PLA jamming on TAZ 4

Hi guys,

I realise that there are already a few topics about PLA jamming due to heat creep and so on, but as I read through them, most of them were resolved by mounting a fan, but I have a TAZ 4 with a fan already on it stock and the prints are still clogging, which results in the filament grinding on the extruder and not moving on. Even printing at 185°C creates these problems, could increasing the temp (and consequently lowering viscosity) help? Does anyone else have these kind of problems on a TAZ 4?
I’ve been toying with cooling settings in Slic3r and using settings as recommended in other posts but it still jams.

(using blue PLA bought from Lulzbot, just in case it’s relevant)

I’m printing the same filament at 180, with the fan as well with little issues when printing at 80-100. How fast are you printing? It may help to go faster.

I use mostly the default Slic3r profiles from the TAZ 4 page, for the fine setting and some small details I actually lowered some of the speeds there to make smaller details better. As an estimate, what do you think is an acceptable speed for a relatively fine detailed print at 0.14mm?

I also had repeated jamming with the blue PLA on my TAZ 3, even across a variety of tension adjustments, and temperature at 185. The last time it happened I pulled the extruder apart to see if there was a problem. I didn’t see any obvious problem, but as I was playing around with it I noticed that the filament was very tight in the PTFE tube in the extruder. It seemed like the curvature of the filament, combined with its stiffness, might have been causing it to bind in the tube. I haven’t had time to go back and re-visit this, but I have since been using a different PLA filament with absolutely no jams. I wonder if anyone else has noticed this or could provide opinions from more experience.

If you encounter this again, please let us know, we may ask to see what the internal diameter is on the PTFE insert.


I had a few more jams with PLA, so I pulled the extruder apart again. The internal diameter of the PTFE tube seems to be plenty big enough. I also noticed that once the end of the filament exits the other end of the tube, it feeds very smoothly.

I installed the new fan shroud/duct described in this thread:
and that seems to have taken care of the problem. Now I can use these PLA filaments to print at even very low feed rates. I left some more details in that thread.

I highly recommend to AO that you check out this design and consider using it for the TAZ fan kit.

I had the same problem until I adopted the fan shroud you linked.

What I would actually like to see Lulzbot adopt is a second fan on the other side of the extruder that blows exclusively at the Buda nozzle from just above the heater block up. This way I can keep that fan always on and use slic3r to adjust the speed of the blower fan that cools the prints. I like to keep the blower off for the first layer but can’t do that if the fan is shared with the nozzle cooling functionality.

I’m working on a new fan shroud to do just that on the other side and hope to have it up online soon.

Good idea. Please update us when you put it online.

Put up an early version of the shroud I made in scad. It works well, I just want to tweak its positioning and air direction a bit farther but its a good start. Will upload a photo with the part once I return home from my current business trip.