The PCB Manufacturing Files Used for Circuit Board Fabrication

The first thing your contract manufacturer(CM) will do in manufacturing your PCB is send design data to the PCB fabricator. These files will be used for creating the different layers and images of the bare circuit board, as well as drilling the holes and routing around its exterior. The fabricator will first start with the files needed to make the images for the different board layers. Traditionally, these were Gerber formatted files that drove image creation through a photoplotter onto the film used for PCB fabrication. Now, however, a new file format known as IPC-2581 is beginning to replace the older manufacturing file formats, including Gerber.

IPC-2581 is not simply a Gerber file replacement, but rather an entire database with all the manufacturing data needed for fabrication, assembly, and testing. This new file format contains the image information (Gerber), the drill information (NC drill), American Standard Code for Information Interchange (ASCII) netlist data for testing, and much more. The benefit of IPC-2581 is that the PCB designer no longer needs to generate multiple separate files, but can instead simply output the design job as an IPC-2581 formatted file and submit that to the CM.

Along with creating all of the necessary layer images and laminating the board together, the fabricator will also work on drilling the holes in the board. This information would normally come from an Excellon formatted NC drill file, but is now also contained within the main IPC-2581 data file. Another important part of the data that is also in the IPC-2581 file is a netlist. The netlist allows the fabricator to conduct bare board testing to make sure that their fabrication process hasn’t introduced any unintended shorts.

The fabricator will also use the fabrication drawing that you created for additional information. The fab drawing should have complete dimensions, the locations of unique board features such as slots and holes, and layer stackup information. It is also common to include readme files with the information sent to the PCB fabricator for more specific details on the board, and this information can now also be included with the IPC-2581 file.

Once the fabrication of the board is complete, it will be sent back to the CM for assembly.

If you want more information on PCB manufacturing files or how they’re used during fabrication, contact us!