Jamming

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

  1. bluemoth

    bluemoth Member

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    I will keep trying.

    I have three primary potential causes:
    1. the extruder
    2. the filament, though I've tried many from different sources and filament sizes and colors.
    3. the hotend

    I have a Bulldog XL extruder and Merlin hotend arriving tomorrow (I hope). So I should be able to eliminate or identify the extruder or hotend as the potential cause. I will change one thing at a time, starting with the extruder, then the hotend.

    Cheers, Duane.
     
  2. bluemoth

    bluemoth Member

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    Hi Josh,

    Have you got a formalised testing procedure. It'll be great if you had a process. I didn't try ABS because I need to print my big jobs in PLA.

    My last failure turned into a birds nest.

    Cheers, Duane.
     
  3. spinorkit

    spinorkit Member

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    First up, I need to say that I have no experience with Bowden systems, since my printer is a Prusa i3 with the extruder mounted to the x carriage. I do know that driving filament (again I have only used 3mm filament) takes a lot of force, especially for PLA at temperatures below 200C. Lack of grip of the hobbed pulley on the filament is a potential source of problems especially with PLA, and this causes the "deep scar" you mention.

    I use 2 types of geared extruder, a Wades and a modified Prusa Compact.
    I would not be happy using an extruder like the one in the documentation you linked to:
    1. That is not a hobbed pulley with a concave hobbed groove which means the area of filament being gripped is small resulting in increased likelihood of slippage due to the PLA fracturing where the teeth contact it.
    2. It seems to use PLA structural springiness instead of proper idler tension springs, making the idler tension sensitive to things like filament diameter and hardness.
    3. No gearing. The way I determine both the temperature and the idler tension to use with a filament is by turning the large gear (connected to the hobbed bolt/pulley ) by hand and extruding into free air. I increase the temperature until only a reasonable amount of force is needed for extrusion (by now I know what it should feel like) and I increase the idler tension if I feel any slippage. I also put marks around the idler pulley using a felt pen so I can visual detect any signs of slippage.

    I think you should increase the filament idler tension until the filament shows signs of deforming and has deep grooves.

    Bear in mind it is quite possible the thermistors in your v6 and your other extruder might be giving quite different temperature readings. So the other hotend might have actually been running at a higher temperature.

    Keep the retraction distance below 3 mm and retraction speed below 25mm/s to start with, and only increase these when you have reliable prints.

    Have you calibrated your extruder steps per mm?

    Cheers,
    Kit
     
  4. ThibautInpg

    ThibautInpg Member

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    Hello everyone,

    I discovered this forum thanks to a friend of mine, and I'm convinced that I'll find some very useful advice in this topic.

    I have worked with some other students in my engineering school on a huge version of a Rostock in the past months, and we had a lot to do.

    In the end, we had some jamming issues, and I'm currently going back to working on these issues, so I'll gather the informations about what is our configuration, what we did and what are my current problems.
    By the way, I'm not sure if we do use a customized E3D v6 or a homemade HotEnd, but when I read this topic I'm convinced that we have common issues and solutions.

    Here is the rpinter itself, with a bowden:


    Here is a zoom on the central part:


    The hand was not bad, but we didn't manage to have a lot of good results.
    You can see an additional cooler, and the cooling nozzle was printed with this printer. We had some issues with the heat diffusion in the upper part of the hotend.

    I'll update this post by the end of the afternoon, or by tomorrow.

    In advance, all apologies if I make some english mistakes, it's not my natural langage. ^^

    Cheers,
    Thib

    PS: By the way, how can I resize attachments?
     

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  5. jesse

    jesse Member

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    I noticed that two of my v6 nozzles vary in length by about 0.25 mm. If you get jams after switching nozzles, the steel liner may not be firmly connected to the nozzle. To fix the problem, rebuild the hot end and use the shortest nozzle...
     
  6. Josh

    Josh Administrator
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    Firstly all, sorry about the delay in response, we have had a lot on here at E3D over the last couple of weeks…

    Questionnaire: https://docs.google.com/a/e3d-online.co ... =send_form

    Kals,
    Based on your responses in our questionnaire, it seems that the problem is not actually with your cooling. You seem to be using the wrong thermistor setting in Marlin - to confirm this should be 5, not 1. This is probably causing your issues.

    Also 45mm of retraction is enormous, I assume you meant 4.5mm which is still quite large, on a direct you should not need to go over 3mm. If after fixing your thermistor values you are still having troubles, start at 0mm and work up slowly (0.5mm at a time).


    McHampoux,
    Sorry to hear your extruder arm is broken - nightmare!

    In the mean time I have had a look at your responses to the questionnaire, and a few things stood out to me.

    1. 870mm of Bowden tubing is quite long, is there any way you can reduce this a bit?
    2. Fan controlled by software - just rig this straight up to 12v. It should be on the whole time.
    3. Thermistor #1, as I said to Kals, this needs to be 5 or you will not be getting accurate temperature readings.
    4. 10mm retraction @ 30mm/s, try reducing this down to say 2/3mm and see how you get on. Also you can probably get away with upping the speed to 40-50mm/s.


    PLAgoaway,
    You are quite right, you should not have to make modifications to your HotEnd to get it up and running - in the overwhelming number of cases, the E3D-v5 and v6 are very much plug & play, and given that this is not the experience you are having there is clearly something wrong.

    Can you please fill out our questionnaire so that I can try and establish what the cause of your problem is - if it looks like it could be our fault, we will just exchange your HotEnd without question. As everyone knows, we will always stand by our product.



    Bluemoth,
    How did you get on with the Bulldog XL extruder? Did you test the Merlin?

    We don’t have a formalised testing procedure, though it is something we are looking at. The issue here is there are so many possible causes for problems that a one-size-fits-all testing regime is not really a possibility. Our questionnaire is an attempt at reliably collecting data on causes for failure and in most cases it catches something which is relatively easy to rectify.


    Jesse,
    Are you still having problems? If so, can you fill out the questionnaire and I can try and help you out.


    ThibauInpg,
    What problems exactly are you experiencing? Can you fill out our form and we will look into what may be the cause.


    Cheers for your patience guys.
    Rest assured that we will get everyone up and running.

    Thanks,
    Josh
     
  7. bluemoth

    bluemoth Member

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    Hi Josh,

    Thanks for the reply. I got he bull dog but it meant probably half a day printing modifications to install it, so I decided the install the Merlin hotend instead. I had it on the printers ready to print, I only had to adjust the bed height then decided I was too close to a complete print to give up in the E3D-v6 so I put it back on.

    In the end I gave up trying to eliminate one thing at a time and change 4 things.
    1. Changed may print fan ducts to reduce the air going on to the print head.
    2. Added crinkled up kapton tape around the heater block to add insulation.
    3. Started wiping olive oil on the filament.
    4. extended the PTFE tube to be closer to the hobbed bolt.

    I think all improved the situation, but I suspect it was the last two. I found the 1.75mm filament was riding up off the hobbed region on to the smooth part of the bolt. Most times the filament would pop off back on to the hobbed region and keep feeding. This is due to the pressure driving the filament into the hotend. Extending the PTFE tube made it harder for the filament to ride up onto the smooth section of bolt, but I think the oil made the most difference.

    The oil made it harder to rider up on to the smooth section of the bolt and easier to slip off. Also it lubricated the inner of the hotend which reduced the pressure. Why do I say this? because my stringing has reduced massively. Correct me if I'm wrong, but I suspect my stringing was from pressure. When the nozzle moves off one structure, into mid air, to another structure, suddenly the pressure reduces which allows the pressurized filament in the hotend to escape creating a string, usually with a glob. Now it pretty much gone. I cannot see why improvements 1,2, and 3 could do this.

    So things are working good so far. I've learnt not to get my hopes up. I've only had one 12 hour print succeed. In the future, it'll be cool to find ways to reduce PLA pressure.

    For the meantime i'm going to keep going with this setup until I get my printing jobs done.

    Cheers, Duane.
     
  8. ThibautInpg

    ThibautInpg Member

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    Hi Josh,

    I filled the form, but I don't want to get you wrong:
    The printer I'm working on is from a former project, and I think that many of the hardware is "homemade" (in a lab though, but still...).
    They wanted to use what they had so they made the hotend with an EBM machine, which looks pretty cool but has terrible results on the smoothness of the pieces. Plus, the nozzle and the push fit connector threading aren't clean.

    All that resulted in many problems linked to thermal conduction and pressure in the hotend. That's why I posted here, because I saw that although we have different hardware, the problems are similar.

    Eventually, I disassemble the hotend and here is what it looks like. I Think the two main problems are lubrication and the cooling. I'll work on that to see what I can do without changing the design or getting a new hotend, and this will help maybe some people here ;)

    Cheers, Thib

    [​IMG][​IMG][​IMG]
     
  9. GlitchE

    GlitchE Member

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  10. PLAgoaway

    PLAgoaway Member

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    I submitted the questionnaire 3-4 days ago. When can I expect to hear from you? I also e-mailed you guys some time ago, but havn't received a reply from that either.
     
  11. kals

    kals Member

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    Josh, thank you so much for your suggestions! Changing the thermistor setting did the trick. The first print after doing this came out beautifully, a great improvement over the print quality of the original printhead that came with the printer! My retraction was 4.5 as you assumed, I have taken it down to 2.5 now.
     
  12. Josh

    Josh Administrator
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    PLAgoaway,

    Thanks for sending your HotEnd back to us, we received it in the post this morning and I have done some tests on it to try and figure out what was wrong.

    The first thing I noticed when taking a look at the HotEnd was that the Fibreglass Insulation looked very blackened, more than I have seen before on any of our printers, which print everything from PLA to PC. Taking a closer look I also saw what looked like PLA streaks where very hot PLA with a low viscosity had been flowing around on the surface of the Heater Block.




    These signs coupled with the fact that you have been experiencing jamming pointed to inaccurate thermistor readings so I checked that our for you, and it's giving you accurate readings - so no problems there.

    The HotEnd was then disassembled and the nozzle orifice length checked - that came in at 0.6mm which is correct.

    To check the HeatBreak, I milled it in half to have a look inside, this is what I saw:





    It seems that PLA has cooked inside the HeatBreak. In the second photograph I have scratched away the PLA and we can see some yellow staining in the HotSide which suggests that the HotEnd has been quite hot at some point with PLA inside it.


    At this point I would like to blame the HeatBreak, there was either contamination present when it was shipped to you originally or it has gotten to a temperature where the PLA has broken down and this has negatively impacted the surface of the break thus causing you jams.


    To get this issue resolved, I am going to post your HotEnd back to you tomorrow with a replacement HeatBreak (and nozzle - you had done a good job of stripping the Hex-Head off the one you sent us! :p).

    For your first print, can you print the Make Torture Test (http://www.thingiverse.com/thing:33902) in your Black ColorFabb PLA using the following settings:

    Temp: 215
    Retract: 0.5mm
    Retract Speed: 40mm/s
    Print Speed 50mm/s
    Layer Height: 0.25
    Nozzle: 0.4mm
    With the fan mounted in the middle of the HeatSink running continuously.


    Let us know how you get on with this first print.

    Cheers,
    Josh
     

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  13. grat

    grat Member

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    At the risk of side-tracking the thread... Bravo.

    THAT is customer support. :)
     
  14. Eaglezsoar

    Eaglezsoar Administrator

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    The staff at E3D has always had excellent customer support.
    Some need to contact the staff at E3D instead of just complaining.
     
  15. Marwijn

    Marwijn Member

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    Hello Josh,

    Looking at this picture I wondered why there seems to be a jump at the positions marked with the red circle. To me it almost seem that there is a discontinuity where the heatbreak is. If so that combined with a bit rough filament (by the extruder) could possibly cause some jamming.

    Kind regards,
    Marwijn.
     

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  16. Sanjay

    Sanjay Administrator
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    Those are just thin burrs from when the part was milled in two, the bore in those sections is completely contiguous. I'd also like to point out that a lot of the scratches you see inside the bore were made after machining in two by scraping off the mystery black stuff adhered to the walls with a hardened point engineering scribe, that's not how the bores appear in their shipped state.
     
  17. tailgunner30uk

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    "To get this issue resolved, I am going to post your Hot-End back to you tomorrow with a replacement Heat-break (and nozzle - you had done a good job of stripping the Hex-Head off the one you sent us! :p). "

    Wow, that is one seriously abused nozzle.

    Might I suggest that investing in a set of metric nut drivers might well reduce the damage inflicted here.

    Also, I noted that the nozzle seems to have been tightened against the heat block. This may have resulted in problems at the interface of the nozzle to the heat break.

    As an aside, might it be worth considering a change in the next revision, to using the Kraken heat break secured by grub screws. This might also add the facility to quickly change heat-blocks, pre-assembled with nozzles for filament changes and nozzle changes.

    Just a thought.
     
  18. Fmeroney

    Fmeroney Member

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    ****This is a repost from another post f mine****

    Had the same issue, it seems my filament was kinking and sticking to the wall therefore causing the print to fail. So what i did was put the PTFE liner (one in the bag of parts that i had no idea what to do with... Even after youtube vids) in the hotend with the black coupler. I trimmed the tube flush with the black insert and Its working great. If this was the intention from E3D it would have been nice to know... Like the design but thats a simple issue.
     
  19. mchampoux

    mchampoux Member

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    Hi Josh,

    Sorry for the delay in my response, I didn't have much free time lately. So, I was able to re-hook up the E3D-v6 hotend to my Kossel Clear and re-try today... and I have bad news... it jammed right away on the 1st layer...

    - I followed your suggestion of shortening my bowen tube from 870mm to 670mm... that's as short as I can make it.
    - I hooked up the fan so that it would be on as soon as the printer had power.
    - Before trying to print, I updated the termistor value from 1 to 5 in the marlin firmware and re-uploaded it to the arduino.
    - I re-sliced an object I had previously printed correctly with the hot-end that comes with my Kossel clear with the retraction down to 2mm at 40mm.

    And I still got a jam... this is really strange...

    Do you have any other suggestions at this point?

    Thank you,

    Marc
     
  20. grat

    grat Member

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    As another KC owner, I'll ask if you have the BEL acrylic extruder, or the community preferred Shane's ArmDrive?

    The acrylic one works, but it's tempermental, and Shane's is much easier to work with.

    The other change I made was to reduce the microstepping to 1/8th (instead of 1/16th) on my extruder-- obviously this means cutting the steps/mm in half in the firmware configuration.

    I'm currently using 1.5mm retract with a speed of 60mm/sec.

    Finally, did you recalibrate your PID settings? The new head / heater / thermistor is completely different to the stock J-Head.
     

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