1. Got a question or need help troubleshooting? Post to the troubleshooting forum or Search the forums!

Kind of jamming issue, and layer shifting

Discussion in 'Troubleshooting' started by SoLongSidekick, Apr 30, 2019.

  1. SoLongSidekick

    SoLongSidekick Active Member

    Joined:
    Mar 6, 2014
    Messages:
    220
    Likes Received:
    68
    Hey all,

    So I've got 2 issues left with my C2, one of them new. The new one is this weird jamming issue I've been having just lately. A print will fail, looking like a jam or filament break. I check and the filament is ok, and when I push down on it into the extruder it feels like it's hit a wall. Then with a little pressure it breaks through and extrudes fine. What the hell could this be? I've already printed a replacement carriage so I can replace the stock hotend with a spare E3Dv6 I have laying around, but I haven't gotten around to it. This may be what I have to do.

    The second issue I've had ever since my first print. Random layer shifting. I'm having to print at 40mm/sec and move at 80mm/sec. I've aligned and properly lubricated the hardware. It still freaking happens even at that slow speed. What could be causing this?
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    21,112
    Likes Received:
    6,997
    The layer shifting (assuming it is totally random, no mechanical obstructions causing it) almost has to be something loose in the drive train. Bad bearing or sticky rod(s).
     
  3. SoLongSidekick

    SoLongSidekick Active Member

    Joined:
    Mar 6, 2014
    Messages:
    220
    Likes Received:
    68
    OK I'll make sure to check the entire system. What speed do you normally print/travel at?

    The freaking nozzle thing just happened again. It honestly feels like the filament is running up against a lip, and a little pressure pushes it past. Does the stock hotend have a lip inside the heatbreak or something?
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    21,112
    Likes Received:
    6,997
    The defaults -- unless printing flexibles I just use the defaults.

    Nope, there should be a smooth bore all the way through. A partial clog (usually of burned/bad material) can cause issues, but the best way to deal with that is to remove the nozzle (which requires heating it to break it loose) and then after the nozzle is off heat it again and see if it extrudes cleanly. If it does then the nozzle is the issue and if it does not then the heatbreak itself is. With the hexagon getting individual parts (other than nozzles -- those are standard) is a pain. Easier to just replace the hotend.
     
  5. SoLongSidekick

    SoLongSidekick Active Member

    Joined:
    Mar 6, 2014
    Messages:
    220
    Likes Received:
    68
    I'll try a nylon cold pull set when I get home. It sounds like it's just time to install the E3D. I actually like the Prometheus hotend better and think it's a better product, but I have a spare E3D sitting around. I'm going to lose a few millimeters on the z axis but I've just never really liked the Hexagons.
     
  6. SoLongSidekick

    SoLongSidekick Active Member

    Joined:
    Mar 6, 2014
    Messages:
    220
    Likes Received:
    68
    Does anyone know the size of the grub screw used on the filament drive stepper? Mine's like 75% stripped and I know the next time I take it off will be the last time I'll be able to. I'd like to replace it.
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    21,112
    Likes Received:
    6,997
  8. tkoco

    tkoco Active Member

    Joined:
    May 7, 2018
    Messages:
    190
    Likes Received:
    96
    That size would be 1.5 mm. The printer should have came with a kit and in the kit should be the required 1.5 mm Allen hex wrench. If the grub screw is getting torn up, probably need to replace the gear (link posted by @mark tomlinson )
     
    mark tomlinson likes this.
  9. SoLongSidekick

    SoLongSidekick Active Member

    Joined:
    Mar 6, 2014
    Messages:
    220
    Likes Received:
    68
    No, a grub screw is the thing pictured in the image that attaches the extruder gear to the motor shaft.

    1.5mm is the drive size, I need the actual OD size and thread pitch.


    Tried a few cold pulls, they looked pretty normal. Tried 2 prints afterward and both did the exact same thing. Still failing. Someone on the 3D printing subreddit suggested checking the PTFE tube, but the C2 hexagon doesn't have any Bowden tubing inside it right?
     
  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    21,112
    Likes Received:
    6,997
    Let me google that for you :)

    https://www.geeetech.com/wiki/index.php/MK8_Extruder

    Looks like the MK8 (which uses this style gear) is an M3 set screw

    I doubt you are going to get any finer detail than that.
     
  11. tkoco

    tkoco Active Member

    Joined:
    May 7, 2018
    Messages:
    190
    Likes Received:
    96
    With all being said on the matter of the grub screw and the associated drive gear, the drive gear is aluminum and the grub screw is steel. The threads in the drive gear will get ruined long before the grub screw threads do, unless you were using the wrong size Allen hex wrench in the grub screw.

    I still recommend replacing the drive gear (with grub screw). Why set yourself up for a future failure by not replacing the assembly?
     
    mark tomlinson likes this.
  12. SoLongSidekick

    SoLongSidekick Active Member

    Joined:
    Mar 6, 2014
    Messages:
    220
    Likes Received:
    68
    It's not the thread on the grub that's stripping it's the crappy hex socket. I have a nice Proto hex set and the screw just slipped all the time.
     
  13. tkoco

    tkoco Active Member

    Joined:
    May 7, 2018
    Messages:
    190
    Likes Received:
    96
    Fair enough. you will most likely have to buy a lot of grub screws (like a quantity of 100 as an example). If all you need is the one grub screw, it might be easier to get the item posted by @mark tomlinson
     
  14. SoLongSidekick

    SoLongSidekick Active Member

    Joined:
    Mar 6, 2014
    Messages:
    220
    Likes Received:
    68
    Yeah that's exactly what I was thinking. I already have hundred packs of random bolts like M3x22 lying around, I don't need a bag of grub screws too.

    Still no idea why my printer now just completely refuses to print. I swapped the nozzle out to a hardened one I had and the problem persisted. I checked the inside of the hotend while I was swapping the nozzle and it looked clean. I'm completely at a loss. The printer fails every single print I try at between 5 and 30% completion.
     
  15. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    21,112
    Likes Received:
    6,997
    Don't really have enough details in this thread to add too much more specifics, troubleshooting sight-unseen is hard anyway :)
    But I'd go through the usual suspects first (like heat creep). The design of the extruder on the C2/R2 make that a really likely first step-check.
     
  16. tkoco

    tkoco Active Member

    Joined:
    May 7, 2018
    Messages:
    190
    Likes Received:
    96
    Have you tried replacing the fan which blows on the hotend? Perhaps it is not moving sufficient air to properly cool the hotend.
     
    Geof likes this.
  17. SoLongSidekick

    SoLongSidekick Active Member

    Joined:
    Mar 6, 2014
    Messages:
    220
    Likes Received:
    68
    I'm probably just going to swap the hotend for an E3Dv6 I have laying around. I'll love a few mm in the height of the Z axis but not having to fiddle with the crappy stock hotend will be worth it.

    Just gonna replace the hotend with an E3Dv6 and use the included E3D fan. That will knock out just about every potential problem all at the same time.
     
  18. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    21,112
    Likes Received:
    6,997
    As long as you are clear that this is not a drop-in replacement for the hexagon -- there is a thread on the modifications you need to make to the carriage for the E3D.
     
  19. tkoco

    tkoco Active Member

    Joined:
    May 7, 2018
    Messages:
    190
    Likes Received:
    96
    Were you successful?
     

Share This Page