Gantry won’t stay aligned/flush with front
So my Core One had issues right away out of the box with belt tension which I was able to adjust and get working after hours of messing with the tuner. I’ve been able to print for about a week, nothing crazy. The gantry went flush with the front bracket and got the belts close to 85hz. However now I’ve run into issues again and now the gantry won’t sit flush with the front bracket no matter how loose I make the belts after following the guide. It immediately retracts on both sides. Video attached - I’ve tried connecting with support chat a couple times but it keeps timing out before I can connect. Anyone have any ideas of what I can do? This is my first 3D printer and fixing the thing has been my hobby more than actual printing. IMG_3801
RE: Gantry won’t stay aligned/flush with front
That article is rubbish. I think the issue is that it starts from an assumption of some tension on the belts. You could try pushing the gantry to the back and tuning the belts to 85hz then pull the extruder to the front and check for alignment on the gantry. If it doesn't touch both side loosen the bolt a bit on the side that it touching and then push the gantry back and bring in to touch and see if both sides touch. repeat until the gantry touches both sides. You then can push the assembly to the back and tune it.
The thing when tuning it is that you are aiming for about 85 hz, however when you tighten the bolts you need to turn them both by the same amount. this will likely result in both belts having slightly different tunings, but it will work fine (Prusa say they'll be within 3Hz, but mine was 6Hz difference and ran fine).
Once you've got it up and running run the Y callibration again from the menu.
FWIW there is another (large) thread here about more physical adjustment on the gantry, but I'm not sure on the use of it.
I'm also massively doubtful of the importance of both sides touching at the same time versus just tuning the belts to 85Hz. In my case if I followed the prusa guidelines I ended up with a small amount of skew but if I just tuned the belts to 85Hz I got almost none. I tried the physical adjustment and that reintroduced the skew.
RE: Gantry won’t stay aligned/flush with front
I found it a bit confusing too - I levelled the gantry but it fell out of alignment again when setting belt tension.
In the end I adjusted enough to align the gantry and just left the belt tension. Maybe I got lucky - have been through a couple of prints now and so far so good - other then the extruder banging itself to death now and then in the front right corner when calibrating, which seems to be a common issue.....
RE: Gantry won’t stay aligned/flush with front
There is a nugget of wisdom in the comments of the alignment guide from prusa which is that the belt tension is slightly less important than the gantry being square so your method is correct.
I found it a bit confusing too - I levelled the gantry but it fell out of alignment again when setting belt tension.
In the end I adjusted enough to align the gantry and just left the belt tension. Maybe I got lucky - have been through a couple of prints now and so far so good - other then the extruder banging itself to death now and then in the front right corner when calibrating, which seems to be a common issue.....
RE: Gantry won’t stay aligned/flush with front
I got it working again last night. Basically what I did was pull the gantry up to the front and tightened the screws on both sides until the gantry was flush on both sides regardless of tuning. THEN I push it back and tuned it as close to 85hz as possible on both sides - but one side was slightly off again when I pulled the gantry back to the front. Then I actually tightened the side that was not hitting the front ever so slightly (not loosened the opposite side) and then it was flush again and the printer calibrated. I think that’s going to be my North Star on tuning the printer from now on since it does sound like being flush against the front is most important.
RE: Gantry won’t stay aligned/flush with front
I got it working again last night. Basically what I did was pull the gantry up to the front and tightened the screws on both sides until the gantry was flush on both sides regardless of tuning. THEN I push it back and tuned it as close to 85hz as possible on both sides - but one side was slightly off again when I pulled the gantry back to the front. Then I actually tightened the side that was not hitting the front ever so slightly (not loosened the opposite side) and then it was flush again and the printer calibrated. I think that’s going to be my North Star on tuning the printer from now on since it does sound like being flush against the front is most important.
The crazy thing is, thst what you did is basically what the guide is trying (and failing) to tell people to do.
Glad you got it working again.
RE: Gantry won’t stay aligned/flush with front
Imho you need to align the setup the gantry without belt tensioning.
Then tension.
Make the printer work something. Then check how it changed, tension and alignment.