Engineering resources
DFM review questions for a specialty PCB
A useful design-for-manufacturing review produces decisions that can be incorporated into a controlled fabrication package. A long list of warnings is less useful if nobody knows which changes are permitted, which require electrical review and which alter the product’s acceptance requirements.
Start with the construction that will actually be ordered
Provide the material designations, stack-up, copper definitions, hole table, finish coverage and mechanical drawing together. Identify unusual requirements explicitly: controlled bond regions, tight connector fits, selective finishes or test evidence that must accompany the lot. A generic capability table cannot resolve how these requirements interact on one specialty board.
Published manufacturing tolerances, such as those documented by Eurocircuits, help show why dimensions need an agreed interpretation. Use your selected supplier’s acknowledged proposal for the order. Do not silently import a third party’s default into a drawing that has a different functional requirement.
Give every finding an actionable record
| Field | Useful content |
|---|---|
| Feature | Layer, coordinates or drawing detail identifying the issue |
| Conflict | Requirement and proposed process condition that disagree |
| Proposed change | Specific geometry, material or document revision |
| Decision owner | Role authorized to approve the affected requirement |
| Closure evidence | Revised file, approval and verification reference |
Example: a hole change is not just a drill-file edit
Hypothetical DFM finding. A fabricator proposes a larger finished hole to simplify a difficult structure. Before approval, determine whether the hole is an electrical via, a component lead hole or a specified connector interface. The same numerical change has different consequences in each case.
For a component hole, check the lead and assembly requirements. For a via, review pad geometry, clearances and any electrical effect. For a connector interface, consult the connector’s governing requirement. Record the resulting decision in the released drawing and data, not only in the DFM conversation. Close the issue only when the package consistently reflects the approved state.
Distinguish recommendations from release conditions
Some findings are optional cost improvements; others prevent fabrication or create an acceptance conflict. Label them accordingly. A quotation can proceed with a documented assumption, but production release should not silently convert an unresolved assumption into an approved requirement.
NASA’s configuration-management guidance emphasizes maintaining consistency between a product and its controlled information. Applied here, that means the approved DFM decision must reach the files used to build and inspect the board. The worksheet above is an editorial application of that principle, not a NASA qualification procedure.
Use the fabrication drawing audit before submitting the package, and identify material-specific questions through the material directory. A closed review should leave one clear production baseline.
Project review
Send your drawing and project requirements for a fabrication review. Identify the board revision, intended material and any acceptance requirements with your attachments.
Sources and scope
References checked 9 October 2026. The worksheets and hypothetical examples are original editorial guidance. They do not establish production settings, material availability or approval of a particular construction.