Good manufacturing notes remove ambiguity without repeating contradictory requirements across several files. Separate the bare-board construction from component assembly and product testing. Use a release manifest to show which files belong together and which document controls when two requirements appear to conflict.
Write a focused fabrication drawing
Include the board identifier and revision, dimensioned outline, thickness and tolerance, layer order, copper requirements, material system, holes, finish and mask requirements. Add controlled impedance, via treatments and edge details where needed. Reference the agreed acceptance requirements and required reports.
Use assembly notes for population and processing
Identify the assembly revision, applicable BOM, fitted variants, polarity and mechanical parts. State programming, firmware, cleaning, coating, adhesive and special handling requirements. Keep process instructions consistent with the actual component limitations and approved manufacturing route.
Resolve dimensions and precedence
Make units explicit and identify whether dimensions describe finished features. Avoid maintaining two unrelated outline definitions without a stated master. If the drawing and machine-readable data disagree, resolve the conflict and issue a coordinated revision before production.
Release a package that can be reconstructed
Include a manifest listing each file, its purpose and revision. Keep approvals and deviations with the package. On a repeat order, the manufacturer should be able to identify the approved configuration without reconstructing it from a long email chain.
Example: replacing an ambiguous note
Instead of saying fill vias as needed, identify the affected via group, its layer span and required filling or capping result. Instead of saying test all boards, define the test method, coverage, limits and required record. Specific instructions make quotations comparable and acceptance reviewable.
Design review checklist
- Separate fabrication, assembly and functional-test requirements.
- State units, finished dimensions and document precedence.
- Reconcile every file to one release revision.
- Include approval responsibility for proposed changes.