Most PCBA delays start with an incomplete file package: a BOM without part numbers, a centroid file that does not match the board, or no polarity information. Use this checklist before you request a quote.
1. Bare board fabrication files
- Gerber files (RS-274X or Gerber X2) for every copper layer, solder mask, silkscreen and paste layer, plus the board outline
- NC drill files (Excellon) for plated and non-plated holes
- Fabrication drawing or notes: layer count and stack-up, board thickness, copper weight, material (e.g. FR-4 with required Tg), surface finish (ENIG, HASL, OSP…), solder mask and silkscreen colors, impedance control if needed
- Alternatively, ODB++ or IPC-2581, which bundle all of the above
2. Bill of Materials (BOM)
The BOM is the most important document for cost and lead time. One line per unique part, with:
- Reference designators (R1, C5, U3…) and quantity per board
- Manufacturer and manufacturer part number (MPN) — not only a description
- Package / footprint
- Approved alternates, or a clear “no substitutions” note for critical parts
- Parts marked DNP (do not populate) and parts you will consign yourself
3. Pick-and-place (centroid / CPL) file
Reference designator, X and Y position, rotation and board side (top/bottom) for every SMT part. Most EDA tools export it directly; make sure units and origin are stated and that it matches the current board revision.
4. Assembly drawing
- Top and bottom views with reference designators
- Polarity and pin-1 marks for diodes, electrolytic capacitors, ICs and connectors
- Special instructions: conformal coating areas, glue, heat-sink assembly, press-fit connectors, labels
5. Programming and test
- Firmware image and programming method (interface, tool, settings)
- Functional test procedure with pass/fail criteria
- Test fixture requirements or test points
- Serial number or label rules
6. Commercial information
- Quantities: prototypes, pilot run, expected annual volume
- Required workmanship class (IPC-A-610 Class 2 is common for commercial products; Class 3 for high-reliability)
- Compliance needs: RoHS, REACH, conformal coating, traceability
- Target delivery date
Package the files in one ZIP with the board revision in the file name. More on PCB assembly, or see the general RFQ preparation guide.