I thought this would be worth publishing a log about.

While preforming a load test I found that the flexspline will start to rachet if too much reverse torque is applied. I find this interesting, I was under the impression that the first mode of failure with this version of the flexspline would be the teeth shearing off.

I'll be working on a fix for this issue over the next few days. A few ideas in mind have are:

• Use a less ductile TPU (I have various types on hand)
• Change the tooth profile
• Print the teeth and one boundary layer (in Cura slicer "wall line") in nylon and leave the structure of the flexspline printed in TPU

I've also been given a suggestion by Gabrael Levine, the designer of OpenTorque Actuator, to alter the wave generator geometry to keep a preload on the flexspline. I shall see what works best and include it in the next Open HD revision.