Troubleshooting Budashnozzle 1.2 with 0.35 nozzle

I’m still playing with the Natural ABS Filament (and having fun), but now I think I have a problem with the extrusion.

I printed one plate of six small crossed 3D pieces with success without encountering any problem (see fist image). But when I started the second plate, 25 minutes late or so, I had problem with extrusion. Often the filament was not coming out, which for some of the piece cause adhesion problem, for the other, the piece looks OK, but while printing I notice that plastic would sometime stop coming out. (see second image)

The problem is not only after retraction, it also started (or stopped…) while already laying down a line of the cross. What make me think it’s is more a hardware problem that a software (not that it could not be worked around with software), it is that the first plate printed OK, but not the second.

I had printed about 16cm^3 of plastic before starting those print. Always at 230C and (exactly the same config than this post except for less retraction length) printed. I had a bad feeling that I had the same problem I was having with cheap filament bought from an other source (The Natural ABS Filament is from LulzBot). So I disassembled the head and you can see that the filament filled the head up to the peek, even between the peek and the PTFE tube tube. (see third image) This must be because the filament does not goes out has fast has I want it to go and just accumulates in. Then I assume this made more resistance because the filament up there is colder.

Should I not use 3mm filament with a 0.35 nozzle ?
Should I increase temperature ?
Should I go slower (when apparently a solution for other problem would be to go faster) ?

I’m starting to think that I will drill my 0.35mm nozzle to 0.5mm and I’m here in hope that you can talk me out of it.

Ilmion



You should be able to reach 75-90mm with the 0.35mm nozzle. There’s a couple of things that I would like you to check if you don’t mind. The third picture concerns me. I’m wondering if your Budaschnozzle falls under this service bulletin. Would you mind checking the length and the inner diameter of the PTFE tube? Are you using a fan? I would not use a fan when printing in ABS. Your second picture looks like it had an issue with adhesion on one of the objects. The prints in the second picture look good aside from that. What happened before you disassembled the hot end? I do not recommend trying to drill out your nozzle, if you don’t get it exactly right and square your prints will suffer.

Edit: The blockages that developed were related to the service bulletin. A new replacement PTFE tube is on the way!

Seeing that the problem only happens on the right side of the print makes me think of a different cause. Depending on how your spool holder is set up and extruder idler tightness, your extruder may have a hard time pulling in the filament. I have seen this behavior when I forget to tighten my idler enough after a filament change or if the filament is spooled in a way that leads to tangled filament that won’t be pulled in easily. The latter also leads to skipped steps on x or y axises.

That is something that I have tough while printing, so I checked the filament tension many time and it was always ok.
Also, I don’t think that the extruder not being able to pull the filament would cause a clog in the head.

I cannot wait the new PTFE tube to arrive, thank for the excellent costumer support. I will come back here when I will have experimented with the new tube.

The replacement tube was receive last Monday and I have printed enough to say the my problem is solve.
So : HURRAY !