Our kids keep losing the tape dispensers, so I decided to make one. This one fits a standard roll of scotch tape, has printed spring clips that hold the tape securely and printed teeth that cut the tape.
Print it now and be prepared to wrap presents!
P.S. We actually found 2 tape dispensers in the time it took me to perfect the design, but it works great.
2) Insert Tape
The teeth are optimized for 0.2 mm layer height, but other layer heights should work fine. You need to make sure to print hot enough to fuse the layers well, or the spring clips will break off. I had to clean up the spring clips and sand the ledge right before the teeth (so the tape sticks better and doesn't slip when you go to cut it).
I printed with ABS. PLA should work. PLA is more stiff and brittle than ABS, which makes the teeth easier to print and the spring clips harder. PLA spring clips are more likely to break off.
I copied the teeth shape from Jag's tape dispenser. I tried my own shapes first, but none of them cut tape. Finally, I imported Jag's teeth into FreeCAD and modeled native FreeCAD teeth that were the same shape. They worked great. Thanks, Jag! Since, I could not have made the design without Jag's teeth, I have marked this work as a derivative.
One of the tricks to getting a working tape dispener was to make sure the ledge that holds the tape right before the teeth is elevated enough that the tape always hits the ledge before the teeth. Otherwise, you have to hold the tape - and not just the tape dispenser - with one hand while you cut with the other hand.
This was one of the first things that I made in FreeCAD. I have used openscad for my previous designs and I like how openscad allows parameterizing, libraries, and reuse. However, I was impressed with how easy it was to model complex shapes in FreeCAD (non-parametric, of course. FreeCAD supports python scripting, so maybe that could be used to make it parametric). FreeCAD lets you make constrained 2D sketches and then extrude and revolve them and supports boolean operations for CSG modeling as well. FreeCAD also has native support for fillets and chamfers. I am not sure what tool I will use in the future, but it will probably be a mixture of FreeCAD and openscad depending on the project.