E3D Jamming with both ABS and PLA

Discussion in 'E3D-v6 and Lite6' started by docwelch, Apr 19, 2014.

  1. myk68

    myk68 Member

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    Hi AndersE

    I am beginning to think the same. I thought I had cracked this with seasoning the hotend, cleaning the whole thing inside, buying another nozzle and bringing it down to .7 bore depth.

    however its printed one dalek and jammed again. I would have been better getting another j head or maybe tried the pico

    mike
     
  2. AndersE

    AndersE Active Member

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    I am actually having some success finally. I drilled the .6 nozzle to 0.8mm boredepth but still had some problems, so i tried
    another tip from this forum, and that was to lower retraction speed a lot, down to 10mm/sec.

    Now i have successfully printed about 3-4 hours total without a hickup. Before i could not print more than 15-20 minutes.

    Sadly i drilled the .4 nozzle too deep so i ruined it. I will try the .25 next.. after i have printed more to be sure it worked.
     
  3. myk68

    myk68 Member

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    I did the same with my .4, drilled it through. luckily had another on order. This one Ive taken down to .76 but still having issues

    I have success with seasoning the hot end but only works for one small print and then jams again.

    my retraction is down to 20mm/sec but i'll try lower from what you said
     
  4. Eaglezsoar

    Eaglezsoar Administrator

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    You should be using a hand drill, not a power drill.
    You can just twirl the bit with your fingers, slow but effective and you don't ruin the nozzle.
     
  5. Josh

    Josh Administrator
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    Hi AndersE,

    Can I just ask you to describe in a bit more depth the setup that you are using? Having taken all these steps it seems like there may be some other factors at play.

    Printer:

    Bowden/Direct?
    Extruder Type?
    How does the filament look after the hobbed bolt? Is it crushed so that the filament is out of round?
    Cooling - is the fan over the HeatSink running continuously? Does the bottom fin of the HeatSink feel cool to the touch?
    Material - Manufacturer, Colour and true diameter, measured with callipers in a couple of places.
    Printer type?
    Thermistor config in Marlin?

    Slicer:
    Printing temps
    Retraction lengths / speeds
    etc..


    We will get your E3D HotEnd working, even if it means swapping out your metal parts.

    Cheers,
    Josh
     
  6. myk68

    myk68 Member

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    hi eaglezsoar

    I was doing it by hand in my fingers. must have got to carried away because the next i knew was pop, the drill bit is out the end :oops:

    I am currently trying a print that has worked once with PLA then not worked again. this time I am trying a bit of ABS. first time i have used this so results may not look great but its the jamming I am interested with. I seem to think i read on here that pla does not jam as much if you also use ABS at times.?

    we will see

    Mike
     
  7. AndersE

    AndersE Active Member

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    Sure.

    I also handdrilled with fingers, but as Mike i was also too eager...this was before i got the heat/insert PLA/cool and pull method working :(

    Direct
    Original k8200 geared
    it has ridges from the bolt, but not squished.
    Fan is running
    Bottom fin is not hot, feels cool.
    Material: makerbot 3mm green abs, vhite and fluroecent yellow PLA also from makerbot i think.
    I have run out of prime filament, so this last successful prints is done with homemade filament
    from pelletized Playstation 1 pure ABS shells ;) on my homemade extruder. Diameter is between 2.8 and 2.9mm

    Printer is Velleman K8200
    Thermistor config 5 as is original on k8200 also.

    Slicer is Simplify3D 2.1.0 which is blazingly fast in slicing. Even much much faster than Cura is and the snail repetier/slic3r.

    Temp 220c
    retraction working so far is 0.6mm at 10mm/sec.
    speed max 75mm/sec
     
  8. AndersE

    AndersE Active Member

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    I should add that extruder is calibrated and also PID. Temp in range of one degree.
     
  9. Sanjay

    Sanjay Administrator
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    Makerbot PLA apparently likes it hot - you might try bumping it up as much as 20C.
     
  10. AndersE

    AndersE Active Member

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    Makerbot PLA did i print at 190c with original hotend, on e3d i have tried up to 220.
    The 220 i wrote above is for the PS1 ABS, but have tried up to 245 also, but it prints good at 220.

    I am trying 0.25 nozzle now.

    Would it be possible to get a replacement 0.4 nozzle on warranty?
     
  11. myk68

    myk68 Member

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    Well No Jams with ABS, though getting it to stick is a bugger. :x

    once i'm finished playing i will load the pla again and see if it jams again
     
  12. AndersE

    AndersE Active Member

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    Grr.... the 0.25 nozzle blew open after 20minutes, it seems i drilled too much so the walls got weakened :(

    Getting a bit tired of this bull...

    Swapped back to original hotend (which i have never cleaned or had any problems with), felt the joy of printing again.

    Will continue testprinting with 0.6.
     
  13. milosonator

    milosonator New Member

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    I'm having a lot of the same issues as other people here. Basically I have tried over 10 prints, only 1 succesfull so far: all due to jammed PLA. What is going on? I have a E3D v5 3mm.

    I'm using 3mm PLA in a bowden setup, already tried different types of PLA, doesn't seem to make a difference. How can I prevent these jams? Could it be that my nozzle bore is too long? Shorter retracts? (3mm right now)

    Please advice!
     
  14. Andy3D_TF

    Andy3D_TF Member

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    Hi everyone,

    Just like to add my grain of salt - after getting this same jamming problem and opening up the hot end, I observed a "sheath" of pla on the inside of the heatbreak tube, a few mm long, and after reading all this thread I think the problem may be of the PLA warming in the heatbreak enough to go soft, and this together with a VERY efficient heat sink causes a "competition" in the area where the hotend softens and the heatsink hardens the filament (and the metal around) - this softening/hardening portion eventually grows large enough so that the now very tight fit causes enough friction to block completely... The extruder does not now have enough strength to push this (sticky- it's pla) block thru, but if I stop, retract at least 10mm and then push thru again, bingo! It starts extruding again.
    I think the oil seasoning may help a bit to stop sticking, but, as mentioned in another thread, a heatsink fan shroud that also is directed at the heatbreak would possible help more, as would reduce the heat zone where the portion of filament "grows" the blockage. Also I think that boring out the nozzle is actually bringing that area slightly further down, enough to help avoid (for most people) this issue. Maybe adjusting the exact height of the heatbreak in relation to the block may help too. I would be very interested in know the measurements from Airtrippers pressure sensor during the run up of this issue.

    I came to this conclusion for various reasons:
    When it blocks and I completely remove the pla, the extruder can retract it easy enough, and when the melted point comes out, it almost always has become very slightly fatter - the "sheath" that I had observed when opening up the hotend that sometimes stays where it forms - possible could actually be PLA that has pushed back up the edges of the filament and solidified having left the melt zone.
    I have a large delta with Bowden, and in my desperation have adapted a "hanging extruder" setup (the extruder is tied thru elastic to the tower carriages, allowing it to hang about 20cm above the effector) to reduce the Bowden length (thinking that the 1.2m tube was causing too much friction), and this arrangement causes the extruder to "twitch" freely when the clicking sets in (it's hanging mid-air after all!). Well sometimes have even noticed a small "jump", much larger than the barely perceptible "twitching" when the filament snaps back the extruder motor, WHEN I do that 10mm retract - like if the blockage was caused be a plug that just got freed all of a sudden - that's when I can then start extruding again.

    I'll be trying this week the revised heatsink fan shroud that includes the heatbreak from the other thread, so I'll get back to you if it works ;-)

    If this is the issue then the question is reducing the heatbreak zone to make sure the area where the pla can melt, re harden, reflow, whatever, is as short as possible, to maintain the pressure created by this area to less than that which the extruder can cope with.

    Cheers!
    Andy
    :)
     
  15. Eaglezsoar

    Eaglezsoar Administrator

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    You make some interesting observations and it will be interesting to see if your "fix" actually works for you.
     
  16. AndersE

    AndersE Active Member

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    I have been really successful in printing a lot now with drilled 0.6 nozzle.
    My new favourite material to print is nylon. I have been using grasstrimmer nylon of different sizes down to 2.0mm in my original k8200 extruder. No warping to talk about, and strong as hell plus flexible.

    It prints really good and is not difficult at all. No heated bed, only little fancooling and gluestick on the glassplate.
    Moisture problem in the filament have i not had any problems with either. But i have it in a box with "torrboll" (drying stuff).

    Grasstrimmerwire comes in lot of nice colours. Blue, green, signalred, orange, yellow, transparent etc..
     
  17. Josh

    Josh Administrator
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    Hi Andy,

    Your have made some really interesting points about what happens at the heat break. This is what makes it so important to a) reduce the length of this region as much as possible (as you mentioned) and b) focus on the what risks making the filament stick at this point. The seasoning does make a big difference in this regard, and in v6 we have done some really cool things with the machining process we use to ensure the best possible internal finish.

    Regarding the sheath, I can't imagine molten filament flowing back up into the cold region, do you think this could maybe be caused by a retraction?

    How have you gotten on with the new shroud?

    Josh
     
  18. AndersE

    AndersE Active Member

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    Josh:

    I have done a lot of testing lately. I had success printing ABS after the drillout of my 0.6 nozzle, but still a lot of sticking with NYLON printing.
    The bore of the heatbreak is a little bigger then the filament , that is normal. The buildup of backpressure forces the molten filament back and up between the heatbreak walls and the filament, upto the point when the extrudermotor can't cope and then starts to eat filament.

    The solution, or part solution is to use big (10-15mm) retracts of filament to release the backpressure. When the filament is retracted, the remaining molten filament collapses down back into the meltzone just in time for the filament to return and push down.

    This way i can print small objects (5-10cm) with ok success. But as soon the loops get long (bigger objects with less retraction points) i get problems again, but as soon a retract has been done it prints again.

    I notice that when i print large parts though, the big retracts don't come often enough, so i get uneven filament on the objects.

    If NOT using ANY retraction = sure JAM almost instantly.

    If not printing anything, just extruding into thin air, it is very noticeable.
    A couple of cm's good extrusion, then a short break when the pressure is to big, and filamentfeeding stop, but as soon the pressure has pushed out the melt the filamentfeeding starts again (even if the motor have started to eat filament)

    It "seems to me" the meltzone is too small or the nozzlediameter is to small for the amount of filament coming in.
    (Yes i have calibrated the extruder, and correct filament diameter set)
    OR to much filament is coming in so the meltszone/nozzle don't have enough time to melt and squeeze.

    This is just my thoughts after 2 weeks of nylon printing.

    I am actually thinking of buying the new v6 also just to try it out , even if i am far from satisfied with v5.
     
  19. Andy3D_TF

    Andy3D_TF Member

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    Hi Josh,

    Sorry, redesigning my print head just now, hopefully will be able to try out within next couple of days - if it doesn't work as-is, I've already designed a fan shroud that mount the fan horizontally at the top, so more air should get to the heat break...
    The sheath could well be from retraction - with the 1.2m Bowden ID been using 6-8mm, and when I cut it down to 20cm been using 2-4 - my new design will mount a nema14 direct drive on top of the kinematic magnetic tool head, so will be able to reduce retraction a lot more... ;-)

    I'll try and remember to post my results on how it's going...


    PD. On the theme, I'm also trying to adjust the amount of thread screwed into the heatblock to make contact as large as possible - right now the gap between nozzle and block is almost not visible, and I was even considering putting thermal paste in this gap (with a LOT of care and a very good clean up afterwards to avoid getting it anywhere else) as it is clear that the nozzle/block thermal bridge is very important and that less contact between these parts will also cause a colder zone at the bore - just trying to eliminate secondary causes ;-)
     
  20. ZeRoCoOl

    ZeRoCoOl Member

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    I faced the same issue initially. The problem i found was the heat travel up the heat break and "cooled" the heat filament causing it to jam. Tried cleaning with oil, pulling new filament to "clean" the internals.

    Have done a few changes:
    1) used a new print cooling fan with a heat break cooler, and no issue since then. Have successfully printed a 8hr print (flower pot @ 0.1mm).
    2) Hotend at 195 degress (original 185)

    Credits goes to respective owners.
    Print cooler: http://blog.reprap-india.com/2014/04/03 ... al-hotend/

    Hope this helps :D
     

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