Titan Aqua 3mm broken bearings

Hi i just ran into trouble with my titan aqua. I had the problem of finding the right retract value because of massiv jamming and stringing, first i thought it's because of wrong settings, tried everything from 0.0 to 5.0mm in 0.1mm steps, no luck, then played with the retract and unretract speed - that only changed the grinding behaviour of the filament but didn't fixed the jamming/stringing issue, then I reduced the hotend temp to the lowest possible value while still be able to push filament through the nozzle - that helped a little but the extrusion performance was not exisiting anymore. After all that I just tried to recap whats going on ...

I have a
3mm 24V Version aqua cooled Titan with Vulcano Hotend and
0.8mm nozzle and used
PLA and PETG as Filament.

Then I remembered myself of a situation where I was not getting enough filament through the nozzle (like 20 mm³/sec) and increased the pressure on the idler wheel (the spring loaded nut, opposite to the hobbed gear) that fixed the performance issue, but shotly after the jamming/stringing issue arised and after a few days of printing another issue appeared, now the titan aqua is making a squeaky noise while extruding. I read about problem with the bearings and ordered new bearings and replaced the old onces, which where indeed broken. But I didn't connect the preassure/load on the hobbed gear with the broken bearings - for now. After replacing the bearings everything was fine again, but just for a few hours, literally just for a 200% benchy (4 hours print) - mid print the jamming/stringing started again and the bearings are broken again.

I think there a two different design problems leading to that problem:
- the one-sided bearing arrangement of the shaft, and
- that you are able to introduce to much load on the idler wheel with the spring loaded screw in the 3mm version that the bearings can break

So now i'm left with two different options:
- using high throughput with high load on the hobbed gear (not risking grinding on filament) and replacing the bearings after every print
- or using low throughput risking filament grinding mid print (print time for me is 2-4 days in 800x400x400mm print area) due to low load on hobbed gear but saving the bearings

do you have any suggestions?

here you can find a video from the play of the hobbed gear
https://www.udrop.com/byb/VID_20200526_164736.mp4

 

I've put some more time in that, and it looks like e3d sells different types of hobb gear - which I guess is directly related to the bad performance of my first titan aqua (directly from e3d webshop) - now I have two more titan aqua around (one from e3d webshop, one from a reseller) and they are more or less different in terms of bearings and hobb gear.

The first one (bought from e3d webshop in 2019) you directly see the small grooves



the second one


and the last one


i don't know which one is better, maybe someone from e3d can clarify that?!

The bearings and the idler are also different


the pin is flat on both sides or round and the surface of the bearing is some how (bad) ?


can someone help me on that?

Tim