Changing filament (and detecting when it's running out)

Discussion in 'BigBox General Chat' started by Alex Stevenson, Sep 4, 2016.

  1. Alex Stevenson

    Alex Stevenson Well-Known Member

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    Well, I was just over 9 hours of a 10 hour print, and, after a few minutes, noticed that the filament had completely run dry... just a tad frustrating, as it was an absolutely perfect print up until it ran out, and started "air printing".

    However, my first concern when it happened wasn't the unfinished print, but what kind of mess might have been left in the extruder, as there was filament just barely sticking out from the "nubbin" (can't remember the technical word for the upside-down V protrusion just below the extruder motor. I was really concerned that it would be: a) extremely hard to pull back out, and b) potentially block if I try pushing filament in behind it.

    Bit of background: I've only ever changed filament before, and I did it by raising the temperature of the extruder to around 100 degrees, and carefully pulling it out. This seemed to work perfectly, and came out all in one part.

    I finally got it to work: I cut the filament at a right-angle (hoping that there was more chance of it pushing the old filament through), setting the extruder to 210 degrees, and manually feeding (using the front-panel) the filament through. I put a small mark on the new filament to ensure that it was feeding through evenly.

    I have a few questions, if that's okay:

    1) Is my approach to filament changing, and what I did in this case okay?
    2) Is there a (better) way of telling if filament is about to run out, other than watching it?
    3) Has anyone encountered a blockage when changing / running out of filament? Is it as problematic as I imagine?

    I have another question about the extrusion calibration (going through half a dozen iterations, changing esteps, I still can't get exactly 20mm)... I seem to end up increasing the e-steps by 10 each time, and still ending up with 24mm left after the extrusion 0 test print. Touch wood, it seems to work fine anyway...

    Many thanks in advance.
     
  2. Kanedias

    Kanedias Well-Known Member

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    There are third party gizmos that can detect if a filament is missing or jammed and pause your print. Or you could deign your own!

    What you're describing sounds fine, you could have equally just fed new filament in behind the existing remnant.

    Yes I've got blockages removing filament, and it generally ends up in taking the hot end apart. It's no big deal, 10 minute job all in.
     
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  3. Alex Stevenson

    Alex Stevenson Well-Known Member

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    Thanks for the quick, and reassuring, response @Kanedias

    Actually that's what I meant (although I didn't explain that part well) when I mentioned manually feeding it through - it was pushing the remnant out.

    Is that with the Titan upgrade, or the original assembly? I think I should step through the process at some stage as I was thinking this process would be much more complex.
     
  4. Kanedias

    Kanedias Well-Known Member

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    Original assembly. Removing the heat break from the extruder is just 2 screws. It's a bit more of a hassle for the Titan I think, that's one reason I haven't upgraded. I doubt you'd get into much trouble by continuing to feed new filament in after the old. If you're using different materials you set the temp for the higher ones obviously.
     
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  5. Alex Stevenson

    Alex Stevenson Well-Known Member

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    Oh that's interesting. I thought the Titan upgrade was much better for those kinds of things.
     
  6. PsyVision

    PsyVision Moderator
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    The hybrid titan was a bit of a faff to sort out blockages (IMO). The dual titan is better as there are effectively two "print heads" in a container, you can just pull them out and take them apart easily.

    I wonder what their new solution will be for the dual head design.
     
  7. Alex Stevenson

    Alex Stevenson Well-Known Member

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    That's what I'm really looking forward to hearing about. Not sure about the idea of two independently moving heads, but that's certainly intriguing.
     
  8. Old_Tafr

    Old_Tafr Well-Known Member

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    There are splicing tools that melt two pieces together too
     
  9. Alex Stevenson

    Alex Stevenson Well-Known Member

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    Yeah, they're pretty intriguing too (especially when they blend colours). Although wouldn't you still need to recalibrate when changing? I thought even different colours in the same material could require different estep settings...
     

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