filament feed system problem

Hi all,

I found a problem in the filament feeding system. In my robo 3d the hobbed bolt is mounted between three bearings. I found out that on one bearing, the inner ring and outher ring are in contact with the casing. After 4 weeks printing the big gear seems to tigthen the nut of the hobbed bolt, resulting in a lot resistance at the feeding system. Even so much that the stepmotor could not turn anymore, resulting in a failed print.

I have resolved this problem by taking a bit of the case away with a counterbore.
I have attached a picture.



After this I replaced the third bearing for a nut with two rings, just in case..

Regards,
Arnoud

 

Interesting, I noticed the other day that my hobbed bolt was getting looser with use, so I tightened it. Perhaps this will help me with that.