I have 6 TAZ6 printers that all have SE 0.5mm toolheads on them and these toolheads drive me crazy: they experience loss of extrusion because of filament grinding all the time. Like multiple times a week. For context this is in an academic setting and individual student users are setting them up, so in all fairness they are probably doing some things wrong. But often when I check, or am called upon to fix things, I can see no obvious reason that leads to this.
I assume the most obvious culprit that’s within our control is the idler tension. If we find the hobbed wheel is grinding filament, is it more likely that the idler tension is too high, or too low? Official directions from Lulzbot on this literally don’t exist (prove me wrong) and when I’ve asked tech support, they give me a set of filament change instructions that doesn’t seem to be public anywhere, and say to tighten the knob until it’s tight, which is obviously subjective. This often gets the idler spring nut in the middle of its travel. But again, should I be erring on the side of too tight, or too loose, or how do I know what’s just right?
For further context, we print almost exclusively with PLA (Polymaker Polylite, in case it matters), and so I wonder if this is just a heat creep thing and if these toolheads are just poorly designed. What can I do to like these toolheads more than I hate them?
I’ve got a SE 0.5mm that’s been going through full rolls of PLA for days at a time (about 56 hrs per roll, for about 3 weeks now). Heat creep with PLA isn’t an inherent issue with the Titan Aero.
What is a common-enough issue with them, however, is defects that cause misaligned teeth. The drive teeth are not in alignment with the filament path just enough that they’re constantly pinching the filament where they generate dust that clogs the teeth, increasing the chance of stripping the filament.
This misalignment can be caused by excess pressure, or just a bad cut.
Drop a small washer in the hole to shift the teeth over, order new gears, or, like I did, just say goodbye to single-gear extruders if possible. If you get a good one, it should be fine, but single-gear extruders (at least the small ones - I hear good things about the LGX) are just a weak point.
I actually just mounted a 2.85mm Orbiter on my old Single Extruder in place of the Wade extruder on my personal machine. I still use the Hexagon hot end, but with a CHT-clone nozzle in it. With the BLTouch attached, you’d laugh at the Frankenstein of a monster it appears to be, but I am pushing TPR filament (which makes TPU look like PLA in terms of hardness) through a 1.0mm CHT nozzle at speeds that are equal to what I could do with PLA with a stock Taz 6.
I believe “official” instructions on idler tension were present for the TAZ 3 and TAZ 4, but may have gone by the wayside since then. But they are basically the same for all the herringbone drive toolheads, 5-10mm of visible threads of the thumbwheels when filament is loaded. So, 7-8mm is the sweet spot.
You reminded me, we never clarified, is it the SE 0.5 toolhead, or the Single Extruder with a .5mm nozzle?
The guidance I gave was for the SE 0.5 based on the Titan Aero, not the Single Extruder. If the Single Extruder is grinding… That’s fairly par for the course with PLA. The extruder was designed around ABS and other filaments that weren’t sensitive to heat creep, so PLA generally fails with it. Tensioning guidance is to check your filament. Grooves in the filament are good, but if there’s any crumbling of filament, it’s too tight.
Yeah, it’s unclear whether tk4b is referring to the hexagon-hotend single extruder 0.5 toolheads that shipped from the factory or whether they’ve been replaced with E3D Aeros. My advice was for the former, the stock toolheads. For the latter, I have had a number of discussions with the fine tech support folks at FAME 3D abut the proper adjustment of the thumbwheel on the Aero, and there is no “factory specification” on these. I typically tun them full clockwise (loosened) when loading, then back off 2 full turns for the spring preload of the idler. That seems to work fine.
Hi, to clarify, I used the language Lulzbot uses in naming this toolhead: SE 0.5 (this one). This is a dumb name for this toolhead, because obviously that’s easily confused with the “Single Extruder” toolhead. They should have called it Aerostruder V2 or something, because that’s basically what it is.
I appreciate the comments and input so far, but for a variety of reasons I do not believe I have the hobbed wheel offset issue, although that’s a pretty interesting finding. Here’s what it looks like on one of my 6 printers (hard to see, even harder to get a clear picture):
I recall a recent post about how PLA has no business being in 2.85 format since it’s brittle and I may have purchased way too much of it if that is true.
It’s true, but a good dual drive orbiter 2.85 can push it pretty well without needing crushing force. Also a big (.6 or greater) CHT style nozzle helps melt the thick PLA with less back pressure.
It’s about 60$ of parts, more if you step up to a ceramic heater too.
That all said, unless you have a lot of 2.85mm, just swap over to 1.75 for PLA.
Interesting point about the diameter, and of course you’re right about back pressure and such, but this print head is built for and advertised as running 2.85mm filament, so it seems kinda crazy to me that that would be the source of the problem.
Additionally, these are largely being run by students without supervision - they make enough mistakes anyway, no way they will reliably all change their filament settings in Cura to account for filament diameter that’s not pre-baked into the settings. Essentially I want them to set up the correct toolhead and material in Cura, and use standard print profiles, and that should succeed most of the time. But with this setup, they are constantly confounded by loss of extrusion by filament grinding.
The most commen cause of filament jams with PLA are basically trying to push it through the nozzle too fast. This is affected by 3 main things:
Print speed (obviously).
Layer thickness - thinner layers aren’t pushed out as fast
Temperature. Counterintuitively, even though PLA heat creep is caused by the part of the filament that is supposed to be cool and stiff getting warm and soft and thus expanding and getting stuck in the guide tube, running a bit warmer reduces the viscosity and makes it easier to push it through the nozzle.
There are couple other things to check, for example we had a customer that we had sold a TAZ 6 to a while ago that started to get filament jams on gcode that had been working fine for years doing daily production. Maddeningly, they were intermittent as well! On a hunch (their facility doesn’t have great environmental control in terms of debris and particulates), I changed out their nozzle and everything started working perfectly again. I took their old nozzle (after running ABS through it and then soaking it in acetone for a couple days) and cleaned it out, and sure enough, there was a lot of particulate contamination in it.
Another old trick is to run some oil down in there; we used to use canola oil, but have found that baby oil works better, it’s 100% mineral and works at higher temperatures than canola. Basically dip the end of a cotton swab in the oil and wipe it on the outside of the filament for a couple inches above the extruder.
We run both 2.85 and 1.75 machines, and they can both experience filament jams from heat creep on PLA.
You have my interest. I can find the extruder you mentioned on AliExpress, but not sure how to go about making the rest of it. You have plans or can point me to some?
Yes, they run 2.85mm filament, and can technically run PLA (and when calibrated for correctly for a specific formulation of PLA, can do so very reliably). But you have to look at the history of 3D printing to learn that until 1.75mm became the standard, PLA wasn’t common, because, it sucks at 2.85mm. At 1.75mm it’s pretty good, but since there were so many benefits to PLA, they made it in 2.85mm also.
With a well-calibrated profile, it does work, but unlike ABS that is fairly consistent, PLA has had a million different “Plus, Pro, Tough” formulations that change the proper speeds and temperatures greatly. These differences are amplified when running 2.85mm. A lot of the formulations that LulzBot made profiles for have changed or just don’t exist anymore. And LulzBot has been absolutely terrible at making new profiles. You’d think they could buy some of the more common 2.85mm filaments and do a new batch of profiles, but um… they aren’t. For reasons?
If you’re doing things with a bunch of students without supervision, you need to get ONE brand of PLA filament (one color of it would be even more ideal) and delete all other filament profiles. Spend a few hours doing temperature towers, speed towers, retraction towers, and really tune that profile.
Orbiter 2.85mm. Get the one with the PTFE tubing, unless you have some with the right diameters. You’ll have to make sure the extruder is wired to go in the right direction. The extruder comes with the GCODE commands you need to set the proper current to the motor and steps/mm - but if you still have a RAMBO board, you’ll need to adjust them to be in the ###/255 (with 255 being full current) instead of the simple ### = current method used in the guide. I’ve been running an Octopus board for a while, so I can’t tell you the exact ### you need for the current modification.
Adapter plate: Flexorbiter Adapter v1.stl (4.3 MB) This goes between the orbiter and the metal plate, naturally. You’ll need to run the PTFE from the orbiter, through the plastic and rest against the metal of the Hexagon. It’s against the cold end, so shouldn’t ever need replacing. Print in ABS, PETG or PC with the hexagonal nut hole side down. There’s a thin sacrificial layer to let the smaller circles print properly. Just punch through it and clean up. I can’t remember M3 bolt length, but it was something like 8-10mm.
That’s really about all there is to it. New current. New steps/mm. Motor wired in and bolted up. It’s been so good I’m 47 hours into a 62 hour print of this skull bowl using the most flexible filament known (at least known to me) and not worried at all.
I’m about to order the modern V6 components, but I think I’m more limited by the part cooling of the Single Extruder right now than what I’d gain with a modern V6 setup with a ceramic heater and efficient heatbreak/radiator. I’ll probably do something with blowers instead of the axial fans in the near future.
I appreciate the input, but yes essentially I already do this. As mentioned in my original post, we use pretty much exclusively Polymaker Polylite PLA (one color), specifically to reduce these kinds of problems. Lulzbot sells it, they have profiles built specifically for the exact material, and all of our training information points them to define the material this way in Cura.
I hear what you are saying on highly tuned profiles, but should I seriously assume that the default, built-in profile made by the company for this material on this printer with this toolhead is so bad that it causes the problems I’ve described? I find that puzzling and makes me wonder why I should continue messing around with Lulzbots.
Part of what frustrates me about this is I specifically had a discussion with a Lulzbot (FAME 3D) educational sales person about this and purchased these toolheads on their recommendation. We spent a good chunk of money on six SE 0.5mm toolheads believing they would give us consistent output but it’s been a lot of frustration.
Thanks, great information in a clear format. However, the print speed, layer height, and print temperature are not being tinkered with - they are all based on the standard profile in Cura for this exact material.
Good idea about the nozzle health, but we do use the umbrella tents on all these printers and that keeps them fairly clean from any dust. Whenever I do cold pulls, I don’t see much coming out. Additionally, these nozzles (and entire print heads) are less than a year old and have been doing this since we got them.
Interesting idea about the oil - how often would you suggesting doing that? Does it cause adhesion issues? Should the toolhead just be purged for a while when running oil through?
I completely agree that the profiles should be better, but the manufacturers modify their formulas over the years, and the environment that FAME developed the profile in isn’t the same as yours, so there will always need to be some tweaking.
My SE 0.5 toolhead has been running Matterhackers Pro PLA literally for weeks straight without issue. It took tuning to get it that way, but the machine is thoroughly consistent when dialed in.
I agree with Wrathernaut, just because the profiles are “standard” doesn’t mean they are optimum for you! Over the years I have developed profiles that work for me and they may be based on the factory profiles but they are always tweaked. And different geometries need different parameters too. Since you say these machines have been doing this since new, (or at least the toolheads have), that tells you right there - well, we all know the definition of insanity, right?
I suggest trying the oil once every 100 hours or so of build time, and no, it does not cause adhesion issues as long as your z offset is set properly.
Alright so this is still driving me crazy, perhaps even more so now - just today I’ve had 5 printers grind up the filament within the first couple layers of printing, several of them did not even finish the first layer. All of these failures happened with the tensioning knob turned 2 full rotations as suggested above. I have not yet attempted the oil trick.
I get what you are saying that for optimum performance, tuning profiles is nice. But I’m not even talking optimal, I just want it to print halfway decently and that is not even close to what I’m getting. It’s hard for me to understand how printing PLA at 205C and 30mm/s (standard profile) can really be this disastrous.
And while I know all this makes me sound like a newb, I’ve operated some form of 3D printer for over 10 years and I’ve never had a problem like this. I feel like there is something seriously wrong with the SE 0.5 toolheads and I can’t figure out what it is. If anybody has more suggestions for me here, I’m all ears, but seriously stumped about how the filament grinding can be this bad.
