If you want to put an image or drawing onto paper, you’ll most likely use a printer. But plotters are sometimes the better choice. A conventional inkjet printer shoots ink onto the paper line by line, and doesn’t take into account the shape of what it’s printing. Plotters, which are most commonly used for technical drawings, actually trace out the lines just like you would do if you were drawing it by hand. In some cases, that can lead to cleaner results. Bart Dring designed an inexpensive, 3D-printed pen plotter, and has just updated the design.
Pen plotters work a lot like CNC machines and 3D printers, as they move in two or three axes and follow G-code toolpaths. But because they’re just moving a pen across paper, they don’t need to be particularly powerful. Like with his original design, this pen plotter is built from 3D-printed parts and moves each axis along linear rails with belts driven by small stepper motors. The primary change is in how the pen is lifted from the paper. In the original design, that was done in a manner similar to how the X and Y axes are moved. In the new design, the pen is pivoted up and away from the paper.
That provides two advantages: cost and performance. The new design uses an inexpensive hobby servo motor instead of a stepper motor, and it doesn’t require linear rails — just bearings. This mechanism also helps the pen plotter make better contact with the paper. The device is powered by an ESP32 board, and runs software that Dring developed himself. It can accept G-code files, so it’s simple to translate something like a vector image into toolpaths for the plotter to follow. That results in cleanly-drawn lines for your images.