts in casting resin. It is worth comparing for small batches when appearance and function need testing before committing to production tooling. Injection moulding uses a production mould and selected moulding grade; 3D printing builds the part without that mould. Choose against the actual requirements, not a fixed batch-size rule.

Which route fits the project?

Design still changing: compare 3D printing; specify build orientation, surface and material requirements.
A repeated small batch from a master: assess urethane casting, including silicone-mould replacement and manual finishing.
A stable design and specified moulding grade: assess injection moulding, with tooling, sample approval and repeat orders priced separately.

Can an ABS-like casting resin replace ABS?

Not automatically. Ask for the exact resin datasheet and assess temperature, loading, ageing, colour and critical dimensions. A similar appearance or hardness does not establish equivalent long-term performance or compliance. Approve representative samples for the intended use.

Renishaw's vacuum-casting process brochure describes the master, silicone mould and resin process. It is a process reference, not confirmation of current material availability or Nordmould capabilities.

How do you compare the total cost?

For each route, compare fixed costs + quantity × recurring cost per accepted part. Include master patterns, replacement moulds, revisions, finishing, inspection, packaging and freight on the same basis. A cheaper first batch may cost more over repeat orders. Keep sample approval and production delivery as separate milestones; confirm the schedule in writing.

What should an enquiry include?

Provide a STEP file, drawing revision, first-batch and repeat quantities, required material properties, critical dimensions and finish. State which requirements are flexible. Use the RFQ brief builder, then the quote comparison tool to check scope and exclusions. Send the project for review; the written proposal must confirm the proposed route and availability.

A worked comparison for an uncertain first order

The following figures are invented teaching inputs, not market prices or Nordmould quotations. Assume an unchanged part and equivalent requirements, with each price covering the accepted part and the same finishing/inspection scope. Taxes, freight, design revisions and financing are excluded; add them before making a purchase decision.

Illustrative route	Fixed cost	Cost per accepted part	100 parts	1,000 parts
3D printing	EUR 0	EUR 25	EUR 2,500	EUR 25,000
Casting	EUR 600	EUR 12	EUR 1,800	EUR 12,600
Injection moulding	EUR 4,000	EUR 3	EUR 4,300	EUR 7,000

Each total is fixed cost + accepted quantity × recurring price. The casting example assumes any replacement silicone moulds are already included in the recurring price; if the quotation charges them separately, add the actual replacement schedule instead. Do not assume unlimited mould life. Under these artificial assumptions, moulding passes casting above about 378 parts: (4,000 − 600) ÷ (12 − 3). The calculation is invalid if the routes fail different requirements or costs change with batch size.

If only 100 parts are currently needed, an attractive 1,000-part total does not justify buying 900 unneeded parts. Request prices for the committed batch and realistic repeat scenarios; make design-change and demand risk visible.

What does a prototype actually prove?

A printed enclosure may establish access, assembly sequence and user feedback. A cast copy may establish appearance and repeated fit. Neither automatically validates the final moulding grade, weld lines, shrinkage or durability of the injection-moulded part. Keep a requirement/test matrix: evidence already obtained, what the chosen prototype can test, and what must be repeated on production-representative samples. Formlabs' process explanation describes making a silicone mould from a master; it does not make a casting resin identical to the future thermoplastic.