Its for grinding herbs and plant matter.... such as oregano, basil, tyme, mint ETC.

From what I have seen, this is the worlds first 3d printed grinder. The design needs to be refined. currently it works, but not perfectly. I have included the rhino .3dm files and parametric grasshopper definition .ghx if this helps. With support beneath, you could extrude pictures/ text etc and create custom grinders.

slasher is a large grinder with different shaped teeth so the grinder is one-directional and can be seen in the screenshot. grinderting is smaller and similar to classic plastic grinders (photos). Be careful not to be grinding any plastic into your herbs! I printed with ABS but perhaps PLA is better.

I think reasonably slow print speed is best to get good resolution of the teeth, it is however not as good as a grinder created from a mould as it is impossible to get the teeth as sharp with a RepRap.

Peace