**SOLVED** Constant jamming - v6

Discussion in 'E3D-v6 and Lite6' started by Markmcc, Aug 1, 2016.

  1. Markmcc

    Markmcc Member

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    So, to paint the scene - I've gone back approx. 20 pages in the forum and read every post on jams and actioned many of the recommendations.

    I've had approximately 400+ hours of problem free use. So I'm confident feed rates, temps etc are bang on perfect.

    I had a rare gcode error (computer crashed) that saw the print head plunge into a job and broke the heat break.

    I ordered replacements on ebay (which i think is the problem) as I couldn't find a single site that sold them individually.

    I've disassembled and reassembled 15x now chasing the problem. (Using Tom's guide on youtube).

    Have replaced the ptfe tube.
    Have replaced the nozzle. 0.4mm (did this with 3 new nozzles)
    Have replaced the head break. (did this with 3 different ones, all new)
    Have used thermal paste.
    Have turned off retraction.

    Using PLA (previously used spool with no issues).
    Heated to 205.
    Prime the print head with 30mm extrusion with no problems.
    Then between that and starting the print (5-10 seconds) it seems to develop heat creep and produce the blockages at the base of the ptfe tube back up the heat break. (No retraction).

    Have tried 4 other spools - all new and fresh out of their shipping bags.

    I'm not sure what else to try. Short of changing to a different hot end.

    Pics attached of the hot end.

    20160801_211519.jpg 20160801_211420.jpg 20160801_211312.jpg 20160801_211235.jpg 20160801_211123.jpg 20160801_210737.jpg 20160801_205536.jpg
     
    #1 Markmcc, Aug 1, 2016
    Last edited: Aug 1, 2016
  2. elmoret

    elmoret Administrator

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    #2 elmoret, Aug 1, 2016
    Last edited: Aug 1, 2016
  3. mike01hu

    mike01hu Well-Known Member

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    Those pictures seem to indicate a space between the bottom of the PTFE tube and the bottom of the recess in the heat break. This will cause the melt from the heater block to migrate upwards to accumulate in the gap, solidify and cause a jam. It does not necessarily need retraction to draw the melt up into the space, as normal feed pressure will do this too. It is very important to ensure that the PTFE tube is cut off square and is secured properly with the Bowden clamp so it cannot move up and down in the hotend.
     
  4. Markmcc

    Markmcc Member

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    Interestingly, this is a wades setup and I can't fit the bowden clamp into the end of the hotend and get it into the extruder assembly. I don't disagree with your observation but am perplexed as this exact setup hasn't been an issue for 400+ printing hours. The PTFE tube runs up the entire extruder assembly and is cut flush with the hobbed bolt. The other end of the PTFE is definitely cut sqaure (I have a jig to ensure that).

    I'm wondering if the heat break has a slight taper on the inside (tapering down like a drill bit tip) that is preventing the PTFE sitting flush. It could be that the manufacturer used a stepped drill bit instead of an end mill.
     
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  5. Markmcc

    Markmcc Member

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  6. elmoret

    elmoret Administrator

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    Might be worth an email to them, they might have it and just not have it listed on the site.
     
  7. asmeets

    asmeets Member

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    I have a Monoprice i3 v2 that I had to change the extruder motor on. Since then, I have been having quite the time trying to get it to print properly. I have been doing all my testing with Maker PLA. I was using Benchy as my test, every single time it failed halfway through, acting the same way as you are describing. Currently I am printing a 20mm^3 test cube with 20% infill.

    -Alex

    [​IMG]
     
  8. asmeets

    asmeets Member

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    UPDATE:

    I know I just posted my problem on here, but I was able to get a perfect looking cube. I have many different retraction distances and finally found my golden retraction of 0.6mm. I am going to assume you already tried that yourself, but if you haven't, I would.

    -Alex
     
  9. mike01hu

    mike01hu Well-Known Member

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    Your analysis is most likely correct and I go with @elmoret in that you should obtain the genuine part.
     
  10. Markmcc

    Markmcc Member

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    **an unconventional solution has been found**
    I received a message from a kind forum person who suggested fan/shroud orientation.

    So tonight I did two things (well a few more but you'll see in a minute).

    1. inverted the fan and blue shroud so the cutaway is facing down.
    2. reamed the PTFE tube.

    #2. I can hear some of you saying WTF?
    I took a wax casting of the interior of the heatbreak to confirm the internal end had a taper as suspected. So I reamed the end of the PTFE tube in the hope it would sit flush/further into this taper. It does and I'm now conservatively printing at 60mm/s and everything is back on point again.

    This should get me by until I can track down a lazy Australian supplier with an authentic heatbreak.
    It also now gives me great grounds to leave feedback for the ebay seller, warning others of the shortcoming of the product.

    Thanks again to all who took the time to read and reply. Sometimes just talking things through can point to other areas to investigate.

    Rock on fellow printers.
     
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  11. Markmcc

    Markmcc Member

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    Got the parts en route. :)
     
  12. Montague Flange

    Montague Flange Active Member

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    I used the little bowden locking clip on the top of the heat exchanger to hold the PTFE tube in and stop it moving during retraction. . I'm also thinking of using the bowden feed inset instead of the longer PTFE as the heat doesn't get that far anyway and would be no different to a bowden set up for that. but it might make loading a bit easier.
     

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