Most quotes that take longer than 24 hours are waiting on missing or ambiguous files, not on pricing. This checklist covers the three archives an efficient PCB order needs: fabrication, assembly and documentation.
1. Start from a frozen revision
Export files from the exact revision you intend to build. Name the archive with the board name and revision, for example controller-revC-fab.zip. If the BOM and the Gerber come from different revisions, the assembly will be wrong even if both files are individually correct.
2. Fabrication archive
- Gerber, RS-274XOne file per layer. Include copper, mask, silkscreen, outline and any mechanical layers used for fabrication.
- NC drillExcellon format, with plated and non-plated holes separated if your CAD tool supports it.
- Stack-up drawingMaterial, Tg, board thickness, copper weight per layer, and impedance targets.
- Fabrication notesSurface finish, mask colour, tolerance class, marking and panel requirements.
3. Assembly archive
| File | Must contain |
|---|---|
| BOM | Reference designator, quantity, manufacturer part number, description, acceptable alternates |
| Centroid | Ref, X, Y, rotation, side; units and origin stated |
| Assembly drawing | Polarity, connectors, no-place parts, hand-solder items and any special instructions |
| Test spec | Test points, nets, firmware version and expected behavior |
4. Check the centroid origin
The single most common assembly error is a centroid file exported with a different origin from the Gerber. If the CAD tool uses board centre for one and lower-left for the other, every part shifts by half the board. Verify by overlaying the centroid on the assembly drawing before you send it.
5. Mark, do not delete, DNP parts
Deleting a no-place part from the BOM but leaving it in the centroid confuses the assembly review. Keep the line in the BOM, mark it DNP, and note it on the assembly drawing. The same applies to parts that are fitted only on certain variants.
6. Write a short read-me
One paragraph saves several emails: quantity, layer count, material, finish, assembly scope, target date and any acceptable substitutes. If you need an NDA, say so before sending files.
A 15-minute file check before sending usually saves a day in quoting and avoids a re-spin. If you are unsure, send the archive and ask us to check it.