Jammed, clogged, cleaning - FAQ?

Discussion in 'E3D-v6 and Lite6' started by UlrichKliegis, Dec 31, 2015.

  1. UlrichKliegis

    UlrichKliegis Well-Known Member

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    Hi all,
    amidst a very productive printing session, that dxxxed PLA filament from some amazonic source got stuck in my hotend, well, in my printer's E3D-V6 hotend. After taking it apart and heating the block, I was able to carefully unscrew the nozzle. It's cavity was empty, the nozzle itself looks like a child boy's nose, dense with transparent material, nothing to worry about.

    The blocking, though, is obviously a few millimeters upwards in the heat insulator, that piece of delicate fine mechanistry that connects the heating block and the cooling part. The filament's path is locked with material. How can I get that out there without scratching or deleting the insulator? I've got some fine drill tips (1.7mm among them, pressurized air, and more. What is recommendable? Also with the aim of having a well functioning device again.

    I guess it got stuck there due to a somewhat too enthusiastic thermal regulation. I calibrated the PID parameters, but I found already that this new filament shows a different behaviour compared to the stuff I used so far - obviously, the dealer / maker went belly-up. Marlin's screen showed underswings of up to 2° C, maybe enough to hit on that steep slope between liquid and stuck.

    Is there some faq where this sort of problem is discussed already? I can't imagine that I am the only one experiencing this.

    Thanks in advance, and a very happy and sucessful 2016!

    Cheers,
    Ulli.
     
  2. elmoret

    elmoret Administrator

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    Best way to remove PLA is a heat gun. Best way to remove ABS is to soak in acetone.

    I doubt the jam was caused by a 2C swing. What are your retraction settings? Are you using thermal paste?
     
  3. UlrichKliegis

    UlrichKliegis Well-Known Member

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    Fixed.

    After taking everything apart, I left only the insulator in the heating block and heated that to about 230 °C. Then I very gently pushed in a 1.7mm drill bit, turning it carefully into the molten mass. After pulling out some blobs of the blocking material I was able to push the drill (manually!) quite through. The insulator's inner lumen felt and looked clean again after that.
    Putting together everything again showed that some screws and nuts might have rattled loose a bit in the hundreds of hours of serviceless operation that the hot end has passed so far.
    Everything looked fine then, so, power on, heat up, start printing - a clean, much cleaner than before, sound, a better looking first layer, ruinning like a swiss clock again. The morale: Keep your hotend tidy and your nuts tight! ;) I'll keep my fingers crossed...

    And the search for the reason of the jam / clog? Can't say for sure, but I assume the combination of some detritus and debris buildup in the filament path, combined with or caused by some loose connections, maybe a little weak force on the idler bearing in the extruder, mind you, the whole thing a very heavily modified OrdBot, using a Buldog Lite extruder - which still shows in the pretty rustical surface, but better times are to come here too, there should be some parts in the BigBoxesBox that I expect real soon now.
     
    #3 UlrichKliegis, Dec 31, 2015
    Last edited: Jan 1, 2016
  4. UlrichKliegis

    UlrichKliegis Well-Known Member

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    Meanwhile, I also don't believe any more that it was that underswing. See my report on the repair. I changed two major things accidentally at the same time these days: New filament make (making some temeprature adjustments necessary, the new stuff needs about 7 degresse more than the previous one to achieve the same flux properties) and a move from Slic3r to Simp3D (the latter not yet final).

    I did not change the retraction parameters in Marlin, but I am not sure what S3D does to the dynamic parameters that are NOT user selectable, for example the acceleration during retraction.

    I transferred everything possible from the Slic3r setup to S3D, but they don't have a place for every variable. More on that in a different report shortly.

    P.S.: Seems the E3D servers has a hickup this last evening of 2015. Too much BigBox campaign champagne?
     
    mike01hu likes this.
  5. UlrichKliegis

    UlrichKliegis Well-Known Member

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    Unfixed, unfortunately. Same error, filament clogged and stuck in the lower insulator part after about 3 hours of flawless printing.
    It happened during a linear infill.

    Retraction parameters:

    Retraction length: 1 mm (in terms of filament)
    Retraction speed: 40 mm/s
    Minimum path after retraction: 1 mm

    No thermal paste use.

    What is genereally recommended for these parameters for 1.75mm PLA in an E3D-V6?
     
  6. elmoret

    elmoret Administrator

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    Those retraction settings are fine, but it is recommended to use thermal paste on the threads between the heatbreak and heatsink if printing in PLA. It is possible your ambient temperature are right on the borderline for PLA jamming.
     
  7. UlrichKliegis

    UlrichKliegis Well-Known Member

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    OK, I'll apply a droplet when repairing the thing again tomorrow. The other thing that I thought about is the placement of the cooling fan's holder box. Now it sits just between the upper- and lowermost cooling plate, it would make much more sense, though, to place it a wee bit lower so that the underside of the (most important) lowest cooling disc is also exposed to the airstream. Should make it much more efficient.
     
  8. mhe

    mhe Active Member

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    PLA also dissolves in Tetrohydrofuran. You can not only use it for cleaning but also to give parts that glossy finish similar to ABS when you expose it to acetone vapor. Tetrahydrofuran can be had at Amazon, but be careful, that stuff is not very healthy, so only work with it outside or very well ventilated areas and don't inhale the fumes, use breathing protection if possible.
     

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