Introduction: Before a PCB can go into production, you need a complete set of output files—manufacturing data, assembly files, and documentation. This guide covers everything from Gerber and NC drill files to BOM, Pick-and-Place, STEP models, test reports, and special manufacturing notes, helping you package your files correctly for the factory.
Description: Based on AnyPCBA's small-to-medium volume PCB and PCBA manufacturing experience, this guide explains the complete set of PCB output files—Gerber, NC drill, BOM, Pick-and-Place, STEP, and manufacturing notes—and how DFM review catches issues before production.
Before a circuit board can go into production and assembly, you must generate a set of files to assist your manufacturer.
These are your PCB design output files—also called manufacturing data, fabrication files, or assembly files. The manufacturer and assembler use different sets of files to produce your PCBA. The design team must generate these files before the product is quoted and put into production. Before emailing design files to a manufacturer, always obtain their required list of fabrication and assembly files.
This article covers the complete list of files required for PCB manufacturing and assembly, and how AnyPCBA processes them.
You may not need to generate every file on this list for every manufacturer, but it's best to prepare the complete set so your design can be produced almost anywhere.
These are the "blueprints" used by the factory to manufacture the bare PCB.
Gerber files: The industry-standard format (Gerber RS-274-X/X2, IPC-2581, or ODB++). It contains copper, solder mask, and silkscreen information for each layer.
NC drill files: Used to program CNC drilling machines to place vias and through-holes.
These are the files the factory uses to place components onto the board.
BOM (Bill of Materials): Contains part numbers, specifications, reference designators, and quantities for all components.
Pick-and-Place (Centroid) file: Precisely records the X/Y coordinates and rotation angle of each component on the board.
Fabrication and assembly drawings are like your design blueprint, containing substantial information that machines cannot read.
Usually, you place this information in the quotation file. But providing clear instructions on the drawing ensures the manufacturer accurately understands your special requirements.
STEP files help assembly personnel clearly see the 3D orientation and interference of non-standard components (such as special connectors). This effectively eliminates ambiguity in manufacturing.
This file includes a set of nodes designated for electrical measurement (test points). It can be used for bare board continuity testing or for building PCBA ICT (In-Circuit Test) fixtures.
Some manufacturers may require miscellaneous files, such as:
Schematic and netlist
Mechanical layer Gerber files
Reports with special notes (such as back drilling requirements)
In high-volume manufacturing, some products may require firmware (binary files) flashed onto the PCBA, followed by functional testing. These requirements must be clearly specified, and test fixture design files may be needed.
Before your design enters manufacturing and assembly, the fabrication files must be sent to the factory's DFM (Design for Manufacturing) team for review and quotation.
The manufacturer uses professional CAM software to inspect these files, ensuring the design is within their process capabilities. Checks include clearance, feature size, and feature spacing.
Gerber files are most commonly used for this process. Any qualified manufacturer should be able to inspect standard formats (ODB++ or IPC-2581).
Manufacturing notes are critical: Conformal coating, surface finish, specific materials (such as LPI solder mask), impedance requirements, and stack-up/material specifications should all be clearly specified in the fabrication drawing. Complete, clear manufacturing notes help ensure your design can be produced anywhere.
Your design may also need to be reviewed by assembly personnel to ensure it can be reliably produced without defects.
3.1 Orientation of Polarized Components
In the assembly drawing, some radial or axial lead capacitors and connectors may need to be bent in a very specific direction. Your 3D model and STEP file can clearly show this.
3.2 Press-Fit Connectors
If press-fit connectors are used, they are not covered by standard PCB assembly procedures. You must provide detailed assembly drawings or specific documentation. Without documentation, the factory will typically apply a "standard" treatment that fits most basic designs—which may cause defects.
3.3 Surface Finish and Solder Mask Requirements
If you have special requirements for surface finish (such as ENIG or OSP) or solder mask, you must clearly specify them. Other routine matters can be left to the manufacturer.
At AnyPCBA, we understand that the quality of "design output files" directly determines how smoothly manufacturing and assembly proceed.
Our manufacturing capabilities cover 2 to 64 layers, including HDI, rigid-flex, and high-frequency hybrid. We hold ISO 13485 (medical) and IATF 16949 (automotive) certifications.
When you submit a project to AnyPCBA:
Standardized packaging: We recommend providing a complete zip package containing Gerber, drill files, BOM, Pick-and-Place files (top and bottom), and STEP 3D models.
Free DFM review: Our engineering team checks your files at the quotation stage. If we find trace spacing that is too tight, poorly designed pads, or critical components in the BOM that are out of stock, we tell you before production begins—not after.
Upfront communication on special processes: For heavy copper, impedance control, special surface finishes, and other requirements, our engineers confirm with you during DFM review.
In the past, designers had to manually prepare all output files. Today, most CAD tools (such as Altium Designer) can automatically generate these data packages.
Ready to prepare your files and get a professional DFM review and fast quote? Contact us through the AnyPCBA website.
