3D Printable Gears
How to pick module, tolerance, and material for gears that print cleanly on an FDM or resin printer.
FDM printers reproduce involute tooth profiles well down to about module 0.5–1 for PLA/PETG on a 0.4 mm nozzle; module 0.3 teeth are thin enough that flank accuracy suffers unless you're printing resin or using a fine nozzle. As a rule of thumb, keep module × 4 above your nozzle diameter for crisp flanks.
Print gears with the flat face down (teeth extruding in the print's XY plane) so layer lines run along the tooth width rather than across the load-bearing flank — that's exactly the orientation the STL downloads on this site are modeled in.
For meshing pairs, print both gears at the same module and pressure angle and add a small amount of backlash (0.05–0.15 mm depending on printer tolerance) if you're designing a custom pair in the generator rather than using the fixed-backlash catalog defaults.
Recommended modules for FDM
- Module 1–2 — safest for 0.4 mm nozzles, strong teeth, good for load-bearing mechanisms.
- Module 0.5 — fine but printable with a well-tuned printer and a 0.2–0.4 mm nozzle.
- Module 0.3 — best reserved for resin printers or display/low-load models.