Clogging after 40 minutes or so

Discussion in 'E3D-v6 and Lite6' started by Sniglet, Mar 12, 2014.

  1. Sniglet

    Sniglet Member

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    I've got a 3DR printer, with your e3d hot end, 1.75, .35 orifice, PLA running at 190 (and some Makerbot filament I've run at 230...and some ABS I've run at 245 with a cold bed and warpage)

    I've got the fan running constant on, and another fan running on the Bowden to keep it cool, but I can't seem to get any print that runs longer than 45 minutes or so. When I pull the filament and snip off a little bit of the end, it extrudes well again. 190 seems a little cold as it extrudes MUCH easier at 200-205, but either leads to an eventual plug.

    Suggestions? This thing is _SO_ close to being dialed in it's driving me nuts!
     
  2. Eaglezsoar

    Eaglezsoar Administrator

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    Is your fan shroud lined up so that it is even with the bottom fin on the E3D? This is very important.
     
  3. Sniglet

    Sniglet Member

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    Yup. :(

    The only largish successful print to date had me hand feeding the filament to babysit it. The Bowden is capable of cramming up the filament just past the hobbed bolt when things back up, so it's not a grip issue. I spent a long time thinking it was the Makerbot filament, but the replacement stuff is doing the same thing.
     
  4. Eaglezsoar

    Eaglezsoar Administrator

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    When you use ABS do you get the same results?
    When you say you hand feed it does that mean you release the filament from the hobbed bolt and push it through by hand?
    And lastly, have you done a calibration on the extruder so that the E-Steps are what they should be?
     
  5. Sniglet

    Sniglet Member

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    Abs doesn't clog, it just doesn't stick to the non-heated bed. Hand feeding meant I was loosely feeling the filament and giving it an additional push as necessary to keep going. You can feel if the back-pressure on the filament is causing the hobbed bolt to slip and give the tensioner a quarter turn, then the filament stops slipping (until the failure listed above).

    I've calibrated the e-steps, 10mm is 10mm, but I'll also find I need to adjust the extrude rate in Repetier so that the fill doesn't squish up higher than the perimeter, giving the head something to catch on. I'm getting excellent initial fill, it's really dialed in and working fine for the first 30-45 minutes.

    Then it does this: https://drive.google.com/a/millertwinra ... sp=sharing

    The extra drool up top is where I fixed the filament, but the print level was too high to really continue the print.
     
  6. Eaglezsoar

    Eaglezsoar Administrator

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    I'm sorry but I am out of ideas pertaining to why you are experiencing clogging.
    The fact that it can print fine for 30+ minutes just confuses the matter.
    Perhaps Josh or Sanjay may have an idea why this is happening.
     
  7. Sniglet

    Sniglet Member

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    Yeah, I'm pulling my hair out...it could be that there's not a large enough gap in the heat break...the fan's running. Perhaps I need to drop it a bit to blow on the Stainless Steel part, perhaps I need to up the extrude rate to reduce the time the filament spends in the hot zone...I'm really at my wit's end with this as the printer seems to be doing all the right things, otherwise. I have have MOUNDS of failed prints that fail a dozen or so layers in (depending on volume printed and corresponding to more than 45 minutes or so).
     
  8. Eaglezsoar

    Eaglezsoar Administrator

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    I would NOT lower the fan shroud so that it blows on the heat break. It should be even with the bottom fin.
    Your idea to adjust the extrude rate might be helpful.
    There are users on the seemecnc forum that have problems with PLA also but they are a small minority of E3D
    users, the vast majority print PLA with no problems. They never have found a solution for the small numbers of users that
    have the problem, I wish I could give you a solution but experimenting with different settings seems to be all you
    can do at this point. Best of luck to you.
     
  9. Sniglet

    Sniglet Member

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    I'm frustrated with some of the idiosyncrasies of a delta printer and plan on building a cartesian with the parts, but before that happens, I have to be able to print the parts.
     
  10. Eaglezsoar

    Eaglezsoar Administrator

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    With your particular problem you may have to add a heated bed and use ABS to print the parts.
     
  11. Sniglet

    Sniglet Member

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    I've lowered the fan shroud, I've seasoned the nozzle with oil...and still had prints fail. I started printing printer parts for an Ingentis printer I want to make next and it's printing perfectly. I suspect the issue is tuning retraction and possibly temp as I've lowered it to 180....but I'm suspecting retraction.
     
  12. Tiguu

    Tiguu Member

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    I am also having same problem. I was focusing on the Extruder and E-steps but I read in Google+ 3D Printing that you need to have cooling between the heat break and heater block. Once I have everything setup again, I will try it.
     
  13. Eaglezsoar

    Eaglezsoar Administrator

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    Please let us know the results of your tests.
     
  14. Sanjay

    Sanjay Administrator
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    Hi Sniglet!

    Retraction is a really common jamming point for bowden - too much retraction is often the cause. You might try turning off retraction entirely and do some prints to see if it is the point of failure.

    If you can print fine with retraction disabled then you should try gradually increasing your retraction starting at 0.5mm and working upwards by 0.2 to 0.3 mm at a time. You should work up to a point where you are getting clean prints with complete reliability. If not then something is wrong elsewhere - it's unlikely but perfectly possible that there is a manufacturing defect with the hotend, in which case we will gladly replace it.

    I hope you get running soon, let us know how you get on!

    Sanjay
     
  15. Tiguu

    Tiguu Member

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    I no longer have stuck problem, see my test result in "Airtripper Extruder Skipping".
     
  16. reprap_sam

    reprap_sam New Member

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    Hi
    I'm facing similar issue with the E3D v5 1.75mm bowden extrusion.
    Print starts good but hotend gets jammed after 20 mins or so. I'm printing PLA with 190-200C, speed is set very low. To get it start printing again have to retract complete filament out of bowden, cut 10mm and reinsert it.
    Retraction is set to default 1mm, tried with 0 as well but faced same issue.

    Could anyone suggest ideas to get consistent prints for entire duration of job?
     
  17. Sniglet

    Sniglet Member

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    Yeah, I've had 4 and 5 hour successful prints now with the original e3d...it ended up being WAY too aggressive retractions.

    In KISSlicer, I reduced suck/prime to .25 and things got a LOT better. I'm pretty sure there was some other tuning on the hobbed bolt side, too, to keep things going.

    Lastly, there was an issue with the nozzle being too close to the glass, that caused filament to back up and jam at the hobbed bolt end.
     
  18. Josh

    Josh Administrator
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    Cheers for your input Singlet - having the nozzle too low can cause the HotEnd to jam, the internal back-pressures that are reached are actually very high, and certainly enough to cause a jam, or the hobbed bolt to slip.

    reprap_sam, you may want to increase the temperature a little, up to say 210C. Also make sure that the bottom fin of your HeatSink is cool - should be barely detectably over room temp.
     
  19. mhackney

    mhackney Well-Known Member

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    I'd like to add - even more critical than retract length is retract SPEED. I did a series of tests and reported them on the SeeMeCNC forum about this on my Rostock with Bowden. Slow down the retract to 20mm/s and then try again. Fluids may have non-Newtonian behavior - a property called "thixotropic". I suspect based on over a year's worth of observations and tests that PLA melt exhibits this to a greater degree than ABS. So, quick moves like a rapid retract and prime will actually cause it to "solidify". Do a lot of these in a short time and you get a phenomenon I call "hydraulic blocking". Slow down the retract speed and see what happens. I am now running 1mm retract at 20mm/s and 3mm Z lift and not getting stringing at all and LOOOOOONNNNNGGGGG print times with no plugging.

    I did have a plug yesterday for the first time in months. When I disassembled the hot end, I found that the PLA plug was very hard, almost glass like. I'm not sure if it got overcooked (but I run at as low a temp as possible, somewhere around 185°C for PLA) or if I had some contamination in or on the PLA. I'll keep my eyes open for this.
     

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