Hydra Pro - Front Roller Shims

What is it, and why?

I have been having issues with the front rollers/feeders when running heavier/full rolls of filament in my HydraPro modified Bambu AMS units. This is specifically occurring with the far-left and far-right slots. 

I have been running these two Hydra units (ordered from Voxel) for several months now without issue, but have suddenly been seeing this issue in both units over the last two weeks. I spent a fair but of time checking how everything was installed and making sure everything is aligned and spaced correctly. I made a few minor adjustments, but the rollers continued to pop free on occasion. 

I pulled the AMS units off my shelf so I could get a better view during a print, and what I found is that the outer walls of the hydra around the front shafts were flexing, and this flexing was (in the right combination of circumstances) allowing the roller to pop out enough to jam the feed mechanism. 

Instead of going in and printing a new set of Hydra frames with thicker walls or out of a different material (Voxel prints them in PETG), I decided to make a set of shims that wedge lightly between the AMS shell and the Hydra frame to help mitigate the flex. So far with a weekend or so of printing I have not had the issue reoccur. 

Hopefully this might help someone out there who has a similar issue. 

Features:

These shims are pretty basic. They are just thick enough to put a small amount of pressure on the edges of the Hydra frame to keep it from flexing. There are a set of ‘ears’ that prevent over-insertion of the shim, with an opening between the ears that aligns with either side of the front roller. 

Printing:

These shims are small and are under mild compression once installed. I printed mine out of PLA, and I see no reason they won't hold up with time. No supports needed, run with whatever your standard settings are and you should be fine. 

There are a set of ears on the shim to help with alignment and to stop you from over inserting it.  There is a secondary tab that will aid in removal of the shim if you find you need to reposition it for some reason.