The PCB manufacturing process is complex. The precision of the manufactured PCBs hinges on many things, but none more important than complete and accurate design or manufacturing data, most often Gerber files. To produce manufacturing data, a wide variety of PCB design software applications are used, and the complexity of each design can vary significantly. As a result, the manufacturing data generated may not always yield the intended results, leading to board failures, manufacturing delays and increased costs.
This month, in our next few blog posts, we will address the most common problems that we encounter with Gerber files and how to avoid them (we’re going to focus on Gerber files because they’re most common but many of these also apply if you generate ODB++ files). The first three problems are listed below.
Gerber File Problem 1 – Obsolete File Format:
Avoid generating an obsolete file format like Gerber 274D. Gerber 274D is all but extinct today, but be aware that the newer Gerber 274X has also received an update called Gerber X2, and Gerber 274X itself been declared obsolete. This doesn’t mean that Gerber 274X cannot be accepted by your manufacturer (it’s by far the most common format we receive today) but you may want to start looking into the benefits of Gerber X2 – especially if your PCB design software package already supports this format. Interested in more of an education on the Gerber format? Here’s an interview with Ucamco, who owns and maintains the Gerber format.
Gerber File Problem 2 – Confusing File Labels
The naming of each Gerber file should reflect the board layer and be easily interpreted. Each software application may have its own way of exporting the files. That process is fine as long as it either makes obvious sense, or the details of the file names and which layer they correspond to are provided. In most cases these issues can be worked through and figured out, but mistakes can happen when the PCB manufacturer has to interpret & modify data which may results in delays or engineering costs.
Gerber File Problem 3 – Fabrication Drawing
Often there are no “Fabrication Drawings” sent with the Gerber files. A fabrication drawing sometimes provides useful information about the desired board characteristics that are not contained within the Gerber files. In addition to displaying the overall dimensions of the board, they will identify any special cut outs or routing. They can also contain any notes related to the fabrication of the boards such as file names, material type, thickness, finish, etc. Not all PCB design software packages include the ability to generate a fabrication drawing; if yours does not, there’s no need to worry, just create and include a document file which lists any board characteristics not included in your Gerber files.
This is the first post in our three-part series titled Common Problems with Gerber Files and How to Avoid Them. Part 2 will be available on October 17, but in the meantime, if you have any questions please contact our team for assistance.