FINAL NOTE: I have tried to make this work now as a cutter for vinyl for a lot of time now, I give up. There are really low cost but working cutting plotters on Ebay from as low as 180 Euro. I recommend you don't waste your time with this as a cutting plotter.
This us an updated version of the previous Pen Holder from here:
Fusion 360 designs are here:
Pen Sleeve: https://a360.co/2VuHW5P
The design is a bit more streamlined and is intended to be a cutter and pen holder. I have designed this for a Roland Type blade holder as can be found on Ebay or Amazon. The sleeve is made to suit the same 8mm Rotring pen but can obviously be made to suit other pens.
Rotring 8mm Pen with sleeve:
on Z = 4.2
off Z = 10
Cutter (not yet fully tested as I have no means holding down the foil yet):
on Z = 4.5
off Z = 10
IMPORTANT !!! Use "G28 W" on the Prusa i3 MK3 for homing to avoid bed levelling and crashing your pen. The holder can remain mounted with pen/cutter holder removed, its high enough not to cause issues while printing. The on and off values are for the Inkscape plugin to replace the laser on/off commands as described in the video.
I have attempted cutting but I am so far not able to fix the vinyl adhesive foil to the print bed without curling up or getting caught in the blade. I did accidentally also cut in my PEI sheet, be careful !!
More explanation here in this video of Teaching Tech:
For G-Code headers etc have a look at the other Pen Holder linked above. I need to make something to spring load pen and cutter to provide enough down force but not ram pen or cutter into the print bed.
I forgot to mention, the bolt to hold down the cutter holder or pen sleeve is M3 with a washer to catch the rim of sleeve or cutter holder. The mount for the Hotend cooling fan is intentionally rather "slim" to not interfere with airflow, I have not paid much attention mounting it and its only a quick and dirty 0.2 mm 150% speed print with 10% infill, that's why it looks a bit bend I guess. With a bit of care and better print I am convinced it will be OK. It should not need to withstand much force if done right. The cutter blade holder that I have (aluminium part) can not remain in the printed part when used as 3D printer, it will catch on the print bed as its lower than the nozzle.