Making a product prototype with a Chinese factory
Choose the prototype method around the question you need to answer: appearance, fit, function or manufacturing feasibility. Record material and process differences, test against written acceptance criteria, and resolve failures before authorising production tooling. Cambridge China Bridge can coordinate this with its staff in China.
Give the prototype a specific job
Ask the factory what this sample is intended to prove. An appearance model can help assess shape and handling; a functional prototype can help assess operation and assembly. Neither automatically proves that the proposed production process will deliver the same result. Write down the unresolved questions before choosing the method.
Send revision-controlled drawings, mating-part details, intended use and acceptance criteria. Separate cosmetic expectations from performance checks, and identify features that must not change. Use our product specification guide for the underlying brief; the prototype request should explain which parts of that brief the sample will validate.
Match the method and material to the question
Ask the factory to name the actual process and material grade, rather than quote simply for a “prototype”. Request an explanation of substitutions and finishing. A painted sample may show the desired appearance while concealing the original surface or a repair.
Use the comparison below to choose a starting route, then ask which production uncertainties it leaves open. If the finished part will be moulded, discuss manufacturing feasibility while the design can still change; our injection-moulded enclosure guide covers that production route.
| Method and material | Useful evidence | What remains unproven |
|---|---|---|
| Additive printing in resin or thermoplastic | Shape, access, handling and assembly layout | Production-material performance and mouldability; build direction and finishing can affect results |
| Machining plastic stock or metal | Fit, interfaces and functional trials in a specified stock material | Behaviour caused by moulding or casting; matching the material name does not match the process |
| Vacuum casting polyurethane in a silicone mould | Appearance, handling and assembly trials using replicated parts | Equivalence to the intended production polymer; request the casting material's own data |
| Cutting and bending sheet metal | Assembly, access, bend layout and fastening trials | Results from different production forming tools, welds or coatings |
| Sewn sample in the intended fabric and trims | Fit, seam placement, closure operation and handling | Repeatability across production materials and operators |
| Prototype injection moulding in the intended resin | Moulded-part fit and functional trials | Repeatability from the final production tool and process; prototype tooling is still an investment |
Record every difference from production
Keep a sample record naming the drawing revision, material grade, supplier, process, finish and assembly method. Ask whether the factory used glue instead of fasteners, machined a moulded feature, hand-trimmed an edge or repaired a defect. Attach photographs and list these departures beside the test results.
Avoid accepting “equivalent material” without an explanation tied to the intended use. Ask for relevant material data and identify checks for heat, load, cleaning, moisture or repeated operation where applicable. Agree what must be repeated using production material and processes. Keep tooling ownership and file access in a separate written agreement, supported by our IP and tooling guide.
Test before authorising production tooling
Agree a test plan before the sample is made. For each check, record the setup, acceptance criterion, result and any failure. Assemble the prototype with actual mating parts where possible, try intended user actions, and inspect it after testing. A successful demonstration filmed by the factory is useful, but request the underlying conditions and inspect a physical sample yourself.
UK guidance requires you to demonstrate that products you make or import meet relevant regulations and safety requirements before placing them on the market. Plan product-specific compliance work alongside engineering trials. Ask the laboratory which materials, finishes and manufacturing processes its proposed tests will represent, and which later changes would need review.
Make tooling approval a documented decision
Before authorising production tooling, review the test results, remaining risks and the factory's production-feasibility feedback. For moulded parts, ask about draft, wall thickness, undercuts, gate locations and ejection. Record which issues are closed, which need tool trials and who accepts each unresolved risk. Do not approve on appearance alone.
Release the agreed drawing revision and material specification in writing. Define the approval checks for parts from the production tool, and require written agreement before substitutions or design changes. Retain the prototype as a reference with its limitations attached; use our sample-to-production guide for controlling the subsequent production handover.
Frequently asked questions
Can a Chinese factory make a prototype from a sketch?
A sketch can start the discussion. Before manufacture, agree dimensions, materials, interfaces and the questions the prototype must answer. Ask who will prepare and approve the drawings.
Which prototype method should I choose?
Choose around the test: a printed model for shape, machined parts for specified stock materials, or moulded samples for moulding-related questions. Ask what each route leaves unproven.
Does a working prototype mean I can order tooling?
Review the test record and production-feasibility feedback first. Resolve design failures and record remaining risks. Plan separate approval of parts made with the production tool.
Can I use a different material for the prototype?
Yes, if the substitution suits the question being tested and is recorded. It may be useful for appearance or fit, but repeat material-sensitive checks with the intended production material and process.