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.
RE: Failed Y-calibration of a new CoreOne
I am having the Y-Axis failure myself. I upgraded to the Core One + from the Mk4S after getting a serious blob. I was able to get the X and Y axis test to complete once but then the Homing Calibration would not complete. I tried tightening the belts (by the way this looks like a great application for AI), my chassis is square as i loosened the tension screw and followed that procedure and still no go. I did notice something last night when I was just moving the Y axis. When I move the Y axis the X axis will not remain static. What I meant is if i move the print head all way to the front right corner when I drive the Y axis back or forward the print head moves towards the left side of the printer. I'm thinking that the pulley on the X axis motor may be loose. Am i crazy for taking the motor out or is there something software or configuration wise that cold resolve this? I purchased the kit from Printed Solid and have yet to contact them.
RE: Failed Y-calibration of a new CoreOne
@gooner
What I meant is if i move the print head all way to the front right corner when I drive the Y axis back or forward the print head moves towards the left side of the printer. I'm thinking that the pulley on the X axis motor may be loose.
Yes, it's either the pulley on the motor shaft is loose and the grub screw needs to be tightened against the flat part of the spindle. Also make sure they where installed in the correct orientation. It could also be a problem with belt routing but less likely.
One thing to keep in mind, on a CoreXY system the two motors are more correctly labeled A and B. Take a look at the belts in the back of the printer, then manually move the head in the X direction (left to right) you should see both belts moving together in the same direction. If you then move only in Y (back to front) the two belts should move in the opposite directions. If you move diagonally from front-left to back-right then only the top belt should move (the bottom belt should be stationary) and if you move from back-left to front-right then only bottom belt should move.
RE: Failed Y-calibration of a new CoreOne
I'm sure there are other reasons for this but I had exactly the same experience before discovering that I'd installed one of my motor pulleys upside down, once I reinstalled it in the correct orientation I could manually move the print head independently in X/Y without it pulling. I was very surprised that the printer somehow passed all the calibration tests after I'd made such a significant mistake.
RE: Failed Y-calibration of a new CoreOne
My belts follow your description. I have never seen this test anywhere and looks like a good note to add to the installation instructions unless it's in there somewhere and I missed it. I did notice when I was doing my rebuild that on one of the motors I had to force the pulley on and on the other It went on easy. My guess is that was the y axis pulley. I enjoy assembling the printers but when it comes to setting the belt tightness I would rather have a dental visit. Thanks for your reply!
RE: Failed Y-calibration of a new CoreOne
While doing the disassembly I can seeI made the same error you did. Like you I got it to pass the x and y test but never the homing. However I did notice if you just needed to tighten the grub screw it can be accessed pretty easily if need be by only taking panels off.
RE: Failed Y-calibration of a new CoreOne
You had to "force" the pulley on? That's not normal. Possibly the grub screw was already inserted and tightened before you did it.
I strongly suspect either of the following:
- One or more of the pulleys are spinning freely on the motor shaft
- One or more of the pulleys are installed upside down.
Take a look at the pulley orientation first through the hexagonal holes in the motor mounts.
RE: Failed Y-calibration of a new CoreOne
Hyiger, the pulley on my y axis was incorrect, I could see it when I looked through the access hole. I remove the two side panels and was able to get the motor out far enough to fix the pulley. Took me all of 30 minutes to accomplish. Thanks for your help!
RE:
The pulley issues caused all weird problems for me! I have just finished assembling my printer and oh boy I had so many calibration issues.
Initially, I had issues with X, Y and homing calibration. I was able to pass those tests after calibrating the belts to 89/91 Hz. However, this didn't prevent all the strange printing issues I encountered.
At first, I was able to start printing and the first layer was perfectly centered and printed correctly, but every layer after that was shifted by ~1 cm on both axes. With other attempts, the printing would randomly start at the edge of the plate. Then suddenly, I failed the Y-axis test. Having checked every side of each belt, I noticed that the rear pulley on the Y axis was not spinning. After unscrewing it (which took forever), I noticed that during assembly what must've happened was that the screw had started threading early at the bottom. This meant that I could not feel the tension, so I kept screwing it in, unaware that I was putting tension on the pulley. I had to fix the threading on the plastic with an M3 threaded insert and a custom M3 screw that I had, which has a thin thread at the top and a smooth core. This solved all my problems, although I did have to calibrate the core axes up to 92/95 Hz to pass all the calibration tests and achieve great print quality.
Given the issues I had with that piece, I'm already printing a backup part!
RE: Failed Y-calibration of a new CoreOne
It was a lot easier for me to get the belt set correctly in the nextruder base with the printer assembled instead of during 5. CoreXY assembly | Y belt guiding: belt tensioner step. It was easier at least for me to pull and get the same length when the assembly is mounted in the printer. For this is the only step that I dread when building your own. Looks like there will be no more kits from now on so I won't have to worry about this.