Whether you're building a proof-of-concept prototype or preparing for production, submitting complete and accurate design files is the first step toward a successful PCB assembly build.
At Screaming Circuits, we're committed to helping engineers accelerate product development with fast, reliable, quick-turn PCB assembly. A complete design package minimizes delays, streamlines quoting and manufacturing, and enables us to deliver your prototypes as quickly and accurately as possible.
This guide outlines the PCB design files and documentation typically required for a successful assembly build.
Preferred for optimal assembly:
Minimum required:
For fabrication orders, Screaming Circuits requires a drill file (typically in Excellon format) in addition to your intelligent design files. The drill file defines:
Accurate drill data is essential for PCB fabrication. Missing or incorrect drill files can delay or prevent fabrication from proceeding.
Note: A drill file is required for fabrication orders but is not required for assembly-only orders.
The BOM serves as the roadmap for component procurement and assembly.
A well-formatted BOM should include:
Using manufacturer part numbers rather than distributor-specific numbers helps improve sourcing flexibility and can reduce lead-time risks. See our Panelization Guidelines
A pick-and-place (centroid) file is only required when Gerber files are provided in lieu of intelligent design data (such as ODB++ or IPC-2581). Intelligent design files already contain component placement information, eliminating the need for a separate centroid file.
When required, the centroid file tells the assembly equipment where each component belongs on the board and typically includes:
Providing accurate centroid data helps ensure efficient and accurate component placement during assembly.
While not always required, assembly drawings are highly recommended.
Assembly drawings help clarify:
These drawings are especially valuable for complex designs and assemblies containing unusual components.
Include any special manufacturing requirements such as:
A Read-Me document can help communicate project-specific instructions that may not be obvious from the design files alone.
Examples include:
The following issues are among the most common reasons projects are delayed during quoting, fabrication, or assembly.
The board outline should be a single, continuous, closed shape that clearly defines the finished dimensions of the PCB.
For fabrication orders, Gerber files alone do not provide complete hole information. A drill file (typically Excellon format) is required to define hole locations, sizes, and plated/non-plated holes.
Missing manufacturer part numbers, quantities, or reference designators can delay component sourcing, quoting, and assembly.
Include only one manufacturer part number per cell. Approved alternate or substitute part numbers should be listed in their own designated columns or cells.
Use a consistent format for reference designators to improve automated processing and reduce manual review.
When Gerber files are provided instead of intelligent design data (such as ODB++ or IPC-2581), a centroid file is required to define component locations, rotations, and board side. Missing or inaccurate centroid data can delay assembly or require additional engineering review.
Assembly drawings help communicate component orientation, polarity, special assembly instructions, and other critical details. While not always required, they are highly recommended for complex or non-standard assemblies.
Special manufacturing requirements—such as controlled impedance, board thickness, copper weight, surface finish, or other fabrication specifications—should be clearly documented. Missing fabrication notes can result in engineering questions or production delays.
A Read-Me file is a convenient way to communicate project-specific instructions, approved alternate components, revision notes, or other information not captured elsewhere in the design package.
Ensure all submitted files (Gerbers or intelligent design data, BOM, centroid file, assembly drawings, and supporting documentation) represent the same design revision. Mismatched revisions can lead to quoting delays, manufacturing errors, or assembly rework.
Before uploading your design package, verify that you've included the files applicable to your order.
✓ Bill of Materials (BOM) with manufacturer part numbers and approved alternates (if applicable)
✓ All files are from the same design revision
✓ Intelligent design data (ODB++ or IPC-2581) or Gerber files for all board layers
✓ Drill file (required when submitting Gerber files)
✓ Continuous board outline
✓ Fabrication notes (if applicable)
✓ Intelligent design data (ODB++ or IPC-2581) or Gerber files
✓ Pick-and-place (centroid) file (required only when submitting Gerber files)
✓ Assembly drawings (recommended)
✓ Read-Me file with any special assembly instructions or approved component substitutions (recommended)
The faster your manufacturing partner can understand your design, the faster your project can move into production.
Submitting complete, well-organized design files helps reduce questions, minimize delays, improve quoting accuracy, and accelerate turnaround times.
At Screaming Circuits, we're committed to making the transition from PCB design to assembly as seamless as possible. Providing a complete assembly package is one of the easiest ways to help ensure your project gets built right the first time.
Upload your PCB design files and request a quote from the Screaming Circuits team today.