While 3D printing has been a great thing all by itself, it has also made electromechanical hardware a commodity item. Instead of raiding an old printer for motors and rods of unknown provenance, you can now buy everything very inexpensively due to the economy of scale and offshore manufacturing.
[Mr. Innovation] proves this point with his recent paper cutting machine which feeds and slices paper strips with user-selected width and quantity. He did steal one roller assembly from an old printer, but most of it is straight out of a 3D printer build. There’s NEMA stepper motors, modular motor driver boards, smooth rods, belts, and pulleys.
The blade of the cutter is just a standard snap off box cutter blade. It is angled so it doesn’t drag when the motor pulls it back to the home position after a cut. Honestly, we might have made the paper mechanism retract the paper a bit at that point, but that would be simple to add to the device’s firmware.
You might think an automated paper cutter is a bit lazy, but we could see if you were cutting up flyers for a hackerspace event, or cutting paper insulators to fit in an enclosure for a kit you were selling in small quantities.
The biggest issue we saw was that the machine is open loop. It would have been interesting to put an optical sensor between the roller and the blade. When the paper covered the sensor you’d know the position of the edge and could then move the paper a precise amount, assuming it didn’t slip. Another idea would be to put the sensor after the blade in such a way that it could be moved so that the cut would happen once the paper covered the sensor. You could probably do the same thing with a microswitch or some other sensor.
Still, this looks like a simple but useful project for some leftover 3D printer parts. Just be careful with the open blade.