keeps crashing during bed mesh levelling
hi all, I'm fairly new to 3d printing and received my mk3s last week.
I assembled it and have been printing almost non stop and have had nearly flawless prints since I have calibrated everything properly the first day.
Yesterday I had a crash auto detect, and since then the printer has stopped working. the printer kept giving me X and Z issues, and during many of the calibrations the extruder would not go to auto home and start halfway through the X axis, or the Z axis would reset to 0 after a reboot (which I didn't notice until a couple times after reboots) and would go all the way to the right and when calibrating the Z axis it would hit the bottom left of my steel bed because the PINDA probe would be past the bed.
I have now managed to get through these issues, after running the XYZ calibrations after moving the X axis all the way to the left myself first while the printer was off, as well and having to go through the whole wizard set up a few times...but as soon as I now get to the first layer cal, the bed and extruder heat up but the LCD shows 215/0 and 60/0 and the printer gets stuck with the message that it is performing first layer cal and then it won't do anything.
I reset it, pre heat the nozzle to PLA first, then try and do the first layer cal, and while it goes into the 9 points of calibration, at point 5 I think the X motor skips and gives me issues again... I also get the same issue if I try and print from SD card and the printer will go into a loop with the Z cal again
RE: keeps crashing during bed mesh levelling
If a kit, your bearings are probably not lubricated and the mounts are too tight: said another way the axes take too much force to move, and probably stick in spots.
Powered off, the bed should easily slide the full distance front to back when lifting the front of the printer a couple inches. The extruder should move right to left and back with no stutters or stops somewhere around 30-45 degrees tilt. These aren't precise measurements: they are an approximate guide. A gauge to how easy the axes move.
You can also look at the LCD menu for "belt tension" ... anything less than 250 means things are too sticky with too much friction. Smooth working printers seem to hover around 270-280. btw: the numbers are meaningless for belt tension, ignore them for that.
RE: keeps crashing during bed mesh levelling
Maybe a short video (inc. sound) could show the problem with more details.
deactivate crash detection; slide bearings should be easy to move on all positions; plane and leveled bed (if possible, check with gauge or/and straightedge)? belt tension too strong?
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: keeps crashing during bed mesh levelling
Thanks, I have been looking everywhere for the belt tension numbers and finally found them...on the LCD it says the X belt is at 153, so I guess its way too tight, but it had been printing with no issues before...I have been looking for the best way to loosen it, but I think I have to disassemble the back carriage and loosen a couple teeth on the belt?
im just about to leave but ill try and take the carriage apart in a couple hours to see if this will help.
video attached for reference, you can see the X axis stuttering..
ps. just re-read my first post, and its a little all over the place and possibly not very clear...I was just super frustrated at the time having fiddled around with all the calibrations multiple times for about 4h without any luck and different issues popping uo, while the printer had been working no issue for the past week
RE: keeps crashing during bed mesh levelling
Hmm.. it look likes the belt is not the problem. At point 39 you can see, that the motorgear on the x-axis motor is blocking and lost position. You could check the little pin srew on the x-axis gear is stuck. If all (belt, gear, axis glides easy) seems ok it could be a problem with the steppermotor or electronics. Try to move x-axis over LCD-menu. Moving in X+ direction seems ok.
If nothing helps, try reflash firmware or contact Prusa support.
wbr, Karl
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: keeps crashing during bed mesh levelling
Ok, thanks. Just double checking, you mean the set screw that holds the gear that moves the belt on the motor is tight and holding properly on the motor?
RE: keeps crashing during bed mesh levelling
just tried flashing the software, and now it's giving me X axis length error instead through the self test...
I did try moving the X axis before on thee LCD screen and no problems there, could the issue be the belt being too tight? I followed the instructions while building the printer and there is very slight resistance on the belt if I try and pinch it together but its not very hard to do so..
RE: keeps crashing during bed mesh levelling
Friction at 153 is insanely high (lower number means more friction). You've got something binding, seizing bearings, something rubbing that shouldn't, what ever it is it is major.
After watching the video, I'm not sure what Karl is talking about. The gear looks fine. However, you can even see the scar on the top X rod where the bearing is locking up.
You need to lubricate the bearings, and the best way to do that is to take things apart and pack them with grease. It's possible you damaged the bearing when installing the rod. Did any of the balls pop out of any of the bearings during assembly?
ps: and again, the belt tension numbers do NOT indicate anything related to belt tension. And anything below 250 is a problem.
RE: keeps crashing during bed mesh levelling
one of the bearings balls popped out of one of the Y bearings, but not from the X, I did try and be very careful when inserting the shaft through them.
Ill take it apart and grease the bearings, hopefully that solves the issue...and while im doing that I may as well loosen the belt by 2-3 teeth then
RE: keeps crashing during bed mesh levelling
**UPDATE**
I removed the bearings, and put a little bit of the lubricant that Prusa sent with the kit, I also loosened the belt by about 2 teeth (could have been 3, but not sure)and the X belt tension is now 282.
Calibrations all passed, and doing a 1.5h print now to test out.
Thanks for all the help Tim and Karl, hopefully I got all the kinks worked out! 😀
RE: keeps crashing during bed mesh levelling
The x-axis motor, when driving X- sounds like running a crash. Somewhere, what i can't see in the video, there is too much friction. Printer static, bearings all ok?
What happens when you move the x-axis over LCD-menu or by hand?
On calibration point 45 there dropped two small peaces of plastic to the bed. On the same X-position in (X-) direction the axis blocks. Could this be from the Extruder (near linearbearings) or was it only a filamentrest on the nozzle?
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: keeps crashing during bed mesh levelling
Three teeth is a huge change. Probably too much unless you were seriously over stretching the belt. If my belts are close to normal, gaining one tooth on my printer and I have to use tools to stretch it more; I can't do it by hand. Belts need to be free of play, and a few pounds of tension (6 to be exact); no more. The range is 2 lbf to 6 lbf.
Measure tension by deflection: Push X to the left, Y to the rear; midway on the lower belt pull up with 7 ounces force (200 g); the X-belt should deflect 15/64" (6 mm); the Y-belt should deflect 12/64" (4.75 mm).
RE: keeps crashing during bed mesh levelling
All said - if it is printing well, don't worry about the belt tension until you have reason to adjust it.
280 is a good number; my printer shows 290-295.
RE: keeps crashing during bed mesh levelling
@ssaade
good job; still much success and error-free printing !😀
wbr, Karl
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: keeps crashing during bed mesh levelling
If you had a ball pop out of a linear bearing - replace that bearing. It now counts as damaged.
If you keep the printer long enough, you will consider bearings to be consumables. Rods only if you damage them.
Watch for score marks on your rods. There should not be any.