Pig-tailing with new nozzle

I’ve been struggling with extrusion issues for a while now. I recently bought a few new nozzles because I figured maybe I had damaged the one that came with the printer. But the issues have persisted. Here’s what I saw with new nozzles.

For PLA:

  1. Install nozzle following https://forum.lulzbot.com/t/taz-5-hotend-clogged/1585/1
  2. Print successfully with blue PLA , 3mm eSUN
  3. Run out of blue PLA (was the first spool I bought)
  4. Switch to natural PLA, 3mm eSUN
  5. Print failures!

The hobbed bolt ends up cutting into the filament.


For HIPS:

  1. Install nozzle following https://forum.lulzbot.com/t/taz-5-hotend-clogged/1585/1
  2. Extrude HIPS (3mm eSUN I) into air. It pig-tails!
  3. Try a print anyway…

Here’s the first 5mm extrusion with eSUN HIPS from a brand new nozzle:


I’ll update with how the print attempt goes.


I have tried changing the tension using a spacer (https://forum.lulzbot.com/t/hobbed-bolt-clogging-filament-stuck/1739/1), by feel, with a ruler, etc. It’s either too loose or works well enough until things fail in a print.

Haven’t found any mention of a pig-tail issue with a clean (it’s new!) nozzle. Any help and things to try appreciated!

I have seen that a few times. It has always been an obstruction in the nozzle. Try some cold pulls. If that doesn’t work, pull the nozzle and soak it in a solvent that will dissolve the plastic.

ABS dissolves in acetone. PLA dissolves in SCIGRIP 4 and HIPS dissolves in limonene.

I have seen that happen with too low of temperatures as well, usually when purging. When switching from HIPS to PLA did you purge 70-100mm of PLA at 240 to clear the HIPS? (be sure to drop the temp back to PLA temp as soon as filament stops moving)

This extrusion was with a new nozzle. There had never been any other plastic in it.
Fair point about temperature, though I have used this specific spool of HIPS in the past without issue. Given this plus problems with other filaments I expect something with the printer to be wrong, not something with the filament. I did lots of rounds of cleaning my original nozzle before buying a few replacements. No amount of cleaning helped, though I did get it very clean a few times with cold pulls and acetone soaks (after using ABS).

When I put on this latest nozzle I did push a length of HIPS through the hot end while the nozzle was off and the hot end was at 165C. That removed the remaining bit of natural PLA that was in there.

I had my Mini for 3 months and had maybe two jams, one I attributed to a jammed up feed off the spool. Printed 100% ABS. Either you have a run of incredibly bad luck or bad filament. I always checked the hobbed bolt teeth and cleaned when needed, which was about every other print.

What machine and what size nozzle?

Fyi, sometimes even the same brand and type of filament will require a slightly different extruder temperature or speed to work properly.

I have the TAZ 5. Using stock nozzle which is listed as .35mm but I think is actually .3mm. I bought some replacements that were sold as .3mm and they’re identical to the stock “.35mm” which has a big number “3” etched on the side.

Anyway, I might have figured it out. Last weekend I dismantled my extruder, taking all but the hot end apart. Found the small herringbone gear for extrusion is wearing down. Also, extrusion was binding a little bit. When I put it back together I didn’t tighten the hobbed bolt as much, so it turns much easier.

These are all red herrings though. I think the actual problem after having eliminated everything else is where I have my filament. Some time ago I printed a spool holder and mounted it inside my enclosure. It was working fine, but I didn’t have my enclosure completely sealed yet. Once I was able to seal the enclosure I think is when problems started happening. Why? I think the spool of filament was heating up, softening just enough that the hobbed bolt was able to eat through it eventually.

Time will tell. I moved the filament outside of my enclosure and cleaned my nozzle in acetone (had been printing ABS only in this one). Print of the new small herringbone gear just finished and it looks great. It’s a small print though, I’m going to try something bigger that I know has failed in the past.

Thoughts on pig-tailing: I’ve seen this only with HIPS. I think it might be from using OctoPrint, the extrude speed is maybe too high? At this time I’m not going to be printing in HIPS and I’ve moved back to printing from the printer SD card.

FWIW my Taz 5 did this with HIPS from day one* and eventually stopped after I dismantled the hot end and soaked the nozzle in acetone to remove a clog. Either it was obstructed from the start or my rubbing the bore with a toothpick smoothed things out. Either way, it’s a champ now.

*Maybe day two, honestly. And it’s my first printer so I might have clogged it myself? I’ll never know now that it works.

I changed my nozzle today and noticed the exact same thing with ABS. I was trying to do a calibration of the extrusion rate using Pronterface. Everything was hot, at 240, and my 10mm extrusions looked beautiful. Then I set Pronterface to extrude 100mm. It started fine, then pigtailed about in the middle, and then just stopped extruding while the hobbed bolt chewed up the filament. I’ve noticed this before when using Pronterface – like it is trying to extrude too fast.

Perhaps a slower extrusion would be worth trying? My problem is – I don’t know how to force a slower extrusion rate.

Agree. I realized last week that I started seeing a problem after switching to OctoPrint. Extrusion is MUCH faster with it and there’s no way to control it. So I have switched to using the printer controls for initial extrusion. At slow speed, no problems with HIPS. So was just speed.