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Answered Y-Axis Shift Advice

Discussion in 'Troubleshooting' started by Synapse49, Aug 9, 2018.

  1. Synapse49

    Synapse49 New Member

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    Hello hive mind!

    I've got a significant Y-shift issue that I can't seem to troubleshoot. After a forum search, as well as general googling, I understand that shift is normally mechanical. I've got a few photos here of what I'm experiencing. Used a sharpie to outline the layers to make the issue more obvious on the photo.

    I've pulled my machine apart 3 times now; the belt isn't loose, the set screw on the stepper is tight, nothing is bumping the limit switch, etc. I've slowed everything way down. I've printed from both Octoprint and direct from Mattercontrol. The G-Code appears fine in layer mode, but the problem isn't specific to a particular file anyhow.

    Could it be that the stepper motor is on it's way out? If not, any other leads to chase? I only started this hobby in early March, when I bought the R1+ new, so I suppose I could go the way of a support ticket as well if that's the recommended course of action.

    Honestly, any and all advice would be appreciated. I have the gcode and all the slicer settings available if that'd be of any use.

    Thanks in advance,

    Synapse

    20180808_210815.jpg
    20180805_115950.jpg
     
  2. Geof

    Geof Volunteer Moderator
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    Hi there,
    By the looks of it the axis that is skipping is the Y axis (bed), is this correct? Just want to be sure. First when it skips (you'll want to watch it print) see if the wiring under the bed is catching on anything, this happens often. If you've already check the belt and pulley and they arnt bad, make sure the bearings the Y belt rides on is ok. I've had those two tighten up on me and wreak havok.

    If all those check out I'd open up the bottom of the machine (mind the wires for the fan that attaches to the bottom cover they are very short) I'd switch the X axis stepper driver with the Y axis stepper driver. If hte problem moves to the X axis you know you have a bad or weak stepper driver and can either tune it or replace it (I vote replace it since they are dirt cheap- really not worth the time IMO).

    Let us know what you find and ask any questions you may have.
     
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  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If the bed is not being shifted from skips/hangs then yes, the stepper motor or the stepper driver would be the next thing to look at.
    In all fairness though, >90% of the time is a mechanical issues like @Geof is saying.
     
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  4. Synapse49

    Synapse49 New Member

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    Geof, thanks for the thoughtful response. Basically "yes" re: the y-axis (bed) direction and "i did that" to all of those things to check... I'm glad I'm on the right track to narrowing this down! :)

    Swapping the motors is one of those brilliant ideas that is so deceptively obvious that I hadn't thought of that. I'll give it a try... And yah, I've already got a motor on it's way. Even if it's not the problem, no harm in spending $13 on a spare part for when I DO need it! :)

    Happy printing!

    Synapse
     
  5. Geof

    Geof Volunteer Moderator
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    I have a whole pile of parts for these machines because they are so cheap. lol. Every few months buy something for a rainy day. if you do in fact swap the drivers and find a failed driver and just want to replace it I like these kits. I have not had a bad one yet plus both ramps/arduino, all the drivers/heatsinks and an LCD controller. Great little kits.
    Not recommending this specific one, just showing you an example (this is the one I bought)
    https://www.amazon.com/kuman-Printe...=8-3-fkmr0&keywords=kaufman+ramps+arduino+kit
     
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  6. Synapse49

    Synapse49 New Member

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    Thanks! I can understand the skepticism about the probable mechanical issue.

    Assuming I'm the rare case here (lol), any advice on the stepper driver check? I'm a noob at this... Any go-to literature/video which could help educate me on troubleshooting/updating a stepper driver?

    Thanks!

    Synapse
     
  7. Synapse49

    Synapse49 New Member

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    Great! I felt stoked about setting up the RaspPi for Octoprint... A kit like like looks both intimidating and fun!! (Good idea about rainy day parts)
     
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Well, the only real way to test it is to swap it out. By 'it' I mean the stepper motor or the stepper driver :)
    The stepper motors are really cheap and so are the stepper drivers (the links go to examples, not promoting a vendor, shop around -- you can find cheaper ones that do not include prime free shipping).

    If you are adventurous you can swap them with another stepper and stepper driver in the machine (say swap the Y for the X) and see if the problem moves to the X axis :)
     
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  9. Synapse49

    Synapse49 New Member

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    So today I learned what a stepper driver is! ;)

    I'm feeling adventurous. Someone should take Amazon Prime away from me. ;)
     
  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    This is an older, but decent diagram (standard RAMPS, connectors are slightly different from R1+):

    maxresdefault.jpg

    They basically turn the signal from the RAMPS into current to step the steppers :)

    It can be difficult to tell if it is the stepper motor or the driver failing which is why you need to swap in replacements. One at a time if you want to really know which is the problem.
     
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