Jamming

Discussion in 'E3D-v6 and Lite6' started by johnrygg, Jun 13, 2014.

  1. johnrygg

    johnrygg Member

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    Hello All, got my v6 installed , I got it because after 4 months of care free printing with the v5 I all of a sudden was getting horrible jams every other print. so much so that I had to disassemble the print head to clear the jam. in the process I broke off the heat break tube in the print head.

    so I figured I would solve all my problems by just getting a completely new v6.
    but now my v6 is starting to jam after just a couple prints. at first I thought it was just cheap filament
    causing the jam, but I have tried 3 different filaments with the same results.
    the nozzle is not clogging the jam seems to be in the heat break tube.
    any ideas ? how do you season with oil?
    I may try the oil on a sponge before to lube the filament.
    not sure why all of a sudden this started with the v5 and now the v6...




    thanks John
     
  2. greenalien

    greenalien Member

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    As far as I know, there are 3 main causes of jamming that can occur with any hotend - one or more of the following:
    a) Hotend is too cold, or isn't being heated fast enough to keep up with your feed rate. Is the hotend temperature dropping as your print proceeds? Closely related to this is :
    b) Feed rate is too fast - have you calibrated your extruder? Is your filament exactly to the set size, and is that size consistent for the whole reel?
    c) Hotend above heat break isn't being cooled enough, so filament is melting prematurely.
     
  3. GlitchE

    GlitchE Member

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    I have exactly the same problem.
    My PLA filament (ColorFabb, Faberdashery 3mm) gets stuck in the heat break.

    I've noticed that's the lower 8mm on heat break inside significantly smoother than the upper part.
    As if only the lower 8 mm were polished. Is this normal? This can be seen with the eye easily.
    Oil helps, but for me that is not a solution.
    The problem I have with bowden and direct drive.

    a photo of the exact problem is not possible with my camera.


    http://imageshack.com/a/img850/394/ocbk.jpg
    http://imageshack.com/a/img823/4479/ps896.jpg


    I hope this helps to resolve the issue: (


    GlitchE
     
  4. Josh

    Josh Administrator
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    How are you getting on johnrygg? Cheers for your input greenalien.

    GlitchE, we have paid very special attention to the surface finish at the lower side of the HeatBreak which is the most important region in ensuring reliable extrusion, so it is normal to see a difference in surface finish between the two ends. From your photograph it seems like the filament has had the chance to melt and swell which means that the HeatSink is probably too hot. If you heatsink is warm or hot to the touch (even on that bottom fin closest to the heater block) then something is wrong. The included 30mm fan and duct should absolutely provide enough cooling. Try feeling the heatsink at the point where a print jams.

    This advice also applies to johnrygg if you haven't already sorted your issues.

    The next thing is to look for areas in your system where the filament isn't "guided" or properly constrained from side to side where it could be bending slightly and absorbing force from the extruder. When printing in a Bowden system also make sure that your couplers have the tubing fully inserted into them and the tubing locked into place by pulling up on the collet while pushing the tubing into the coupler.

    Please provide as much detail as you can on your setup so that we can get to the bottom of what is causing this - there are a lot of variables in the system!
     
  5. johnrygg

    johnrygg Member

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    Hello , got everything cleaned out and tightened up as much as possible. another forum suggested canola oil on the filament . I am giving that a try for a test. I have been able to print a few things out.
    I have a direct drive system and not sure why I suddenly started having the issues.

    I am running a long print tonight so we will see how it works.

    Thanks for your help
    John
     
  6. bluemoth

    bluemoth Member

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    Hi,

    I'm having similar jamming issues. I have a Prusa Mendel i3 with a Wade extruder. I use 3mm filament.

    I dismantled the head and see similar effects to the photos posted by GlitchE. The PLA seems to be pushing back up the heatbreak by 7-8mm and swelling to 3.3mm. The fan is continuously running and the heatsink fins appear to be cool but I haven't measured it at the exact time if jams. I moved from a 0.4mm nozzle to a 0.8mm nozzle and this improved things but it still jams after a while. I've also tried different filaments from different suppliers.

    On one dismantle I measure the 0.4mm bore length from the length of the extruded remains and it was around 1mm long. Is this OK?

    I've given up for the night but thought I would post my experience. It is highly frustrating. Maybe next time, I'll systematically test things and take photos. If you have any advice on a systematic testing approach, that would be good.

    Cheers, Duane.
     
  7. johnrygg

    johnrygg Member

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    Well I jinxed myself. had another Jam this morning.

    Still getting jammed at the heat break tube. I can take everything off heatsink and nozzle and see the filament sticking out of the cold end of the heatbreak tube.
    I have to heat the heater block up to 300 c without the nozzle on to get the filament out, and then it takes quite a bit of force to get it out.
    It seems like it needs a separate cooling fan for the gap between the fins and the heater block.
    like this web page is suggesting
    http://blog.reprap-india.com/2014/0...in-all-metal-hotends-e3d-v5-all-metal-hotend/
    not sure if the oil is helping , but now things are a bit messy :(
     
  8. johnrygg

    johnrygg Member

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    Very frustrating. I had such good luck with my v5 up for months until 2 weeks ago then it started jamming. Did not change any settings or filaments. Now after swapping everything out for the v6 I am having the same issues instantly.

    the Heatsink is staying cool and the fan is running all the time. but the filament is definitely swelling up and getting stuck in the heat break. . after I got it unstuck I ran some nylon through it and let it cool. then turned my heater back on and kept tension on the nylon so it would let go when it warmed up enough.
    the PLA that got stuck was black and the nylon is white so when it let go I could see it had 2-3 mm of black pla stuck to the end of the nylon. it seems like the PLA is backing up in the heat break tube.

    the strange part is that it jammed after only about 15 minutes of printing, it did not even finish the first layer.
     
  9. bluemoth

    bluemoth Member

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    johnrygg, have you tried moving the fan down a bit so there is some airflow under the first fin and around the heatbreak stem? I might try this tonight. I might also try some ABS.

    BTW, what size filament are you using?

    For me it sometimes jams just after the first layer or after the first print. I wonder is it's because it is cooled and then reheated.

    Cheers, Duane.
     
  10. johnrygg

    johnrygg Member

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    Good Idea , I will see if I can move the fan down that far. I am printing with 1.75 PLA with a .4 nozzle.
    I have the first layer printing at 195c and slower then the rest of the layers.
    the rest of the layers I have printing at 190c . but have had jamming at all layers.

    It sounds like E3D needs a fan shroud that vents under the last fin
     
  11. Josh

    Josh Administrator
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    John,
    Given that your v5 suddenly stopped working I would be inclined to say that there is something else wrong in your system. Can you tell us more about your printer, what extruder are you using? Can you take some photos of the Hot-Side of the HotEnd (Nozzle, Heater Block and HeatBreak). So that we can get an idea of your idler tension and what your drive gear is doing to the filament, can you also take some photos of the drive hobb and the filament after it has passed through it. If you could also measure it after it has been through the extruder that would be helpful..

    Also, can you PM me where you brought your HotEnd from?


    GlitchE,
    How are you getting on?


    Duane (bluemoth),
    The bore length is a little on the long side, but within tolerance. Can you let us know how you get on with ABS and we will go from there. Sanjay and I are working on a formalised testing procedure which we will get posted ASAP.
     
  12. GlitchE

    GlitchE Member

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    Hello,

    i have an sparklab and an mod. rostock delta.

    The sparklab works with an direct drive v6 + bulldog XL extruder (3mm). The rostock with an bowden + bulldog XL extruder(3mm).

    I polished the inside from the heat break with fine sandpaper. A great improvement did not bring that unfortunately.
    Today i will try to put the fan a little bit down.

    In the next days i will try to build the rostock with an 1,75mm v6 combination.
    I hope through the small surface of the material the problems are loosened.

    At the moment i have no idea.


    Luka
     
  13. Josh

    Josh Administrator
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  14. Eaglezsoar

    Eaglezsoar Administrator

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    I did one of the beta tests on the V6 and I printed for hours and hours with all sorts of different PLA without one plug.
    The only thing that I can think of for you is to raise your temperature from 195 to 205-215. I know that PLA should print
    at 195 but I used 205 on mine with absolutely no plugging.
     
  15. bluemoth

    bluemoth Member

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    Hi Josh,

    I couldn't get permission to add details to the google doc.

    I'll try raising the temperature and also ABS tonight. My work has a temperature imaging device I might be able to borrow. Will images of the temperature profile of the hotend be vaulable?

    Cheers, Duane
     
  16. Josh

    Josh Administrator
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    Ooops - sorry about that, permissions fixed, so do have another go if you have time!

    Cheers,
    Josh
     
  17. bluemoth

    bluemoth Member

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    So I did some tests tonight and I could consistently get blocks.

    I would extrude 30mm, then wait about a minute, where filament would ooze out, and then extrude 1mm at a time to see if there is a block. Most of the time there was, in which case, I would retract the filament 20mm (I could hear the block get squeezed up the heatbreak wall), then extrude 30mm immediately which would clear the block.

    I repeated this for 205C, 215C, 225C and 235C. I got a couple of blocks at each temperature except 235C, which there was none form 3 tries. I reduced it back to 215C and after 3 trials I couldn't get a block.

    Then I decided to try a print. I turned off the extruder for about 30 seconds, the temperature dropped to around 200 before I turned it back on. When it got up to 215C, it was blocked again. I can tell right from the first 1mm extrude, you can feel the filament is not moving.

    Then I wrote the above paragraph, then went back and it was free again. This is after some oozing.... I really don't know.

    Maybe I'll try ABS now on some small objects, but ultimately I need to print PLA since I need to print large objects.

    Cheers, Duane.
     
  18. bluemoth

    bluemoth Member

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    I just remembered that I have to really tighten the screw to hold the heat cartridge in the heat block. When I look end on I can see light coming through in between some parts of the heat cartridge. Essentially, if north is up and west is towards the nozzle, then being clamped in the north-west and south-east positions, and there are gaps in the other positions. The gap is less than 0.5mm at the largest part. Do you think this would cause uneven heating or higher heating at the top of the heatblock and lower heating at the nozzle?

    I can try and turn it around to see if I can get better clamping or add some heat paste??

    Cheers, Duane.
     
  19. marcosfg

    marcosfg Member

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    I am also having jamming issues with the new v6. I have already filled the form, but will also share my problem here.

    First, I must tell that I am a happy v5 costumer. I have a kossel mini based printer with a v5 installed and working almost 12h a day with both PLA and ABS for 2 months. I only had 1 jam.

    I started building a new kossel mini printer and decided to go for the v6. I manage to print small parts like the double calibration square from thinguiverse. However in between prints the filament jamms. I can easily retract the filament but I can not extrude. When I pull of the filament the tip is thicker that the rest of the filament, it has around 2mm when the filament is 1.75mm.

    From what I have seen, it seems that the heat sinks gets a bit hotter then the v5 design. I have also installed a maglev fan to see if it would make any difference, but it didn't.

    Today I will try to "overkill" the cooling. I am planning on installing 2 40mm fans. 1 pushing, and the other pulling the air from the heat sink. I will then post my results.
     
  20. marcosfg

    marcosfg Member

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    Today I used 2 40mm fans to increase the air flow in the heat sink.

    I first installed the fans with an angle of 60ยบ from each other blowing air into the heat sink. At the beginning I believed that i could have solved the problem since i managed to print a coupled of layers with a consistent PLA flow without jamms. However, about one hour after it jammed.

    I then installed the fans aligned with each other. One blowing air into the heat sink and the other pulling the air from the heat sink. With this design I haven't managed to print the first layer.

    On both times I have pulled of the tube from the extruder and measured the filament diameter. The filament leaves the tube with 1.75mm of diameter. The tip of the filament is a bit thicker, 2.09mm in both.

    I uploaded some photos from one of the installs and from the filament leaving the tube after the jam.
     

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