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Failing layers due to underextrusion

Discussion in 'Troubleshooting' started by EvilDrReef, Apr 27, 2020.

  1. EvilDrReef

    EvilDrReef New Member

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    I've had this problem sporadically recently. Every once in awhile, particularly towards the end of a longer print, several layers will just stop extruding. The extruder motor is still spinning, but it doesn't seem like it's jammed or anything. It's not clicking, and it's barely stripping the filament when I pull it out.

    Sometimes the printer will kick back in and start extruding again, sometimes it won't. Either way, if I try to extrude right after I abort the print, nothing will come out. But if I run the filament change wizard, even if I use the exact same spool, it'll work just fine as long as I unload it and load it back in.

    Last week my hobbled bolt came off. I thought for sure that was the culprit, but it's back on and tightened, and the printer is still giving me trouble.

    The thumb screw mechanism seems very wiggly. It's definitely not loose in the traditional sense. It wiggles back and forth. It's always done that, so I didn't think much of it. But now I'm starting to wonder if it's not related somehow.

    I've attached some pictures of some failed prints. I'm also including an Imgur link to an animated gif of the wiggly tension screw. If you need any follow up details, feel free to ask, because I'm not really even sure where to begin on this one. I've surely overlooked an important detail, and I'm more than happy to supply it.

    It's worth mentioning again that it's not every print that fails. I've printed several successful prints these last few weeks. I even have two of those gold parts completed. It just hits and misses.

    https://imgur.com/a/Fjla75q - gif of wiggly tension screw

    Red handle failure.jpg Red handle failure closeup.jpg Gold Top Failure 2.jpg
     
  2. tkoco

    tkoco - -.- --- -.-. ---
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    Thank you for all of the information.

    1) Did you properly align the toothed gear ( hobbled bolt - as you refer to it ) to the filament path? Read this Project thread: http://community.robo3d.com/index.php?threads/fixing-the-wandering-toothed-gear.23700/
    While it is written for the C2 printer, it is applicable to the R2 printer.

    2) The wobble of the tension arm is abnormal. You need to look into that problem and see what is causing the looseness. This Show And Tell thread may help: http://community.robo3d.com/index.php?threads/extruder-tensioner-arm.19892/

    Please let us know how the situation goes.
     
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  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I agree that the lever should not wobble like that. The post that the screw goes into behind it may be cracked or broken.
    Some (most) of the extruder parts are plastic so if you can print at all you might be able to reprint the affected part. Do the partial disassembly to see what is going in.
     
  4. EvilDrReef

    EvilDrReef New Member

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    Thanks for the resources! I took the lever apart, and it doesn't appear to be cracked. The back plate doesn't seem to be damaged either. What DOES seem to be the issue is that the hex screw securing the mechanism is just very loose. I tightened it back up, and I'm going to do a longer test print (probably that red tube again) and get back to everyone when it's done. Stand by! :)
     
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  5. tkoco

    tkoco - -.- --- -.-. ---
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    If the screw continues to get loose, you may want to put a drop of thread lock compound on the screw before tightening it.
     
  6. EvilDrReef

    EvilDrReef New Member

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    Hey everyone, thanks so much for your help. Tightening up that hex bolt really did the trick. I'll keep a much closer eye on that tension mechanism from now on. I knew y'all would get to the bottom of this in no time flat. :)
     
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