Tarmo 4 Drive shaft upgrade

I designed this drive shaft optimization. It is a hexagonal shape with an increased section.

I had issues with TPU shaft. Indeed, the coupling was grinded in early 15 minutes of uses.

I decided to change the print orientation. It works really well.

Changing the printing orientation is a major improvement. The admissible torque is clearly higher even with low quality PLA. It is due to the fact that the part is stressed in the good orientation (no layer adhesion resistance).

Changing the printing orientation imposes a redesign of the shaft. Printing cylinder in length is not really efficient. This is why I designed a hexagonal shape optimized for 3 printing process.

The coupling should be adjusted or tightened together for better transmission and resistance.

Printed on a Prusa Mk4 with Pineapple yellow Prusament PLA.

CAUTION :

You'll probably have to change the battery support in order to avoid interferences with this new bigger shaft. I already have  changed mine cause I used a bigger battery, I forgot to change the clearances…

Printing parameter : 

10 perimeters

No supports

I designed this drive shaft optimization. It is an hexagonal shape with an increased section.

I had issues with TPU shaft. Indeed, the coupling were grinded in early 15 minutes of uses.

I decided to change the print orientation. It work really well.