Belt tensioning problems
I have been having trouble following the guide for belt tension. I have a semi assembled XL. After failing input shaper calibration, saying X belt was too loose, I checked on the belt tension guide.
https://help.prusa3d.com/article/adjusting-belt-tension-xl_401793
The app to measure the belt tension worked nicely, tried two phones and they showed just about the same results.
After measuring the belts using the app I tried the alignment test and found out that the right side did have some play, but by tightening the right tension screw, the belt obviously gets stiffer on that side. After trying it numerous times I'm now sitting at
Left belt: 84hz
Right belt: 94hz
Alignment on the right side still has about 0.4mm play, if I tighten the right tension screw a little bit it goes away but then the tension for left belt will measures at 102hz.
Am I misunderstanding something, are there any other screws I should be looking at or will repeating the steps of adjusting the tensions screw do anything?
However though, with the 10hz difference and 0.4mm play on the right side, the homing tower prints perfectly.
Should I be worried that the frame is not square etc. and if so how can I make it better? ...or just print happily and don't ask questions?
RE: Belt tensioning problems
I have the exact same problem. If the belts are at 80hz, the right side has play at the front of the y axis and input shaper won't calibrate because it's too loose.
If I tighten the right side almost all the way, it's square but the belts are very different tightnesses.
What did you end up doing?
RE: Belt tensioning problems
Same issue for me, I need to tighten the right one way more to get rid of the gap. Something seems wrong here.
RE: Belt tensioning problems
I figured out my problem. Two problems actually:
1) The left side of the y axis had a piece of plastic stuck between the rail and the outer panel, which was stopping the y axis on the left side from coming all the way to the front. Just a tiny piece of filament from some discarded print but it was making the left side stop prematurely.
2) I pulled that out, then noticed that the y axis wouldn't go all the way to the back either. That was caused by one of the plastic support arms on an extruder. The bottom keyhole on the plastic support was on top of the screw instead of attached. That was causing the y axis to not always go to the back.
My advice is to manually check the y axis front and back, left and right for anything that might be physically blocking it.
RE:
This is still unsolved for me unfortunately, have not contacted Prusa support directly yet. My troubles with this has been there since day one on my semi-assembled XL
RE: Belt tensioning problems
On my XL there was also a gap between the stop and the X-axis on the right-hand side. On the left, it was at the stop.
Right side belt high tension, left side low tension.
No chance of correcting this.
I solved the problem like this!
1.) Loosened the tension on both sides so that the edge of the tensioner is flush with the surface on the back.
2.) Moved the X-axis all the way forwards.
3.) Then I held a sturdy aluminium rod to the upper front and fixed the X-axis on both sides with a cable tie so that the carriage is firmly against both stops and stays there.
4.) Then I tightened the adjusting screws. Half a turn on the right-hand side, then half a turn on the left-hand side.
5.) And so on until I had the feeling that the tension of the belts was sufficient.
6.) Loosened the cable ties, then aligned the X-axis in the centre and measured with the app.
Tension on both sides approximately the same and distance to the front also the same.