TAZ 5 extruder clogged printing fine detail

I am printing with PLA on my TAZ 5 with standard extruder, 3mm PLA filament, Hexagon hot end, 200C, 0.5mm nozzle. Usually it works fine, no problems and I have dozens of successful prints. However when I try to print Elliptical Gears (from Thingiverse) it always clogs.

The problem seems to be the tiny sections of the infill on the gears. It looks like the amount of extrusion required per tiny segment is smaller than the motor steps so it rounds down to zero, doesn’t feed at all. After a while of this, it doesn’t like being stopped while heated and everything clogs, filament strips etc. I can unclog it OK (getting good with practise) so I don’t need advice on that, just how to prevent it clogging in the first place.

Fans are working fine and it doesn’t happen on any other print job (including connecting rods for the elliptical gears).

Has anyone else experienced this effect? Is it inherent in the 3mm extruder? Would a new 1.75mm extruder (eg Titan, Hemera) be better?

IMO, you shouldn’t need a different extruder and switching from 3mm to 1.75mm shouldn’t be necessary.

I think some tweaking of slicer settings could minimize the problem. What slicer are you using (include version number)? Can you provide a sample .stl file and the .gcode output?

Alternatively (i.e. if tweaking slicer settings doesn’t work), a different sized nozzle might help but I don’t know if you can find one that’s compatible with your TAZ 5 extruder.

I have multiple tool heads for my TAZ 6 including 3 standard extruders with different sized nozzles (.2mm, .35mm, and .5mm).

Hi Morgan, thanks for taking an interest

Cura Lulzbot Edition 3.6.20. Settings are standard except layer height 0.1 or 0.2 but they both fail. I have also slowed first layer for better adhesion but that prints fine anyway, it only goes wrong after a couple of layers of infill. Gcode file is attached.


(Attachment LTAZ5_one_gear_no_center.gcode is missing)

The attachment didn’t make it. I’d like to get the .stl file as well as the .gcode file so I can look at what the slicer generated and then experiment with some settings.

Hi Morgan,

Sorry I’ve been busy - house guests.

Attached is the .stl, I will send the g-code separately in case it gets stuck.

Meanwhile I think I have found a possible cause. The X axis bearings are very loose. In X the lower rod bearing is loose, top one OK. This means that when it moves in Y, the extruder head can flop in Y direction. I think that with small details to print the flopping about means it doesn’t move off the one place, blocks up etc.

Y bearings are also pretty sloppy but I’m not sure that is having any bad effect at present. Anyway, I’ll plan to fix all the bearings first then try again. I’m thinking recirculating ball type. The plastic bearings I understand need to be pressed into a hole and this machine has split bearing holders in some places. Noise doesn’t matter (I can close the door to the study).


one_gear_no_center.stl (1.93 MB)

Sounds like a good plan. I’d be careful changing the bearing type. If the bearing holders are not split by design, you may need to print (or have printed) some new ones. The files should be available on the LulzBot site.

Thanks Morgan. I’ll check it out before selecting bearings. I’ll leave it at that for now, raise another query if it is still not working after bearings etc are resolved.


Just to satisfy my curiosity, I printed this part on my TAZ 6, Standard Single Extruder V2.1, 0.5mm nozzle, Marlin_TAZ6_Universal_2. firmware.

I sliced it with CuraLE 3.6.35 using the default material settings for Polylite PLA (layer height .25, first layer .425, 20% infill). I did change top layers and bottom layers to 3 so there were more infill layers.

While the print was successful, my heart skipped a beat when I took the part off the bed as it obviously wasn’t round. I had to go back to CuraLE and adjust the view to straight down to verify that this gear is oval! I have attached the .gcode output in case you want to examine it in detail.

one_gear_no_center.stl (1.9 MB)
one_gear_no_center.gcode (2.2 MB)

Thanks I think that confirms there’s something mechanical wrong with my printer. I’ll add fixing that to my list.