I made this planetary actuator using 3D printed gears. The gear box is connected to a NEMA 17 stepper motor. The ratio should theoretically provide a 5:1 gear ratio, increasing torque of NEMA 17 by 5x. 

I did not want to use the gears provided in the SolidWorks toolbox. So I designed the gears myself in SolidWorks using parametric equation to create an involute curve. This took more time to complete the project but gave me better understanding of gears since lots of research went to learning about involute curve and other parameters such as addendum, dedendum,etc.  

There are still some tolerance issues with the 3D printed gears. I have decided not to use retainer rings, lube, etc to keep my cost for the project low. I plan to make changes in the future and test the actual torque increase using a load cell setup.

• Added mounting holes as well as bearing holders.

• Added bigger bearings to the planet gears

• Better color scheme lol.

• Same as V2 but better tolerances with the 3D printed parts.

• Original NEMA 17 holding torque = 45 Ncm

• Planetary actuator holding torque = 196.2 Ncm

• Efficiency = 87.2%

Testing devices and parameters : 

-> Current = 0.966 A

-> Mass = 2 kg

-> Motor driver = A4988 (rated 1A max)

Stepper motor was driven using A4988 motor driver which is rated for a max 1A current. The NEMA 17 itself is rated for 1.5A so I believe the actuator is more capable than portrayed by this test.