Hotend woes and heater faults



  • So, I tried out a cheap knockoff of the E3D Cyclops. it is best described with one word. "Jams" Thats all it did, so I guess I have to save my pennies for a real Cyclops. Unless you the community can tell me if there is a better way to get dual material / dual color printing?

    Also, Once I put my E3d v6 back until the dual do-over, I am now getting heater faults. The hotend temp will suddenly run crazy and the system will halt due to the fault. Hooray for safety cutoffs!

    What could cause this? it was working fine before. I have not reconfigured anything. I did a autotune and tried again and it did not help. However, during the autotune the Duet reported that my hotend was overpowered and might run up to 600 something degrees. That was new.

    Any idea what is goin on?

    background info: This is a Duet Wifi board verson 1.02, Running firmware v2.02
    The printer is a Cartesian style, (see the AMV8 design on thingiverse) and the hotend is an E3D v6 all metal.
    I have two bondtech extruders on the top rail, headed for dual bowden style setup.

    I get about onto the 3rd layer or the 4th layer and it halts in the same place each time...... weird.



  • @jkaechler Probably 2 or 3 different things going on.

    The problem with the clone printing OK for a few layers then stopping due to a jam is a classic sign of heat creep. Whereby the plastic softens and swells in the area of the heat break. It might just be a bad design but to too much retraction can cause molten or semi molten plastic to get drawn up into the heat break area where it will cool and solidify. So lower retraction might help, as might printing at a lower temperature and /or improving the air flow over te heat sink if that is possible.

    Ref the heater woes. The fact that the heater can be OK but then "suddenly run crazy" is usually a sign of a wiring fault such as a bad crimp.

    Do you by any chance have a silicone sock on the V6? This can sometimes lead to the over powered heater warning. What it means is that if a Mosfet failed in such a way as to leave the heater fully on with no control, then it could potentialy reach 600 deg C. So don't leave the printer unattended but longer term, you should seek a lower power heater cartridge.


  • administrators

    I agree with everything that @deckingman said in his post.

    Additionally, if the problem is that when you print with one filament for a while and switch to the other, you find that it is jammed, then this is probably caused by not retracting both filaments at the same time. The fix is to use firmware retraction.



  • @jkaechler Did you run a PID tuning after changing the hotend? I have bought a e3dv6 clone and the heatbreak was rough in the interior. Polishing it helped.



  • The heating fault actually turned out to be a messed up configuration in my slicer. Cura was still trying to do something with the second tool, and that was apparently confusing the firmware and causing a heat fault.

    When i reset Cura back to the single extruder configuration, everything went immediately back to normal.

    Regarding the jams in the dual extruder, the heat creep and retraction issues seems like it makes a lot of sense.

    In your collective experience, would I be better off with a Y-splitter arrangement like the Prometheus hotend, or the 2 in 1 out arrangement like the cyclops?

    I defenitely want a single nozzle arrangement.



  • @jkaechler said in Hotend woes and heater faults:

    In your collective experience, would I be better off with a Y-splitter arrangement like the Prometheus hotend, or the 2 in 1 out arrangement like the cyclops?

    I defenitely want a single nozzle arrangement.

    Although I have no direct experience of any Y splitter type, my vote would be for a 2 in one out arrangement but it kind of depends on how the "Y" splitter type works. If it's like the Prusa MMU then I believe you have to retract one filament before inserting another. Given the dangers of drawing molten filament back up into the heat break, then I'd have thought the safest thing to do would be to let the hot end partially cool. All that would mean tool changes will take some time. On the other hand, with a 2 in 1 out hot end the "unused" filament will be kept at print temperature for extended periods of time, and if the filament is PLA, then it will hydrolyse (become more and more runny). So when you come to use it, you'll need to firstly purge 20mm or so. On balance, I would still favour that over completely unloading one filament and loading another. Just my twopence worth............


 

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