If you create rings with polymer clay, these sharp edge deep cutters may become your friends. But! If you print them correctly. To achieve 0.5mm sharp edge follow these printing instructions:

This cutter prints perfectly with FDM printers. I printed mine with Ender 3 using PLA+ (Esun or Sunlu for example for high resistance.)

Printer settings on Cura:

Top/bottom thickness: 15mm Infil: 20 Nozzle: 200-210 Bed: 65 Speed: 40 Spiralize outer contour

Available sizes: 7, 7.5, 8, 8.5, 9.

Good luck and let me know when you print them successfully)