Check your Gerber Files

Got a PCB design and need to generate Gerber files for manufacture? Don't worry, it's easy – most PCB layout programs allow yo to export your designs to Gerber format. Check your program's User Manual first.

Don't forget that you'll also need to generate drill files in addition to your Gerbers. HelloProto.com and manufacturers require that these be in Excellon Nc format.

How to get my Gerbers?

Here are some useful links on how to get useful Gerber and Excellon files out of commonly available PCB design packages.

• Eagle: Follow these excellent instructions.
• Altium DXP: Refer to the Altium user manuals for your version.
• ORCAD: Check out the ORCAD Layout User Manual, Chapters 10 & 11.

Options, options...

There are a number of Gerber file formats in use. The most common are RS-274D and RS-274X. RS-274D is a legacy format, that often usually provides two separate files for each layer of your PCB. This format is not supported by HelloProto.com, and most PCB manufacturers no longer like to receive it. So, in short, you should select Gerber RS-274X frmat when exporting your files.

When exporing to RS-274X, you may be given a number of options. In most programs, the defaults are sensible. However, if you're not sure, you should bear the following in mind:

• Number precision: A precision of 2.4 or 3.4 is usually the best choice. This means numbers are exported to four decimal places. 4.2 or 4.3 have less precision, which can result in slight errors in your exported design if your board is complicated
• Units: Use the same units you designed your board in. Usually, ths is inches, the industry standard. However, if you designed your board in metric units, chose to export in mm. This prevents small rounding errors from affecting the output files. We often see boards with a minimum track width of 7.9999 mils due to such errors. Of course, we know you really mean 8.0 mils, but the fabricators can balk at it.
• Incremental or absolute coordinates? It shouldn't matter – both HelloProto.com and manufacturers can support either. However, Gerber files with absolute coordinates are by far more prevalent than ones with incremental coordinates. So given the choice, to prevent headaches, we recommend that you use absolute coordinates too.

Other considerations

• Copper fill: If your PCB design software composes copper fill areas using many closely-spaced tracks, make sure those tracks are at leat 8 mils in width. Some software uses unfeasibly small tracks. Although humans can sense-check and see that it is a large copper fill area, plotting software can choke on it. If the tracks are wider than 8 mils, you're unlikely to face problems.

Zip them up, send them on

Once you have your files, zip them up and upload them.

Having problems uploading? Ensure that the compressed file is less than 500kB – we impose this file size limit to prevent abuse. You don't need to include any report files, image files, or the board design files – we just want your Gerbers and drill files, and these should usually compess to a very small size.

If you're just over 500kB, try compressing using the bzip2 (.tar.bz2) format – it creates very tiny archives, and HelloProto.com supports them.