Printhead jammed ... sort of?

Hi, All:

My brand new LulzBot mini was working fine for a while, but now, even though I can still extrude filament, when I try and do an actual print nothing comes out. I am not mechanically inclined, but any help would be appreciated!


that usually means the idler arm tension springs aren’t tight enough, or you are too close to the bed at start. To check the idler arms, make sure the distance between the washers on either side of the springs on both arms is 8mm or less from washer to washer.

The surface height should be fine with default settings, but you can try playing with it by adjusting the Z offset setting in Cura.

Thanks for the reply, piercet. I contacted Lulzbot technical support – the best support ever! – and they had me clean a bolt connected to the drive gear – it was caked with filament and I guess couldn’t get a grip. They also mentioned the idler arm tension springs – suggesting they should be 5mm betweem the washers.

Hi - I’ve got an extruder back at Oleph for warranty for stripping out filaments. They suggested 5 mm inside washer to washer…actual spring compressed width. I have printed many objects and materials but now am having a huge failure rate on the Taz 5. I since have been told that 0,35 nozzle jams alot so I went to 0.5mm nozzle. I now have a Brand New extruder to keep machine running and couple hours into 20+ hr print just stripped out again. Material Matterhackers Pro PLA 2.85mm consistent.

In your experience, is that extruder compression value too “tight” @ 5mm as mprogers was also told? I am understanding that if too close to the bed, pressure can back up and cause stripping out on hobbed bolt, and this print started pretty high up. Used their “2 sheet” distance, dead level bed (@ ea corner…), etc.

I’m really getting frustrated, reverted back to cura only, etc in hopes of finding one variable causing the issue!

The only other thing is I use Octoprint, which I haven’t seen/read to be an issue on the Taz printing??? It’s a Pi2 so not underpowered I’d hope/guess either.

Any feedback from another user would be greatly appreciated as I can’t fathom what is actually happening :slight_smile:

I apologize as I read this was for the Mini After posting… But seems to be using the same basic components for the extruder, I’d assume steppers, etc??

I recommend a larger fan for the extruder heat break. Do some searches here for “heat creep” to get more background. Many people printing PLA have reported dramatic improvement (or complete elimination) of PLA jams by going to a larger fan. Note that Aleph has moved to a larger fan and shroud design for the Taz6 as well.

There are some good duct designs on Thingiverse that easily adapt a standard 25mm (or larger) fan as replacement for the little “blower” style fan. Here’s one good one created by someone who is also a forum member here:

ScottW -
Got it!

I actually came across his item and contacted him in the meantime too and he’s said it’s helped many people alot :slight_smile: I appreciate the response - quick - and consistent with someone else means alot!!! I’ll order up fans now… I wish Aleph would just supply to me since it’s their issue and I have extended warranty, relatively new machine… etc… I can’t believe after sending 2 extruders back and ordering a new one to keep machine up in meantime they didn’t even bring this up as a possible issue???>???

Have a great day and again appreciate more than you know!

Glad to help, and while I cannot guarantee that heat creep is what you are seeing, the symptoms you describe are consistent and adding a larger fan is pretty easy – so that’s what I would try.

An alternative – and what I personally chose to do – is to just avoid PLA. It is a great material, but it is sensitive to heat creep jamming AND it can create a serious clog if you accidentally set HIPS/ABS/PET/Nylon temperatures with PLA still in the nozzle from a previous print. Don’t ask me how I know this… :sunglasses:

Yes!! I understand your “conditional guarantee” :slight_smile: and am pretty sure this HAS to be the problem since I’ve tried everything else. I’m fooling with the co-poly’s, n-vent,etc. But they are $$$. Do you like/use abs much? I don’t have an enclosure so I’m pretty much out from printing ABS most items I would print.

I don’t think the “perfect” material exists. I do use ABS a lot, but I have my mini enclosed and even with that can sometimes have splitting problems with certain structures, like tall thin walls. I use HIPS for a lot of things; it is inexpensive and has fewer print problems than ABS but is not as durable. I really like PETG for ease of printing and strength, but the “shiny” appearance isn’t right for every part. I’ve had good luck with Taulman910 for high-strength items, but it can be tricky for small parts due to cooling requirements. I found Ngen very similar to PETG, but more expensive, so have not used much of it.

None of them are right for every job. Lots of choices, and it’s complicated by the fact that the same material from different manufacturers, and even different colors of the same material from the same manufacturer, can behave a bit differently. I don’t think there is any way around a certain amount of “trial and error”. :smiley:

I hear you! Very true on all of your points. I have seen the same thing in all of my experiences so at least I feel better knowing that! I have three new 25mm hot end fan mounts ready to roll now! Just need the fans and ready to eliminate some heat creep!

Have a great day and thanks again for your feedback/input!!


+1 for the fan upgrade! I was experiencing similar issues on my Mini and the filament cooling fan upgrade did the trick. No jamming since the upgrade. You’ll notice that Lulzbot made the fan upgrade on their new Taz 6. :wink:

Yes, they actually mentioned that when I called in and asked what the upgraded advances were. I have in a pretty climate controlled (relatively speaking) area but ambient I’m sure has gone up over the past months which correlates to the # of issues with PLA as well! Got my little 5V fan coming in today, part all printed in nice nVent and ready to throw on some pins and go! I hope to be printing PLA again for the Kids stuff where the co-poly isn’t required :slight_smile: