Jamming with 3mm E3D V6

Discussion in 'E3D-v6 and Lite6' started by Lon, Oct 18, 2017.

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  1. Lon

    Lon Member

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    Bought V6 Direct kit to replace the old heater on my Mendel printer with 3 mm filament. Keep having jams of filament (ABS or PLA) that will not pull back or push out nozzle. I can heat to 200C, remove nozzle, and then tap the filament down into the heater block. If I heat the stainless steel with the block inside, the 3mm filament has a 3.5mm diameter blob on the end that would have been at the heat block zone.

    The kit does not have teflon tube and did not include any heatsink paste (it is probably 1 year old production). Heat block zone is definitely larger than the ID bore into the heater. Bore at the top of stainless rod is also slightly smaller, which is perhaps why I can't just pull the filament back into my (geared NEMA-17) extruder.

    It will start and print, first time, but once the print ends and the head cools, I have to do the hot nozzle 'remove and purge' and pull the filament out, before I can start another print.

    I expected the stainless rod would have constant diameter bore. Suggestions, please!
     
  2. Old_Tafr

    Old_Tafr Well-Known Member

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    I assume there are three parts to the 3mm (I have 1.75 mm setup with ptfe tube)

    A. The heat-sink (finned bit)

    B. The heater block (the bit the heater and thermistor & nozzle are mounted in )

    C. The "heat break" threaded tube (your "stainless steel? or your "heat block" ? ) joining A to B

    I suspect that the fact that a print works is that the filament is in constant motion (so keeping the heat and molten filament flowing away from the heat break {where the blob occurs?}) but that once the printing stops heat soaks back up through the heat break into the heat sink and the filament is soft and forms a blob in the heat break.

    Could this be due to...

    D. Lack of heat sink paste? (better to buy a small syringe as used for decades in electronics rather than the silly "one use" sachets)
    (paste is only applied to the heat break/heat sink joint not to the heat break/heat block joint.)

    E. Fan not directed onto the heat sink properly (uses a {blue?} shroud like the V6 on the BigBox?) or fan not big/fast enough
    (shroud is not symmetrical supposedly not making any difference but the cutout needs to be at the bottom)

    F. Fan does not stay on long enough (on the BigBox Rumba the fan comes on/goes off at 40oC )

    ---------------------------------------------------------------------------------------

    Whilst looking for the solution to my problems with Edge I came across this...

    Extruding Temperature
    Too hot
    Too cold

    Clogged Extruder

    Found here...

    http://reprap.org/wiki/Print_Troubleshooting_Pictorial_Guide

    Which may have some clues to your problem.
     
    #2 Old_Tafr, Oct 19, 2017
    Last edited: Oct 19, 2017
  3. Lon

    Lon Member

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    Thanks for feedback. Have ordered a replacement heat break, since that is the heart of each potential cause. Have blue molded plastic fan shroud and fan blows across heat sink any time power is on printer (for now). Used 20 year old tube of white heatsink compound, but it lasts a long time.
    Found I can pop the fan and warm the bottom of heat sink to release jammed filament, instead of disassembly.
    Have found adding 12 mm retract cycle at end of Gcode seems to help, at least with PLA.
     

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