What should your next prototype prove?

Write the decision in one sentence

“We need a prototype” leaves the next step open to interpretation. A more useful brief names what the team will decide after seeing or testing the result.

This distinction helps the team choose what to build and what evidence to collect. It does not promise that a particular printing process will answer every engineering question.

Separate a part order from development work

If the design is defined, prepare the model, quantity, intended material, finish, critical features, and inspection expectations. A part supplier can then evaluate a concrete request.

If the design is still changing, identify who will develop it and who decides the next revision. State whether the engagement includes modelling, fabrication, assembly, testing, or only some of those tasks.

Our cross-discipline perspective is to make the next handoff explicit: a digital change should relate to a physical question, and the physical result should inform a recorded decision. A delivered object without that connection may leave the original uncertainty unresolved.

Agree what will be checked

List the features that matter to the decision, the conditions under which they will be checked, and the evidence you expect back. A visual check and a dimensional report are different deliverables.

Use the selected supplier’s guidance for the specific process and material. Protolabs publishes process-dependent design guidelines, while Xometry distinguishes additive inspection options. Neither should be reduced to a single universal tolerance number.

• Identify the critical features and their intended function.
• State the test or review conditions and who supplies any mating components.
• Agree whether measurements or other records are required.
• Identify who reviews the result and authorizes the next step.

A stated goal is not the same as demonstrated capability. Confirm feasibility and acceptance conditions with the supplier before committing to a build.

Keep a short decision record

After the review, record what was built, what was observed, and what happens next. Keep that record with the model revision and the agreed test conditions so a later team member can understand why the design changed.

For a prototype that also needs a website, demonstration, or public presentation, use the shared project-brief checklist. It keeps the physical build and its digital presentation tied to the same intended outcome.