Single Layer Gerber generation in Eagle Light

Pandi August 10, 2016 3 min read

When you’ve finalised your design, the last step before sending it off to the fab house is to generate gerber files. Gerber files are kind of a “universal language” for PCB designs. EAGLE is far from the only PCB CAD software out there, and its design files are nothing like those of Orcad or Altium. Fab houses can’t possibly support every piece of software out there, so we send them the gerber files instead.

Gerber files – note the plurality – each describes the single layers of the PCB. One gerber might describe the silkscreen, while another defines where the top copper is. In all, we’ll generate seven gerber files to send to the fab house.

CAM Processor

Before we get too much further, you’ll need to download another definition file: CAM file.

Then, load up the CAM processor by clicking the CAM icon – – which will open up this window:

To simplify creating Gerber files, Eagle comes with a predefined job for this. It is called gerb274x.cam.

To open it in the CAM Processor click “File->Open->Job…”

Browse to your …/eagle/cam/ folder, and you should see a file called gerb274x.cam. Choose it and click “Open”.

You will now see five tabs in the CAM Processor. Each of these tabs will generate a Gerber file.

*.cmp (Copper, component side)
*.drd (Drill file)
*.dri (Drill Station Info File) – Usually not needed
*.gpi (Photoplotter Info File) – Usually not needed
*.plc (Silk screen, component side)
*.pls (Silk screen, solder side)
*.sol (Copper, solder side)
*.stc (Solder stop mask, component side)
*.sts (Solder stop mask, solder side)

The very first step is the Component side i.e. .CMP file; this file depends upon whether the routing is in bottom layer or Top layer. Suppose if it is a Bottom layer,components side’s followings must be selected

Top
Pads
Vias
Tplace
Tnames

The next step is the Solder side i.e. .SOL datathis is the one where the soldering side will appear in your PCB

Bottom
Pads
Vias
bplace

The next step is the Silkscreen SOL which is “.pls” data.

Silkscreen is normally used on the component side to identify components, test points, PCB and PCBA part numbers, warning symbols, company logos and manufacturer marks.

This is same as .pls file but here the names will be on top side i.e., Silkscreen CMP .plc

Solder mask or solder stop mask or solder resist is a thin lacquer-like layer of polymer that is usually applied to the copper traces of a printed circuit board (PCB) for protection against oxidation and to prevent solder bridges from forming between closely spaced solder pads.