RE: Failed Y-calibration of a new CoreOne
I found this post after failing the initial Y-Axis calibration. I re-did the belt tension. I gave some "persuasion" to the bar that the extruder sits on (as the instructions are now saying). I looked at gaps and did everything I could think of. Then... out of chance... I happened to notice that the filament sensor cable was protruding away from the right wall a bit. I pulled the slack on that to the rear (straightening the cable). No more failed calibration.
RE: Failed Y-calibration of a new CoreOne
I found this post after failing the initial Y-Axis calibration. I re-did the belt tension. I gave some "persuasion" to the bar that the extruder sits on (as the instructions are now saying). I looked at gaps and did everything I could think of. Then... out of chance... I happened to notice that the filament sensor cable was protruding away from the right wall a bit. I pulled the slack on that to the rear (straightening the cable). No more failed calibration.
Yes, besides a bent gantry probably the second most common is the filament sensor cable interfering with the y-axis movement.
RE: Failed Y-calibration of a new CoreOne
I happened to notice that the filament sensor cable was protruding away from the right wall a bit. I pulled the slack on that to the rear (straightening the cable). No more failed calibration.
Yes, that's a classic trap which has been mentioned here quite often. I like to think that I was the first to fall for it. 😉
RE: Failed Y-calibration of a new CoreOne
Yeah - good observation. I did the kit build of my Core One and had the same issue early on - Y axis gantry interference with the filament sensor cable.
RE: Failed Y-calibration of a new CoreOne
I've read through this thread and, quite frankly, I think it's a waste of time trying to correct a new factory-built machine that appears to have a chassis that, in plan, is a parallelogram rather than a rectangle. Increasing belt tension and other fixes is only trying to force the incorrect geometry of the machine's frame into submission, which should be impossible due to other constraints such as the rail bearings etc. being mounted at right angles. Send it back and let Prusa fix it for you.
RE: Failed Y-calibration of a new CoreOne
I've read through this thread and, quite frankly, I think it's a waste of time trying to correct a new factory-built machine that appears to have a chassis that, in plan, is a parallelogram rather than a rectangle. Increasing belt tension and other fixes is only trying to force the incorrect geometry of the machine's frame into submission, which should be impossible due to other constraints such as the rail bearings etc. being mounted at right angles. Send it back and let Prusa fix it for you.
If you have actually read through the entire thread, you will have followed many explorations which are no longer considered the right approach. Prusa have changed their tack on the belt and gantry adjustment a couple of times. The latest belt tensioning procedure no longer expects you to compensate for a skewed gantry by uneven belt tension. To the contrary, it instructs users to tension the belts symmetrically at all times, and provides the stroboscopic tuning assistant which enforces that approach.
Manually squaring the gantry should not be necessary in most factory-assembled Core Ones. If I had the misfortune of receiving a skewed one, or if I end up with a skewed gantry after building the printer from a kit, I would certainly prefer doing the 2-minute adjustment myself over packing up my printer and sending it to Prusa. See "Quick gantry alignment" on the page linked above.
RE: Failed Y-calibration of a new CoreOne
You're right, Jurgen, to a point: I didn't realise that the two pages I read (first and last -- don't know how that happened) were only part of a 22 page thread. But I stand by my stance that a new assembly should be square in all axes before applying any 'fixes', and that the OP should send it back for correction or receive replacement parts to square it up. By installing replacement parts into a factory-built machine the owner loses whatever warranty protection they might have had.
RE: Failed Y-calibration of a new CoreOne
Well, the original post dates back to the very early days of the Core One. Units had just been shipping for a couple of weeks then. Users were in early adopter/pioneer mode, and Prusa was certainly still learning what to watch out for in assembly and alignment.
I trust that Prusa have learned how to adjust gantries properly in the meantime -- the cost of providing tech support to unhappy users must be a strong motivator. And it's clear from following the forum that most users no longer feel like pioneers but just want a working printer. (Except for those in the INDX sub-forum of course...😉)
RE: Failed Y-calibration of a new CoreOne
Yes, what makes the Core One different than the bed slingers (the have a MK4.5 and MK4 also) is that the tension of the belts affect each other and aaffwrct the alignment (perpendicularity) of the gantry. For us earlier adopters on Core One - we had to discover this on our own.