This is a plotter head module for the WhamBam Mutant system
Prints very well in PLA. I used two 2inch smooth finishing nails as the guide rails for the middle section - (and 2.4mm smooth should work)
print the floating section with 20-30% infill for weight. a m3 hex nut slips in and a m3 screw goes in to secure the pen.

when setting pen offsets find zero of your machine (G1 Z0 F60) and then set the pen depth and move the holder up a mm or so, that lets gravity keep constant pressure on the pen.

there are many ways to create gcode for plotting and your best workflow is the one for you, do some research and find the one that works best. I just suggest a "Z hop" of around 5mm is good because it keeps the pen well above the paper during moves and saves issues.