This project is my entry for the design challenge "Pimp My Original Prusa" and it is an upgrade tool.
The idea is born a month ago when I was trying to use my little STARTT 3D printer as a pen plotter to draw circuits on a copper board with a marker. Unfortunately, I don't own a Prusa printer, so this could be a good occasion to develop and share a useful tool for this printer and try to win one :)
The first problem was to find a way to mount "something" on the body of the extruder without changing anything. So I studied the 3D model of the printer and downloaded the printable parts to check a possible place.
The solution that I have found is to unscrew the fan of the extruder and use a special slot where to put it into and screw it back on the extruder.
This piece has one side that presents four holes. These are used to plug the piece that holds the tool in two ways.
The first way is to use standard M4 16mm long screws and hexagonal M4 nuts, and the second is to use neodymium magnets rods on both pieces.
1) I used are cylindrical head M4 screws DIN 7985 stainless steel, and hex nuts stainless a2 UNI 5588, as seen in pictures. The nuts are put in the four slots of the main piece (the fan interface) so they will remain still while screwing.
2) I used Neodymium magnets rods in place of the nuts, and in the holes for the screws in the tool holder.
For the main part I used 5mm x 10mm round rod magnets, and for the holder, I used 5mm x 3mm round rod magnets.
This video shows where magnets are inserted: Animation of the magnets assembly on YouTube
The use of the magnets lets you plug and unplug multiple tools without unscrewing them all times. These new neodymium magnets are strong enough to keep firmly the tool on the body of the extruder:
Video demonstration of the strength of neodymium magnets mounted on the Multi-tool
When there is a permanent marker mounted on the tool:
Video demonstration of the Multi-tool with a permanent marker mounted
If you print several copies of the holder you can exchange different markers or any other tools needed of course.
To use this printer as a plotter you can use the software "FlatCAM" that converts Printer Circuits files or SVG vector graphics into gCode that you can use with the printer. You need some setup to set the offset distance (the pen is not in the same position of the extruder) and the height of the tip. There are many videos on YouTube about this subject.
Together with the basic tool there is a special PCB holder that comes really useful to keep the PCB stick to the magnetic bed of the printer. It's possible to insert the same neodymium magnetic rods inside the holes so it will stay still on the bed while the tool draws on the PCB.
I am sure that this will come handy to many people, lets your creativity to tell you more different uses for this tool.