I’ve got a Taz 6 that’s probably about 8 years old with a slightly newer tool head using Cura Lulzbot Edition 3.6.3. Lately, when I print with retraction enabled, the filament will often stop extruding partway though the print. Sometimes it starts extruding again several layers later making a big mess. The problem seems to go away when I print with the retraction disabled, but that leads to messy prints and ignores that possibility that this is symptomatic of another issue. There are some other posts on the forums about this issue, but they don’t have detailed enough solutions for me to follow. Can anyone give me specific instruction on how to fix this, or is this part of a larger problem?
Jamming partway through a print is usually caused by a combination of factors. One of those factors alone may not be enough for a jam, but a few of them together can do it.
Heatcreep: Going too slow (softened filament isn’t pushed soon enough), too many retractions (heat pulled by the filament upward), too hot (more heat transferred to the heatbreak), too cold (more resistance for the filament to push through)
Clogged teeth: A vicious cycle, where anything in the teeth reduces pushing force and reduces contact points, increasing chances of more stirpping of filament, clogging more teeth.
Clogged nozzle: Increases backpressure on the filament, leading to stripped filament from the gears and increasing chances of heatcreep causing a jam.
Z offset too low: Increases backpressure on the filament, leading to stripped filament from the gears and increasing chances of heatcreep causing a jam.
Flow rate too fast: Increases backpressure on the filament, leading to stripped filament from the gears and increasing chances of heatcreep causing a jam.
So… it’s a lot of potential causes that you need to work through.
Thank you for the reply, I should have stated originally that I am using a 2.85 mm PLA printing at 195 C with a SE 0.5 mm Tool Head. I’m using 3DXTech ecomax natural PLA. The recommended print temp is 190-220. This is not the original tool head because that one get wrecked somehow. This printer is at my work and was not purchased by me, though I am now the only one using it.
I have tried a variety of temperatures and print speeds with no luck. It’s currently set at a print speed of 60 mm/s and then 30 mm/s on the walls and 40 mm/s on the infill. That’s the bottom end of what I’ve tested. Along with print speed, I’ve tried a range of layer heights from 0.1 to 0.43 mm but that doesn’t seem have any effect on the success or failure of a print. I’ve not done this in a systematic style, but rather scattershot attempts to get it to work.
I’m not sure how to check the Z offset. It does an automatic bed levelling before each print. Does that not take the Z offset into account?
I’d recommend updating to Cura 4.13 and flashing the latest universal firmware for the Taz 6. Be sure to record your Z offset before updating the firmware, as it will be reset to default values after flashing. Then restore your Z offset when the flash is complete.
Do some test prints with their default PLA profile for a Taz with the SE 0.5 toolhead and see how those come out.
The bed leveling doesn’t do anything about Z offset. The Z offset should equal the difference in heights between the level of the top of the washers and the top of the bed. With the glass and PEI bed, it is typically around -1.25 to -1.3 on the Taz 6. Octograb bed puts it at about +0.3.
If your first layer is fine, you shouldn’t have to change it, but if you get jams frequently in the first 1-3 layers, it’s worth checking.
That’s really good advice, upgrading the firmware seemed to resolve a lot of odd jams my rehabbed Taz 6 was having. I haven’t explored many of their other material profiles and have found cloning the Generic one and making new profiles works best. I bounce around between Ultimaker 2.85mm, Colorfabb (which seems identical in manufacture but I can’t get either party to endorse that!) and Polymaker materials.