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A while ago bought a Bowden extruder to replace the old built-in one (It was malfunctioning or something that I cannot remember well). This one in particular has been acquired:

The extruder set

The thing is, that almost a year has passed since the printer did something rather than getting jammed and not work properly. The extruder itself seems to work properly, when I heats up and push the filament by hand seems to pass properly.

When assembled and start to print, the printer at first seems to work, but after a minute or so, it stops extruding (gets jammed or something).

The last time that I removed the filament and I've found out that it was coiled inside (Very strange):

Coiled ugly deformed filament

My first thought was that the filament was thinner than the extruder's specs, but the seller says that is for 1.75mm, and all my filaments have that diameter.

What I am missing? Something maybe that is not properly mounted?

The product is not official, bought on Amazon (I didn't know about e3d v6).

Printing temperature should be 180ºC but I've seen now that Cura sets the first layers to print at 200ºC. Material: PLA

My printer is a BQ Prusa i3 Hephestos.

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  • $\begingroup$ What material are you using? Also what temperature? After you remove the twisted/coiled filament, is the nozzle chock-full of previously melted material? $\endgroup$
    – Carl Witthoft
    Dec 7, 2018 at 13:41
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    $\begingroup$ is it a genuine e3d v6 or a chinese aftermarket? What kind of printer do you use? Did you follow the assembly instructions and hot-tighten it? $\endgroup$
    – Trish
    Dec 7, 2018 at 13:43
  • $\begingroup$ I've added additional data to the question. About the instructions... well, I didn't know about the original model and the seller does not provide instructions so, I just tightened them in cold (but nothing more). $\endgroup$
    – Sigma Octantis
    Dec 7, 2018 at 15:15
  • $\begingroup$ What kind of material is it? Printint PLA 1t 180° is a little low, ABS is to be printed even hotter. $\endgroup$
    – Trish
    Dec 7, 2018 at 15:24
  • $\begingroup$ Do you use an all-metal heat break? (e.g. is there a liner in the heat break or not) Also, what is the scale of the filament image, e.g. id the filament 1.75 mm on the thickest parts? $\endgroup$
    – 0scar ♦
    Dec 7, 2018 at 18:55

2 Answers 2

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As long as there is no more information about the printer itself (I searched a bit and around half of buyers were severely unhappy with the result), I'd advise you to make a full check of all of the important parts that make up a 3D printer making ok prints:

  • Are motors moving as they should?
  • Is the extruder actually extrude filament when told so (do the check "2cm" = 2cm extruded)?
  • Is the Z calibration ok (<- VERY important, will make tons of weird problems if extruder is too close to the bed, believe me, don't skip out on this one. A blue tape or not a blue tape makes a world of difference).

Also of course check your filament (no variations too big of the diameter).

For the temperature, IMO go for the higher for starters (maybe no, see "heat creep" below), you won't be able to bridge / less good quality etc. but you'll get pieces done.

NOW, the image you posted shows a twisted (I don't know how to handle that) or a grinded filament.

When I say 'grinded' I mean that the filament got stuck somewhere (see below) and the (cogged) wheel pushing the filament is so strong that is grinds off plastic from it, forming waves on the filament. Eating away parts so it looks like your photo.

If that's the case, then you should check out "heat creep", it's basically the heat in the lowest part of the extruder (the thing you call a bowden extruder) will heat up the filament and make it melt Above the heat block, making a blob of half melt plastic stopping the forward movement of the filament. This is usually mitigated by two things, that lacks more or less in cheap chinese knock offs: * The fan and it's cooling efficiency (the fan must blow when the heat block is hot, even if there is no printing going on. Even if the heat block is no longer heating. I shut the fan off at around 60°C). * The Heat break: if it's heavy it will conduct too much heat, if it's thin it might work but will break easily.

3D Printing is not obvious or easy, but spend some time and it'll start to work well!

Cheers

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  • $\begingroup$ Thanks! I'll check out tomorrow for the extrusion amount to see if really is extruding what it should, The Z callibration should be OK (I use a glass heated bed and test with a paper sheet) the axis motors work more or less Ok but I'll check out if they do so. And also I'll tell you if the fan is really cooling what should or not. $\endgroup$
    – Sigma Octantis
    Dec 8, 2018 at 22:19
  • $\begingroup$ A late remark, do check out the spring or whatever system you have, that pushes the filament onto the cogged wheel (or similar). If it's too loose, the extruder motor could grind the filament and not be able to push it correctly. My bet is on the fan though but who knows! $\endgroup$
    – Valmond
    Dec 10, 2018 at 11:04
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If you converted a printer from direct to Bowden feed, it is possible that the cold side of the hot end is too hot, and you are suffering from heat creap. Simple, less expensive printers often use the extruder stepper and the extruder stepper mount as part of the cooling system.

If there is any sort of a heat-sink on the cold side of the hot-end, try to rig a fan to blow through the heat sink. If there isn't a heat sink, find one and add it. Heat sinks made for round transistor cases can sometime be fitted to the cold side. A little heat sink great, a couple of transistor heat sinks, and a fan may completely solve your problem.

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