Jamming

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

  1. elmoret

    elmoret Administrator

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    Yes, it should be hardwired to 12v.

    Have you taken E3D's questionnaire?
     
  2. kals

    kals Member

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    Here is some images of my setup: https://www.icloud.com/photostream/#A453qWtHGBPszb

    My fan is connected in parallel to another fan cooling the board. Could this decrease the performance of the fan? The fan seems to be pushing a lot of air, so I would think it strange if a small increase in the fan-speed should be able to resolve the issue..
     
  3. Ralph Hilton

    Ralph Hilton Well-Known Member

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    Having the fans in parallel is not good. The bed cooling fan needs to be off for the first layer. It also looks to me as if the bed cooling fan is blowing onto the hotend. It will force the heater to work harder causing more heating of the heat break. I use a ducted bed fan separately switched as at http://www.thingiverse.com/thing:371252 .
     
  4. kals

    kals Member

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    I do not have the e3d fan in parallel with the cooling fan on the printhead, but the cooling-fan of the motherboard beneath the printer, so it does stay on permanently..
     
  5. jesse

    jesse Member

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    I think the problem with jamming is related to retraction. The plastic is melted and gets pulled into the cool section. Then the plastic hardens inside the steel liner and gets stuck.
     
  6. mchampoux

    mchampoux Member

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    Hi Jesse,

    Retraction? That's a good idea to try: I will lower my retraction settings to see if I can get to print something tonight.

    Btw, I tried to print again last evening... no luck... 5th jam.

    Marc
     
  7. mchampoux

    mchampoux Member

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    Well, quick update to say that I'm dead in the water even before I could try to print!

    This time it's because a plastic part on my extruder broke: the super important part of the "arm" that presses the filament against the small wheel with grooves on it that pushes it into the tube.

    I could try to McGyver something but I think it's safer for me to wait for Blue Eagle Labs to send me a replacement part.

    Now I'll have to wait a week or two before I receive the replacement... just my luck...

    Marc
     
  8. marcosfg

    marcosfg Member

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    Hello,

    I believe I have managed to resolve my problems with the hot end jamming. I have managed to print a 5h skull and I am successfully printing both PLA and ABS for 2 days without any jamm.

    Since I had a v5 fully working I was started wondering if the smaller heatsink from the v6 could be a problem. However, I also noticed that the fan in my v5 seemed to blow more air than my v6 fan. I have decided to buy some extra parts from the e3d shop: a v5 heatsink, a v5 heartbreak and a fan.

    This week I have received the parts. I decided to start with the simplest modification... replacing the fan. And it WORKED! I haven't even tried to exchange the heatsink.

    I have noticed that the new fan I have received has 5 fins and is much quieter than the first one.

    Apart from the fan replacement there were also some other changes I have made:

    - I use a 2mm retraction, when I used a 8.4mm retraction on the v5.
    - I used to retract 100mm when the printer would be switched off. I read somewhere that it was a good practice to pull the filament off the hot end after completing the prints. I have noticed that this was causing the hot end to jamm after a printer restart.

    I will continue to test the hot end in the next few days and will post anything else that I find that can help.
     

    Attached Files:

  9. marcosfg

    marcosfg Member

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    P.S. I now have an extra v5 heatsink and heatbreak... anyone needing one of these???
     
  10. bluemoth

    bluemoth Member

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    Hi Marcosfg, What size fan did you replace it with? Cheers.
     
  11. marcosfg

    marcosfg Member

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    I have replaced it by the standard 30x30 fan. Apparently the first one that came did not blow enough air...
     
  12. bluemoth

    bluemoth Member

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    Sorry for the long story.

    I am at a wits end. I've nearly tried everything. I got close with 3mm hotend with a direct wade extruder but it was still unreliable.

    1. Replace the 3mm hotend with the 1.75mm hotend. It seemed great at first but then it started jamming after a few layers. The PID parameters were Kp=23, Ki=2.2, Kd=61. Started a print that failed after 3-4 hours.

    2. I disassembled and reassembled the entire hotend including the heater block. I used heat paste with the heater cartridge and thermistor. I get PID values of Kp=40, Ki=6.6, Kd= 61. So clearly something made a difference.

    Print 1 (@195C) fails after a few layers. I was using the wrong old PID settings.
    Print 2 (@195C) fails after 7 hours!!.
    Print 3 (@205C) succeeds after 20 hours. Yay.
    Print 4 (@205C) fails after 3 hours.
    Print 5 (@205C) fails after 6 hours. Print moving around on bed. Not sure if print disassociated or a jam occurred, then printed a birds nest that pulled it off.

    3. I decide to build a Bowden extruder because of reports that this jamming is only with direct drives. Printing parts for the mod show signs of jamming but manual intervention recovers the situation except 1 print.

    4. Built a Bowden extruder. The first filament I tried was too thick. I swapped a new filament in that is smooth to push through the tube. Prints fail after a few layers. I stop the print, test the filament in the tube and it's still smooth. The jam is in the hotend.
    Print 1 @205C fails after 1-2 hours.
    Print 2 @215C fails after 1-2 layers.
    Print 3 @215C fails after 1 layer. It seems to fail (in print 2 and 3) during the print of the support. The brim looks perfect.
    I cannot get the filament out of the hotend nozzle. The extruder clicks when it starts to fail. The motor is not skipping but the filament is popping on the hobbed nut. Clearly form the pressure, not from the tube, but from the jam.

    Other mods: I've rebuilt my z-axis with brass nuts and oiled, etc... It's very smooth so I doubt it's causing the jamming. You can see I'm getting desperate.

    I have decided to go back to the 1.75mm direct drive extruder since it's given me the best results. I will modify the extruder to have the PTFE tube go all the way up to the hobbed bolt. I've been reluctant to make irreversible changes so far.

    I saw a small gap (<1mm) between the fan and ducting on one corner. I've fixed this. (I've very desperate)

    So I've eliminated most possible causes except Marlin firmware settings, the heater block, heater and thermistor, slicing software and the extruder. I've tried many sources of filament but it's still a concern. I have more on order from two different sources.

    I've ordered a Bulldog XL extruder to eliminate the Wade extruder as the cause. Also ordered a Merlin 1.75 mm hotend to eliminate the heater block as the source. I'm considering buying the Simplify3D software to eliminate Cura slicing as the source.

    I'm considering going on IRC to check the marlin settings. I bought my Prusa-Mendel i3 of a guy named Bill (norcal-reprap) on eBay. It came with Sprinter settings but the build height was limited to 100mm in the firmware, instead of the 200mm which the printer could do. I contacted Bill but he had since passed away (aged 41). So I flashed Marlin and configured it myself. I got nice prints out and printed a 24hr print. Some failed but not as often as with the E3D-v6. Unfortunately, I overheated my j-head and later broke it. So I bought the latest E3D-v6 after reading about the v5. And now, here I am.

    I have 9 of these 20-24 hour print to finish in 17 days. So you can understand desperation.

    Cheers, Duane (bluemoth)
     
  13. bluemoth

    bluemoth Member

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    Now it's 3pm so I'm going to have a beer. That should make me feel a bit better.
     
  14. bluemoth

    bluemoth Member

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    Also I get excessing stringing. I'm not sure if this is a symptom of the underlying problem. My retraction is at 0.2mm. I've tried 0.5mm, 1mm and 2mm and it doesn't seem to make a difference.

    Cheers, Duane (bluemoth)
     
  15. bluemoth

    bluemoth Member

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    I have modified the printer to have the 1.75mm hotend with a direct extruder and the PTFE tube going right up to the hobbed bolt.

    Tried a print and after 2 hours it failed. There were 2-3 partial layers before the completely missing layers.

    There seems to be significant oozing and stringing which suggests there is a lot of pressure in the hotend. I wonder if this pressure is higher than normal and whether this is causing filament to be pushed up the heat-break, cooling and creating a plug.
     

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  16. PLAgoaway

    PLAgoaway Member

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    I've spend 4 weeks, well over +120 hours in to the V6. I have yet to complete one single successful print. I've tried the following to resolve the issue. The results are explained further down, but none of them have successfully resolved the issue:

    1) Drilling out the nozzle. The bore length was 2mm. I reduced this to 0.5mm.
    2) Made sure the PTFE tubing was pushed all the way through.
    3) Placed the fan such that the heatbreak part between the cooling area and heating area got air sufficient airflow to prevent PLA expanding and thereby jamming.
    4) Reduced retraction to 0mm, increased every print.
    5) Checked diamater of filament frequently.
    6) Tried printing a fan duct that would cool the heatbreak area that caused the jam(see solution 3).
    7) Increasing temperature +5C every time a jam midprint would occour.

    Just to make it clear, none of these "solutions" worked. Drilling out the nozzle helped a little bit, it basically confirmed that the hotend was the issue and not the extruder or something else. Making sure the PTFE tubing was inserted was just a matter of checking, and yes, it was pushed all the way down. Placing the fan further down towards the heatbreak also helped a tiny bit, but jams still occour frequently. Reducing retraction didn't help noticeably, just made prints uglier. Diameter of the black PLA from Colorfabb checked out. Was unable to print fan duct, since, you know, it doesn't work :lol:. Increasing the temperature only helped for a couple of layers before another jam occurred. This is the technical part, if you're not interested in my personal opinion, stop reading :)

    I know the general idea is to try and find a solution by trying different methods, fan ducts, seasoning, drilling etc. but just to make it clear. Why do I have to try these methods when I payed a sufficient amount of money to avoid all of these problems? I know the hotend isn't exactly plug and play, but seriously, seasoning? No. Printing a fan duct because of faulty design? No. Drilling out the nozzle because you didn't manage to get the dimensions right? No. I really do think it's great that we are all trying really hard to resolve these issues, and as a someone who loves spending many hours tinkering with these things it is absolutely amazing. But as a customer this is absolutely unacceptable :(. I'm at a point where I don't know what to do, so I'll just sit here, and wait. I can provide pictures of the whole thing if that helps.
     
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  17. spinorkit

    spinorkit Member

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    After trying so many things, I would look at things other than the hotend.
    What sort of extruder are you using, is it geared?
    How hefty are the springs on the extruder idler?
    What sort of hobbed bolt/pulley?
    Extruder temperature staying constant during long prints?
    Have you tried printing ABS?

    Cheers,
    Kit
     
  18. PLAgoaway

    PLAgoaway Member

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    I'm using the Nema17 extruder setup from this guide (see page. 112, section. D31 for start of extruder-assembly) http://blomker.com/Kossel_Mini_Assembly_Guide_V1.0.pdf. The whole kossel mini set came with a stock hotend http://blomker.com/index.php?id_product=28&controller=product which worked perfectly for some time, until it started leaking. A friend of mine told me about the V6 and ordered one for me and one for himself. He hasn't had any problems. I only have problems.
    I don't believe this is a extruder problem since it has been working with another hotend. Is this assumption wrong? To be honest I just want to send them the whole thing back, I'm wasting time trying to fix this.

    Just a little more info on the setup:
    1) I'm using direct-drive. I have the bowden coupler but have not used it, since direct-drive should do it yeah?
    2) The drive gear attached to the extruder-stepper-motor leaves little marks on the filament as it passes, but nothing serious. I think.
    3) If I try to push the PLA jam out by repeatedly extruding, the filament will have a deep "scar"(?) which ends in the extruder not being able to grip the PLA after some time. Does this indicate anything wrong?

    So as you can see there are probably a few other things I could try out, but as I mentioned in the beginning, it worked with a stock hotend, probably worth 20-30$ (10-18£), so why isn't it working with a "quality" hotend at +40£.
     
  19. jesse

    jesse Member

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    I found a possible solution for v6 jamming for printing PLA at 200C.

    The steel liner was glued in place using blue permatex thread locker on both the heat sink and heater block.

    The nozzle was unscrewed about 1/4 turn during re-assembly. That way, the steel liner comes in direct contact with the nozzle when the nozzle is tightened.

    If the nozzle is not directly pressed against the steel liner, PLA can escape into the gap and cause a jam.
     
  20. bluemoth

    bluemoth Member

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    Last night I decided screw this and increased the temperature to 235C for my PLA print. The print looked great, there were a little less strings and it was a little glossy. Then 11-12 hours later, it jams and skips a couple of layers, then frees up again. This could be an extruder problem but after 11 hours??

    Is 235C for PLA normal? Is my thermistor reporting the wrong temperature?
     

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