The more information your PCB fabricator receives about your circuit board needs, the more accurate your quote will be.
In addition, fewer questions about your order will need to be asked at time of manufacture, helping to ensure an on-time delivery.
That’s why Gerber files, which contain information on each physical board layer of your PCB design, are so important.
Here’s a basic Gerber file primer:
Printed circuit boards are created using a computer-aided design (CAD) system which then outputs the PCB fabrication data to allow its manufacture.
This data, also known by the brand name Gerber, is an open two-dimensional vector image format that typically contains a file for each layer (copper, soldermask, legend and/or silkscreen) required to manufacture a PCB.
Gerber files are also the standard input used for PCB manufacturing equipment such as photoplotters, legend printers, direct imagers, automatic optical inspection (AOI), and for electrical test.
For the population or the application of components to the PCB, Gerber files also contain assembly data needed to create solder paste files and the central locations of each component to allow for the programming of their actual placement.
Board fabricators receive the Gerber files in one .zip or .rar archive with the usual standard file extensions for each layer of artwork. For example:
EXTENSION | LAYER |
board.GTP | Top Paste |
board.GTL | Top Layer |
board.GTS | Top Soldermask |
board.GTO | Top Overlay |
board.GBL | Bottom Layer |
board.GBS | Bottom Soldermask |
board.GBO | Bottom Overlay |
board.GBP | Bottom Paste |
board.GKO | Outline |
board.GL2 | Inner Layer 2 |
board.GL3 | Inner Layer 3 |
Contained within the ZIP file, the board fabricator might find a PDF or .dwg file that contains the fabrication drawings describing exactly how the board is to be built.
A file that instructs how the board is to be put in an array or how it is to be panelized may be included, as well.
Need more help with Gerber files or other PCB matters? Reach out to me at greg@directpcb.com.
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