Do you ever wonder why your PCB maker uses Gerber files? It doesn’t have to do with baby food. Gerber was the company that introduced photoplotting. Early machines used a xenon bulb to project shapes from an aperture to plot on a piece of film. You can then use that film for photolithography which has a lot of uses, including making printed circuit boards. [Wil Straver] decided to make his own photoplotter using a 3D printer in two dimensions and a UV LED. You can see the results in the video below.

A small 3D printed assembly holds a circuit board, the LED, and a magnet to hold it all to the 3D printer. Of course, an LED is a big large for a PCB trace, so he creates a 0.3 mm aperture by printing a mold and using it to cast epoxy to make the part that contacts the PCB film.

The fan control turns the LED on and off, much as laser cutter mods for 3D printers often do. We noticed he uses standard nuts as heat set inserts, and that seems to work well enough, especially since there isn’t much load on them in this application. There were a few iterations of pinholes and mounts, but the final iteration seems to work well. There is even a method to do double-sided boards.

Of course, with a laser cutter and good focusing, you could pull the same trick. Just be aware that some of the “high power” laser modules don’t focus to a dot because of their internal construction. Turns out, there’s more than one way to have a printer help you with PCB production.