Define the prototypeâs evaluation criteria
Custom CNC prototype machining begins with a controlled part definition and a clear question to test. Identify whether the build evaluates fit, assembly access, a feature, or another design requirement. Mark the dimensions and interfaces that will be reviewed.
Record results against the drawing
After evaluation, record the result for each critical feature and distinguish measured findings from subjective feedback. Identify the drawing dimensions, datum, or interface associated with any issue. Keep the prototype part number and revision attached to the observations.
Approve the next revision
Route design changes through the responsible authority and issue controlled files for the next build. Confirm whether changes affect material, geometry, inspection, finishing, or supplier quote assumptions. Do not treat an informal prototype mark-up as a production release.
Set repeat-order acceptance separately
A successful prototype does not automatically define production acceptance. State the quantity, inspection plan, documentation, packaging, and delivery requirements for later orders. Ask suppliers to confirm whether the new scope differs from the prototype quote.
Keep the build history traceable
Maintain a simple record of revisions, evaluation findings, approved changes, and the next release requirements. This helps ensure the follow-up build reflects the validated design rather than an outdated file set.