Filament keeps retracting but not extruding

Discussion in 'Titan' started by Soynuts, May 29, 2016.

  1. Soynuts

    Soynuts Member

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    I have had a titan for a couple of weeks now and have been having a ton of trouble with it. For short prints (about an hour or less) I tend to have no problems, but for longer prints it always gets to the point where the filament constantly retracts but never pushes forward. When I stop the print and manually rotate the gear on the titan, the filament moves forward and extrudes out of the nozzle, so I'm at a loss as to why it keeps retracting backward but not forward after a couple of hours of printing. And it's not always consistent, sometimes it'll happen after 2 hours or after 4 hours on the exact same print file. I may just switch back to the EZStruder if I can't resolve this.

    Printer: Rostock MAX
    Filament: MG94 (extruded with a filastruder, ~1.70mm)
    Hotend: e3d v6 lite
    Temp: 225*C
    Slicer: Simplify3D
    Retraction: 5mm
    Retraction Speed: 30mm/sec
     
  2. danzca6

    danzca6 Well-Known Member

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    Do you get any odds noises? Is the stepper overheating? Does the filament seem to grind? Just trying to think what else can be happening at the time of the failure.
     
  3. Soynuts

    Soynuts Member

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    Looking at the filament from the last failure, there is no grinding. Just the normal teeth marks you would expect from normal extrusion and retraction. I do notice that it sounds louder when retracting when compared to extruding. I also have heatsinks and a 40mm fan on the stepper motor to prevent overheating.

    This is the stepper motor currently installed: https://www.seemecnc.com/collections/parts-accessories/products/nema-17-high-torque-stepper-motor

    I do have one of these motors lying around if it's worth trying out to use instead: https://www.seemecnc.com/collections/parts-accessories/products/nema-17-short-can-stepper-motor

    I did notice looking at the "Titan not extruding" thread that my hob has smaller teeth as shown in this post: Titan not extruding correctly. Mine looks more like the one on the right than the one on the left. But wasn't sure if that was what my problem was since mine does extrude when it's actually pushing forward. It's like it slips when trying to extrude but doesn't seem to slip when retracting, which seems odd.
     
  4. Dr Jeep

    Dr Jeep Well-Known Member

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    I've had similar problems before (not on a titan but on a E3D V6) when my retraction distance was too high, and in fact 5mm does seem quite a bit and more than I've run on ABS. After the "jam" if you pull the filament right out then how does it look ?
     
  5. Spoon Unit

    Spoon Unit Well-Known Member

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    The E3D assembly guide states somewhere that no more than 2.5mm should be configured for retraction. It sounds as if you're running into the situation where a deformed filament end is pulled out of the hot end and won't go back in due to deformation. This would be hit and miss I guess and hence why you're running into unpredictable results. Definitely lower your retraction value in the first instance.
     
  6. Soynuts

    Soynuts Member

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    The E3D lite assembly instructions actually say bowden systems should not exceed 8mm in retraction and that 5mm is a good starting point. I actually have to use 7mm to get no stringing, but with Simplify3D and the coasting option, I was able to bring it down to 5mm.

    And that is the odd part, it is not jamming. The filament is actually retracting all the way out of the hotend and out of the extruder. It's like it stops pushing it forward and is only able to push it back. But if I push that same filament all the way back in execute an extrude command of 50mm, it pushes filament out of the nozzle without trouble. It's just confusing me how its able to push it completely back out but seems to just completely stop with any forward extrusion.
     
  7. Spoon Unit

    Spoon Unit Well-Known Member

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    From http://wiki.e3d-online.com/wiki/E3D-v6_Assembly#Usage_Guidance
    • Excessively long retractions will cause issues by dragging soft filament into cold areas. E3D-v6 hotends need less retraction than most hotends. For direct extrusion systems you should use anywhere from 0.5mm-1.0mm, for bowden systems you might want to go up to 2mm. Retraction beyond 2mm is likely to cause issues.
     
  8. danzca6

    danzca6 Well-Known Member

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    But if he has the Lite and using Bowden, then he is right about the assembly instructions for the Lite saying 5 mm to start.

    http://wiki.e3d-online.com/wiki/E3D-Lite6_Assembly

    Excessively long retractions will cause issues by dragging soft filament into cold areas, because of the PTFE liner however Lite6 can cope with quite aggressive retractions without sticking. For direct extrusion systems you should use anywhere from 0.5mm-2.0mm, for bowden systems you might want to go up to 6mm. Retraction beyond 8mm should never be necessary. A good starting point for direct systems is 1mm, and 5mm for bowden setups.​
     
  9. danzca6

    danzca6 Well-Known Member

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    You have heat sinks and fans on the motors? Or do you mean the stepper drivers on the Rumba board? I was thinking of the actual Nema 17 extruder stepper motor.
     
    #9 danzca6, May 31, 2016
    Last edited: May 31, 2016
  10. Soynuts

    Soynuts Member

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    That is correct, I have them on the Nema 17 extruder stepper motor. I have a 120mm fan that blows over my rambo board.
     
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  11. danzca6

    danzca6 Well-Known Member

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    Well then that's hard core cooling. Rules that out. :)
     
  12. Soynuts

    Soynuts Member

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    Received a hob replacement for the titan and now my weird retraction problem has gone away. Now just dealing with an odd jamming issue that isn't related to the titan.
     

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