Filament Blowing out before reaching extruder

Hi All, I've got a problem that I thought someone must have faced before. I appreciate your help identifying and solving my issue and offer my thanks in advance.

My printer has developed an issue and I'm not sure of the cause. The extruder stepper is pushing the filament into the extruder but the filament instead pushes out to the side, this ends the print. The print will go on for about 90 mins without issue before this happens and it seems to be happening every time.

I thought it might be a clogged nozle from dust, so I cleaned it out and dusted off the filament, but no luck; it happened again about 90 mins into the new print.

Does anyone else have any thoughts to offer? Have you seen this before? How did yo uget around it?

Thanks.

... its normal, when the heat creeps up and start to melt ever more of the filament and the gap betwen hot- and cold-end is too big ...

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

It's not normal.

It's a bad extruder design, maybe combined with thermal problems. There should be no gap between the filament drive gear and the tube that guides the filament down to the hot end. The E3D Titan has no gap, and is pretty cheap, but avoid knockoffs. If you want a great extruder, get a Bondtech BMG.

If the hot-end temperature is too low (or you're trying to print too fast), it will take extra force to get the plastic to extrude. That can lead to the filament buckling in the gap in the extruder. Try increasing the hot-end temperature. Also, if the pinch roller pressure on the filament is too great, it can squash the filament and give it an excuse to fold. The pressure should be high enough that the drive gear never chews a divot into the filament, but not so high that it crushes the filament. Finally, the hot end should have a cooling fan that runs all the time. If heat creeps up the heatbreak (or motor current is so high that the motor and drive gear are getting very hot) the filament can soften, once again giving it an excuse to fold in the gap in the extruder.

See: [drmrehorst.blogspot.com] and [drmrehorst.blogspot.com] and [drmrehorst.blogspot.com]

Edited 1 time(s). Last edit at 02/20/2021 08:35AM by the_digital_dentist.

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Thanks,

I'll try reducing the gap by lifting the throat up, I noticed quite a bit of wear in the throat so I don't know if that could be causing the issue. I'll replace the throat and nozzle at the same time. Then I'll consider replacing the whole extruder with a beter model.

I recently upgraded to a heated bed, so maybe the extra heat in the system could be causing a softening. I'll look at that as well.

... oh, it's "normal", if the design/assembly isn't optimal -- you could read through our "developing" discussions from 2006 on

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

That gap in the extruder will make it difficult or prevent you from printing most flexible filaments, too...

---

Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]