My Geeetech A10M's extruder idler arms are broken, so I designed a new one to replace them. Use PETG or ENG PLA, Carbon or Glass reinforced PLA to be strong enough.
Note: The hole for the motor axis is 6mm, so you should use the metal tube from original idler arm. (I heated up the arm, and when it melted, I pushed out the metal with a bigger phillips screwdriver.
Geeetech Prusa I3 Pro B / Geeetech A10M
Philament.eu Glass reinforced PLA
Use support top distance and support bottom distance, value 0.2 mm (1 layer) to remove the support correctly. Printed on 200 °C, 50 mm/s