Identify what the first build pays for
List engineering review, tooling, fixtures, test preparation and sample-specific handling. The prototype planning guide helps tie those expenses to decisions the build must resolve. A small sample order can have a high apparent unit cost when setup is distributed across few usable parts.
Prototype and repeat-build cost review
| Item | Prototype question | Production question |
|---|---|---|
| Tooling and setup | What is created for the first build? | What can be reused? |
| Construction | Which features must be representative? | What is the frozen release? |
| Testing | What design question is being answered? | What acceptance repeats each lot? |
Make repeat assumptions visible
State whether tools, fixtures and approved material choices can be reused, under what conditions and for which revision. Use the production-transfer checklist to close deviations before asking for a repeat-build price. A forecast quantity should be labeled as a planning scenario unless it is a committed order.
Compare quantity breaks using the same construction and delivered scope. Ask what changes if orders are split over time. Material availability, component procurement and setup frequency may change the commercial proposal; avoid projecting one prototype quotation into an indefinite production cost.
Do not remove learning from the cost comparison
A cheap prototype that cannot answer the critical fit, assembly or motion question can create a second design cycle. Identify representative features and required test evidence before choosing shortcuts. For production, compare accepted assembled units and recurring controls, including inspection and records that remain necessary after development is complete.
Before you release the design
- List first-build and recurring charges separately.
- State prototype and repeat quantities explicitly.
- Document tooling-reuse assumptions and revision limits.
- Keep required evidence in every compared scope.
Watch points
- Dividing a prototype invoice by its quantity can misrepresent recurring fabrication cost and hide useful development work.
Practical questions
Should prototype pricing be used for the product business case?
Use it as one input, then obtain a reviewed production scenario with stated quantities, scope and reusable setup. Keep uncertainty visible.
Does a production quantity remove engineering charges?
Do not assume so. Ask what work is included, what is separate and how changes to the released design affect tooling and review.
Technical references
References support the material or design context. Check the exact grade, part number, document revision and project conditions before release.Updated 27 September 2026 · Technical content policy · Engineering guidance supports project review; the agreed drawing defines the build.