Who this is for: Businesses and product managers commissioning a first prototype or deciding what to build in the next iteration.
A prototype can mean very different things: a shape to hold, a basic mechanism that demonstrates movement or an assembly close to the intended product. Before requesting a quotation, decide what the sample must help you learn. A clear question makes it easier to avoid manufacturing work and finishes that do not add useful evidence.
A polished presentation model may be unsuitable for a mechanical test. A working demonstrator may use temporary materials and an unrealistic envelope. Both can be useful if their purpose is explicit and the team understands what has not yet been assessed. The label prototype alone does not establish either point.
Distinguish three practical objectives
These categories are not mandatory stages that every project must follow in order. A functional experiment can run while the product’s appearance remains open, or several forms can be compared before investment in a mechanism. The choice depends on the most important uncertainty at that point in the project.
One specimen can answer several questions, but combining objectives needs consideration. Integrating appearance, mechanics and electronics immediately can make a negative result harder to diagnose. Two focused samples may provide clearer evidence than a complete-looking object whose individual variables cannot be controlled. Decide which information is needed before deciding how complete the sample should look.
Scroll horizontally to see every column.
| Type | Main question | Limit to state |
|---|---|---|
| Appearance or volume model | Are shape, proportions and access suitable? | Does not establish strength or performance |
| Proof of principle | Can the chosen principle perform the function? | May use temporary parts and dimensions |
| Functional prototype | Do the functions operate under the test conditions? | Does not establish manufacturing repeatability |
Decide which characteristics must be representative
Representativeness is not only about appearance. Material, finish, mass, clearances, fasteners or interface behaviour may determine whether a test is informative. Identify which characteristics must resemble the intended product and which can be simplified without changing the answer you are seeking. Record those choices with the sample configuration.
Formlabs notes, for example, that some printed parts can differ from final moulded plastics in thermal resistance or long-term stability. The practical implication is to limit the conclusion to what was actually assessed. A satisfactory result with a temporary material does not automatically establish equivalent behaviour under every condition expected during the final product’s service life.
References: Formlabs — Rapid prototyping: uses and limitations
Write a brief that makes quotations comparable
Specify the sample’s purpose, configuration, quantity, planned tests and required documentation. If it will be used in a commercial presentation, describe the expected finish. If it must be dismantled during testing, access and replaceable components may matter more than appearance. Suppliers need those priorities to propose work that fits the intended use.
Ask quotations to distinguish model preparation, manufacture, post-processing, assembly and included checks. A lower figure may exclude a necessary operation rather than offer the same outcome more efficiently. Agree how design changes will be handled and what makes a sample ready for testing. Include responsibility for confirming that the delivered specimen matches the configuration the test team expects.
Use the result to define the next iteration
Connect observations to decisions after the test. Saying that the prototype works is too general: which functions, under what conditions and with what limitations? Recording the configuration and conditions makes it possible to establish whether the next change improves the result or simply changes the circumstances in which it is observed.
The next iteration should address remaining uncertainties rather than repeat the whole process without a reason. It may concern one component, a production material, an interface or a more representative test. Moving to a pilot batch then introduces questions about repeatability, sourcing and assembly that a single prototype cannot settle, even when its functional performance is encouraging.
Five questions before ordering a prototype
- Which decision will we make from the result?
- Which characteristics must match the intended product?
- What simplifications are acceptable and how will they be recorded?
- Who will run the tests, under which conditions and criteria?
- Which files, samples and results should the business receive?
Common questions
Must the first prototype use production materials?
Only when those materials are needed to answer the test question. A volume model can use different materials. A material-performance assessment requires a choice and preparation method consistent with the property being investigated.
Is a functional prototype ready to sell?
No. Functioning under test conditions does not complete production engineering, applicable assessments or product documentation. Those activities must be defined for the intended use and market.
Sources and further reading
Apply this to your project.
Tell us which uncertainty your prototype needs to resolve. We can help define a useful sample and the checks that should guide your next investment.
Discuss your prototype