Essential File Requirements for PCB Assembly (PCBA)

When preparing for PCB assembly (PCBA), one of the most critical steps is ensuring that you submit the correct and complete set of manufacturing files. Accurate documentation helps contract manufacturers like FanyPCB assemble your printed circuit boards quickly, accurately, and without costly mistakes.

The essential PCB assembly requirements and file types you need to include:

1. Gerber Files

Gerber files are the backbone of the PCB fabrication and assembly process. They contain all the necessary information about your board’s layers—such as copper traces, solder mask, silkscreen, and drill data. These files are crucial for guiding the production of the PCB and ensuring the components align correctly during assembly.

What to include:

• Top and bottom copper layers

• Solder paste and solder mask layers

• Silkscreen layers (top and bottom)

• Drill files (Excellon format)

2. Bill of Materials (BOM)

The BOM file is a comprehensive list of all the components used in your PCB design. It includes details such as part numbers, component values, package types, and reference designators.

BOM file should include:

• Part number or manufacturer part number

• Quantity

• Component description

• Footprint or package

• Reference designators (e.g., R1, C3)

• This file is essential for sourcing the right components, especially if you choose turnkey PCB assembly services where FanyPCB handles procurement.

3. Centroid File (Pick and Place File)

The centroid file—also known as the pick-and-place or XY file—provides the location and orientation of each surface-mount component on the PCB. This is used by automated machines during the SMT (Surface Mount Technology) assembly process.

Details required in the centroid file:

• X and Y coordinates

• Rotation

• Reference designator

• Layer (top or bottom)

4. Assembly Drawing / Instructions

Clear and well-structured PCB assembly instructions guide the technicians or machines during manual and automated placement processes. These drawings include component polarity, orientation notes, and special assembly requirements.

It’s especially useful for mixed assembly types (SMT + through-hole) or double-sided boards.

5. Readme or Special Notes File

If your design includes special instructions—such as component substitutions, assembly priorities, or no-pop (DNP) components—include a dedicated text file or clearly state this information in the BOM or assembly drawings.

At FanyPCB, our experienced team reviews every submitted file to ensure compliance before the assembly begins. We support various assembly services from prototype runs to full turnkey production with RoHS-compliant standards.

Get Started with FanyPCB

Ensure your PCB project runs smoothly by submitting all necessary files from the start. If you're unsure about file formats or naming conventions, our team is here to help.

• Faster turnaround times

• Reduced risk of errors

• Higher assembly accuracy

• Cost-effective production

Learn more about FanyPCB's PCB Assembly Services or upload your design files for a free quote.