Check a prototype by confirming which drawing revision is current, comparing each applicable characteristic with the drawing, and recording the result against the stated requirement. A quality control plan may add tolerances, testing parameters, and acceptance criteria, but only where it actually specifies them. Unclear, conflicting, or missing information must remain unresolved rather than being treated as a successful check.
Establish the drawing basis
Begin by obtaining the project’s designated drawing record. Record the drawing identifier, revision, and issue status exactly as shown. A file name, date, or verbal description is not a substitute for confirming that the document is the current project issue.
If several drawings or revisions appear in circulation, resolve which one controls before inspecting the prototype. If the current status cannot be confirmed, the comparison basis is uncertain, so any pass or fail decision would be unsupported.
Create a comparison record
A simple inspection sheet or digital record can keep the drawing requirement and prototype result together:
| Field | What to record |
|---|---|
| Drawing basis | The exact drawing identifier and revision used |
| Characteristic | Each dimension, symbol, note, test, or other requirement being checked |
| Acceptance basis | The applicable drawing requirement and any relevant quality control plan entry |
| Inspection method | The measurement, observation, or test method used |
| Result | The measured value, observed condition, or test outcome |
| Unresolved issues | Missing information, conflicts, limitations, or checks not completed |
| Final status | The conclusion reached only after the requirement and result are both documented |
This is a working record rather than a mandatory project form. Its purpose is to show what was checked, how, and against which requirement.
Compare the prototype
Work through the applicable drawing characteristics systematically. Use a measurement or inspection method suitable for the characteristic and its stated requirement, then place the result beside that requirement for comparison.
Visual inspection alone may support a requirement expressed visually, but it does not establish a measurable result where measurement is called for. Likewise, do not invent or infer a tolerance that is not stated in the applicable documents. An unclear symbol, dimension, note, or reference should be referred for resolution.
ASQ notes that a quality control plan may specify product tolerances, testing parameters, and acceptance criteria. Where such a plan applies, include those entries in the comparison basis and perform the specified tests under the stated parameters. The plan’s general role does not establish that a particular project has particular limits; those values must be confirmed from the project documents.
Keep manufacturing and inspection aligned
NIST states that design and manufacturing information must be communicated to inspection activities, including communicating design intent to digital manufacturing and inspection. For a practical prototype check, this means inspection should use the same confirmed design information that governs manufacturing—not an obsolete drawing, an uncontrolled export, or a verbal summary that omits relevant requirements.
If the prototype and inspection records refer to different revisions, reconcile them before recording conformity. Where interpretation is still uncertain, preserve the issue in the record and obtain a project-specific decision.
What the reader must still confirm
Before accepting a prototype comparison, the project team must confirm:
- Which drawing revision and issue status are current.
- Whether pending changes affect the prototype.
- Which characteristics and requirements apply to this check.
- Whether a quality control plan exists and which version governs the work.
- What tolerances, testing parameters, and acceptance criteria are actually stated.
- How ambiguous or conflicting requirements must be resolved.
- Whether any deviation is permitted and who may authorize it.
- Whether every required measurement or test was completed and documented.
The cited general sources explain what quality plans may contain and why design information must reach inspection activities. They do not provide project-specific drawings, tolerances, test conditions, or acceptance limits, so they cannot by themselves establish that a particular prototype conforms.