Strain Wave Gear (Harmonic Drive) Wave Generator Balls 

Thank you Haensel, happy to help people to learn a bit more in this field :)

Thanks Henrique!

Hi @bschwand I already tried that, the cage has advantage for the assembly but what I found, space between balls gets bigger so the contact pressure between the flexspline and the circular spline decreases. The pressure is not that high and plastic is flexible, so its not as stiff as metal so teeth skip easily when the wave generator is pressing that area with no ball.

@@ZeroBacklashRobotics makes sense. Maybe a thin cage would work, keeping like half a ball diameter space between each ?

Maybe but bear in mind needs to be easy printable otherwise it will be weak.

Yes, more teeth engaged so more torque for the same size before they skip or break.

desired payload and speed control everything else. If you start at the motor you're at the wrong end, like building a car starting with the steering wheel.

Hi @Federico as @Dan mentioned. You should start defining tour payload, but also your reachability. The approach I follow is once these two targets are clear, I start calculating from further joint to the closest near the base. Then with every calculation you know the weight of the motor that your next motor needs to hold. In case of delta robot, if it has 3 arms you can follow this approach for one arm, the others will be identical taking into consideration that the payload will be split between the 3 arms. For the torque calculation always take the worse case scenario. Furthest point with max load.

Hi Dmitriy, I didn’t try PETG but indeed It could be a better option. Its more flexible than PLA and more resistant. If you try please let us know if it works :)

3d printed

Yes, PLA 3D printed :)

Hi Szilágyi, could you finally manage it?

@@ZeroBacklashRobotics Nope. I tried to print the wave generator and the hub together with the balls placed in halfway through but that was also unsuccesful. I'll try a different material, my PLA seems to be way too brittle.

Ok, thanks. Keep us posted!

@@mrraimundo130your print settings may be off. You can adjust horizontal expansion a tiny bit (if you are using a 4mm nozzle) but i'd recommend a smaller nozzle for this print. I will probably change my nozzle to print the flex splines.