E3D-v6 hot pulling jams - solved

Discussion in 'E3D-v6 and Lite6' started by spinorkit, Jun 29, 2014.

  1. spinorkit

    spinorkit Member

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    After over 6 months of trouble free operation of my 3mm direct E3Dv5, I was disappointed when my new 3mm direct E3Dv6 required disassembly every time I needed to change filament, i.e. even hot pulling ABS was not possible without applying extruder-breaking levels of force. With my E3Dv5, I commonly change filament mid-print (to change colour for example) using the Marlin M600 feature. Obviously there was no way I could try this with the E3Dv6.

    To investigate what was wrong with the v6, I disassembled it and examined a hot pulled ABS plug that I had removed from the heat-break after unscrewing the heatsink and applying a lot of force. I measured the plug’s diameter to be 3.3mm. I found it would fit into the bottom end of the heat-break but not the top end. It would not fit into the heatsink at all (I think the heatsink ID is 3.175mm).

    So I drilled the heatsink out to 3.3mm (carefully, using cutting oil) so the plug would pass through. I then screwed the heat-break into the heater-block and tightened the nozzle in the normal fashion (gripping the heater-block). I put the heater-block in a vice and attached a fine round file to my drill and carefully, using counter-clockwise rotation so the file did not try to self-tap its way in, enlarged the ID of the top of the heat-break until the ABS plug would just slide in.
    I then washed everything out with detergent and high pressure water.

    The v6 now hot and warm pulls both ABS and PLA without problems, just like my v5.

    I have a theory on a possible cause of this v6 problem. I think it possible that the polishing of the lower part of the heat-break slightly increases the ID of the lower part. If the ID of the hotend ever decreases on the way up from the bottom, especially above the melt zone, this sort of jamming is going to occur. I suspect that it could also increase the likelihood of jamming while printing if retraction is set to a large value, such as the default of 4.5 mm in Cura, which may be appropriate for Bowden systems, but is way too much for non-Bowden.

    My suggestion is that the internal heat-break polishing should start from the top of the heat-break, not the bottom, since in the melt zone the surface roughness does not matter; it only matters in the transition zone. In addition, I suggest the heat sink ID should always be larger than the ID at the top of the heat-break.

    I do love my E3D hotends, especially the v6 now it’s working well :) .
    Kind regards,
    Kit
     
  2. pf26

    pf26 New Member

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    Hi,
    Thks a lot for sharing. It makes sense to me that inner polishing should be done from top (filament entrance) and that the inner diameter should only (slightly) decrease from there to hot section - Otherwise retracts will cause issues.
    I like the design, and I was about to buy some E3D-V6, when I found several posts about jamming...
    Now I would really like to read from E3D regarding inner diameter profile.
    Thks in advance..
    Pierre
     
  3. krap

    krap New Member

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    Hi,
    I'm agree with pf26.
    I had a lot of jamming issues with my v5, so I'm really looking forward for an answer before buy a new v6.

    I will certainly buy the complete v6 + an extra heatbreak that I will try to polish all its inner surface...
     
  4. bryanandaimee

    bryanandaimee Member

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    I have the same issue. The heat break and heat sink really need to be machined so the hole is uniform throughout or slightly widening towards the top. It's impossible to get the filament out unless it's very warm. I guess I'll be buying some drill bits.
     
  5. spinorkit

    spinorkit Member

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    Another option might be to order a v5 heat break and just replace the v6 heat break with that. I have not tried this yet, but if E3D don't indicate they have fixed this problem with the v6 heat break before I order another v6 hot end, I will do so. I really hope they have changed their manufacturing process with regard to this.
     
  6. elmoret

    elmoret Administrator

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    1.75mm heat breaks are not cross compatible, different external thread sizes.
     

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