Creating a PCB layout design is a tall order. It takes time, electronics knowledge and patience to get it all done. But when you already have the PCB layout ready, there are still files you need to have before you can submit the PCB layout design for printed circuit board manufacturing. For turnkey orders, the files needed are BOM (bill of materials), centroid data and the PCB layout in either Gerber or ODB++ format. Aside from these regular files, it would be helpful if there are additional files such as assembly sketches, fabrication procedures and any other instructions or specifications to the PCB layout design.
The only problem is most electronic manufacturers particularly newbies do not know of these files and how to secure them. Fortunately, there are companies like us who are willing to help them on this problem. In this wiki article, we will take a closer look on the following printed circuit board manufacturing files and why they are necessary for production.
Gerber or ODB++ Files
Gerber and ODB++ are different file formats being run through a software or program in the computer. These set of files contain extensive information about the different layers of the PCB. All these info come in handy for the production team. The most commonly used programs to run these files are either KiCad or Eagle. There are other applications who can read these files as well but the two mentioned are the most heavily used by electronic manufacturers. Also the largest companies in this growing industry use these files.
Aside from the Gerber or ODB++ files, you also have to include drill files and a detailed board outline file. The drill file contains info on the exact location where the manufacturer will put drill holes including the size of these drill holes. The detailed board outline file may cover details such as blind and buried visas which the manufacturer also needs. Make sure you include these files along with the Gerber or ODB++ files.
Last but not the least, you should also include mechanical files in the file set. This is not necessarily a separate file but simply a clear distinction of the board outline file wherein the dimensions of the board are verified. Cut-outs and internal routing can also be specified on each layers for this file. Gerber or ODB++ files can be submitted as an archive which includes all of the aforementioned files together. Any of these are acceptable by electronic manufacturers as part of the PCB layout guidelines.
The Centroid file which is also known as the “XY coordinate” or “Pick & Place” file contains info about where each electrical component are placed on the board. It is presented in an x-y coordinate format with different perspectives in terms of rotation, layers and reference designator. The value/package of these electrical components are also presented accordingly.
Bill of Materials
Bill of materials or simply known as BOM is a lengthy list of all the parts, electrical components and materials included to fill up the electrical circuit diagram. DNI (do not install) components may also be included in this list to make it thorough for all of the components included on the list. Environmental and recycling aspects should be considered when the components and materials are chosen.
Special and Additional Requirements
There are times wherein a PCB layout design includes impedance control, unique stack up & thickness, gold fingers and blind/buried vias etc. These notes can be added as “ReadMe” files or additional PDF files for formality. You need to highlight these specifications on the special/additional requirements files so the PCB manufacturer can note this as a part of the production plan.
Assembly drawings may be necessary if there is no enough space for all of the reference designators on the PCB outline file. Assembly drawings are normally presented as PDF files as a step by step guideline on how to assemble the PCB layout design.
There are times when clients have unfinished PCB layouts due to various reasons and the PCB manufacturer is left being responsible for its completion. This situation is where companies like us or the PCB manufacturers themselves step in and create a preliminary quote based on the existing PCB files necessary for production. As a part of the PCB layout guidelines, any other design updates will help us modify the quote accordingly.
All of the PCB files mentioned above are needed by PCB manufacturers before they can jumpstart printed circuit board manufacturing. There are times when a client is not able to recover all of these files most especially with newbies. However, PCB manufacturers can also assist when it comes to missing PCB files. They are knowledgeable enough to identify and secure it for you as soon as you finalize a contract or deal.