CR-6 SE : X,Y positioning problem



  • Hello,

    My CR-6 SE seems to have a X,Y positioning problem. When I start a print, it doesn't start from the middle and sometimes the nozzle tries to go out of the bed... And when I want to auto-level, it doesn't go to the right points and inevitably at one moment it tries to go outside the bed. I first thought that it's a positioning sensor problem and I checked the visible connectors. I also updated the main board and the screen firmwares.
    I managed to print a part with a "manual homing" : I completely pushed the bed in the back and the nozzle on the left. However it doesn't fix the auto-level problem and it's not fully satisfying.

    Thanks in advance for your help,
    Lucien



  • @shinmai Thank you, that is super helpful and makes a lot of sense. I at least know what to look out for now and it sounds like it at least is not something I should have to constantly deal with.



  • @Sonics99 said in CR-6 SE : X,Y positioning problem:

    I presume this helps it determine the ends of x and y so it knows where it is at and can know where the middle is at.

    You got it 100% right. 👍 Stepper motors don't report back positional data (well, the cheap kinds on consumer printers don't, anyway), so the printer relies on keeping track of how it has moved the motors since it last homed to keep track of where everything should be.
    That's why if you do some manual moves right after booting the printer up, without homing first, it'll allow you to bang against the frame of the printer on the side of axes where there aren't limit switches, since it doesn't know to stop in time.

    Well, out of nowhere last night it appeared that when I autohomed it didn't even attempt to go over to the left, it just started from the middle and then went right from there which sent it off the side.

    I've actually had that happen too, once or twice, sometimes the printer will assume that it's position is still accurate, even though it has turned off the motors in between, meaning axes could've been moved by external forces. Very weird for it to happen on homing, though, but sounds like a software bug.
    Good news is that while that's not great for your belts and to a degree your steppers and drivers, it's unlikely to cause any immediately threatening lasting damage. Grinding the belts for extended amounts of time will obviously eventually wear away the timing gearing from the rubber belt, but it'd take a LOT of grinding to cause noticeable damage. Also belts are like a couple of bucks, even if you get the ready measured and terminated Creality branded ones, even less if you order some lengths in bulk and crimp/terminate them yourself.



  • @shinmai

    Haha, fair enough and sorry. My wife shoves me in the tiniest space in the garage for my new hobby, so I couldn't really back up enough to get a full shot.

    With that said, shut it off last night when I was done being frustrated and went to bed. Just went in there to get you a new video and it worked exactly as it should and auto homed fine again and then leveled from the right position.

    So good news, the problem appears to have fixed itself. Bad news, I'm not really sure what the issue was and how to prevent or troubleshoot it in the future.

    Excuse my layman's words, but essentially when it autohomes normally it goes over to the left to click that switch and then the glass bed moves back to click that switch. I presume this helps it determine the ends of x and y so it knows where it is at and can know where the middle is at.

    Well, out of nowhere last night it appeared that when I autohomed it didn't even attempt to go over to the left, it just started from the middle and then went right from there which sent it off the side. It then sent Y back from there which meant that it went back and tried to pass the point that way making the motor make a banging sound as it couldn't actually go further.

    So I think you are right, those limit switches were triggering immediately or weren't getting checked or something. I'm not entirely sure how they work, but that seemed to be throwing it off.



  • I know it's frustrating, but it's kind of hard to really tell much from short clips at random angles, and without sound.
    Unless someone already knows a fix for this issue and can swoop in with an answer, it'd be super helpful if you could shoot a mostly stationary clip, showing the whole printer, with sound, of - say - the homing of the printer, or the ABL if the homing works but ABL fails.

    To give a concrete example, here's a clip of mine homing. You don't need to go all Scorsese on it, as long as it's lit and framed properly and everything is roughly in focus is fine. Just as long as you can hear and see everything relevant, like the sound of the axes moving (my X is making more sound than I'd like, because of how the belt is attached at a weird angle, if anyone has a fix for this HMU), the limit switches clicking, the optical Z endstop triggering, the strain gauge probing the bed, etc.

    From the clips you posted, I didn't really see any erratic moves, it seems to move consistently, just at an offset from where it should, which makes me think of the limit switches. If it does move at inconsistent speeds, or otherwise erratically, I'd go back to my previous suggestion of checking the tensions on the belts and the rollers and making sure that both gantries move smoothly and fairly effortlessly by hand when the stepper motors are off.



  • @Sonics99 said in CR-6 SE : X,Y positioning problem:

    So mine just started doing this.

    Just got done doing 10 or so prints at 6 hours or so each. They all went perfect. I removed the plate and cleaned it all off and prepped it and put it back. I ejected the SD card and took the files off and then put some new files on to continue with some new prints.

    I put the card back in and then went to do an level. The unit immediately started doing the level points, but instead of point 1 being in the front left corner, it was all off and by time I caught it it was like going across the back row at the very far edge of Y, to the point where it was like grinding.

    I tried to stop it by clicking back but that did nothing. It then went off on the X side to where the screen is and tried to go farther than the side of the X axis and made like grinding noises. I powered it off and tried to auto home, that sent it right back off again and tried to go down into the screen again. I manually moved the unit back to the left and tried to auto home again, but now it was way off center and never went all of the way to touch the sensor.

    I've tried with the SD card in and out of the machine in case it was corrupted or something. I guess I need to try reflashing it now, but seems odd to have to do since has been working great besides that.

    Here is a link to some videos of it happening:

    https://imgur.com/a/lcoZGVb



  • So mine just started doing this.

    Just got done doing 10 or so prints at 6 hours or so each. They all went perfect. I removed the plate and cleaned it all off and prepped it and put it back. I ejected the SD card and took the files off and then put some new files on to continue with some new prints.

    I put the card back in and then went to do an level. The unit immediately started doing the level points, but instead of point 1 being in the front left corner, it was all off and by time I caught it it was like going across the back row at the very far edge of Y, to the point where it was like grinding.

    I tried to stop it by clicking back but that did nothing. It then went off on the X side to where the screen is and tried to go farther than the side of the X axis and made like grinding noises. I powered it off and tried to auto home, that sent it right back off again and tried to go down into the screen again. I manually moved the unit back to the left and tried to auto home again, but now it was way off center and never went all of the way to touch the sensor.

    I've tried with the SD card in and out of the machine in case it was corrupted or something. I guess I need to try reflashing it now, but seems odd to have to do since has been working great besides that.



  • Hate to soudn like Creality, but any chance of providing a video?

    Other than that, make sure that everything on the printer is tightened down properly, but not too tight. Does the printer make unusual sounds during travel moves? With the steppers off, do the bed and the hotend move smoothly without much effort?


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