Consistent Jams With Chube
I have been getting jams in the heatbreak of my conduction chube for a while. They can currently be reproduced consistently under the following circumstances:
- An entire print completes with PETG. The next time filament is extruded, it will be jammed.
- PETG is unloaded. If I load PETG, take it to temperature, (optionally) extrude some, and let it cool down, it will not jam.
- PLA is brought to 150 C. This is the least tested option, but it does mean that PLA cannot begin a successful print as it will jam before the prime blob even begins. PLA also seems to jam by the time of unloading. Unsure if this is the act of unloading or something prior.
- I have not tested ABS / ASA with this hot end.
This is a conduction chube with an LGX Pro and the LGX CHAMP adaptor.
Possible issues:
- Wrong PTFE tubing? The jam on unload was noticed before swapping to a PTFE tube with a larger ID. There were a few instances where the tube was not set properly, but that was not always the case. I do not believe this to be the issue. This refers to the PTFE tubing between the extruder and the hotend.
- Not enough cooling? Most of these were using the passive cooling of the CHAMP adapter. Some were tested with a 40mm fan mounted. No change was noticed.
- Wrong Temperatures? The PETG was printed at 230. The PLA was supposed to be printed at 220, but jams can be found at 200 and possibly 150. I am going to double test that jams happen at 150 after sending this post (because I need to take off the nozzle and unjam it to test.)
- Insufficient thermal paste? Untested. It is possible that needing to remove and replace the chube from the mount so often has removed too much thermal paste from where the heatbreak meets the heatsink. I have little thermal paste on hand, so I would rather eliminate other options before testing this one more.
49 Replies
Are you chamfering the OD or ID of the PTFE tube? Do you feel squish on the tube when mounting?
I did not chamfer this one
And there wasnt much squish with this tube length. Some past ones did and resulted in part of the tube bulging out
How you talked to Luke about it?
Not yet
Hm, the answer might be as simple as heat creep.
Just now:
- set it to 230C
- manually loaded some PETG
- told it to extrude a few times. Zero issue
- left it at temperature for a moment while I went to go find the printer config option to set the nozzle size
- told it to extrude again, jam.
After it cools down and I can disassemble it to clear, I will try the fan on the heatsink again
You for sure need the fan.
depends on the version he has, the conduction version doesn't need a fan (it is passively cooled)
Just sayin may not be enough surface area without
It is conduction, yea. Attached with one of these
https://lukeslabonline.com/products/chube-lgx-champ
Which indeed doesn't technically need a fan, but does have the screw holes for a 40XX fan. And those aren't too costly to add (in terms of weight, wiring, complexity, etc)
I tried a fan for one case, but only one case. It would be worth it for me to more thoroughly re check (because when I understood the problem less, I had to remove the plate holding the fan every time I fixed a jam. But that is no longer the case)
I can also test the fan plus reapplying thermal paste between the heatbreak and the heat sink. It's possible that without the paste, fan or not makes no difference
I have to cool my lgx more than I do the conduction itself
That is fascinating and would mean I've been looking in the wrong direction
Because after some prints and some tests, the motor is indeed hot. But I assumed that was because of the 250C heating element less than 2 inches away
so: I print abs in a 70c-ish chamber across multiple printers
they all jam in the gears, not the hotend
like i can't touch my gears but i can touch the plate the hotend is mounted to
so i added a fan to cool the motor and the extruder casing
and boom, problems solved
On the CHAMP or on the back of the LGX motor?
But that does seem consistent with what I've noticed, even if I didn't connect the dots
Like after turning off the heater and waiting for it to cool, but not turning off the extruder motor. The motor would still be hotter than the champ plate
I have not tried touching the champ plate while the heater was on and at temperature because I do value my fingertips
Champ
Both work that way. Air is actually better at it
22cm^2 more contact area
one is CALLED the conduction version
So? Doesmt matter with their capabilities. Im a beta chube user + Ive done integration cad for chube. I know this topic well
Air is quite literally better for conduction purposes. I gave u a number above for cm^2
so, I am not saying one is better than the other. I was trying to ask the OP which version they had
Champs designed for conduction only pretty sure since the chalice seat distance
depends on the version he has, the conduction version doesn't need a fan (it is passively cooled)I was telling u both can be passive
So the fan did solve the ambient pla jams when idling at 150C, but not the jam after a print
BUT I may have found what is leading to that issue now,
I have a Bondtech LGX Pro. The RatOS configurator only has an option for an LGX not-pro
and looking in RatOS/extruders/lgx.cfg
the quick start guide for the LGX pro claims a rotation distance of 7.805 (and a #gear_ratio of 0 but I dont see that listed anywhere)
and comparing the technical sheets of the PRO and the not-pro,
PRO: MAX Peak Current 1.5A Recommended current 700-1000mA
not-pro: MAX Peak Current 1.0A Recommended current 450-600mA
i dont know that any one of these could be the issue, BUT
how do I know that the retract in the end print macro is correct now
where does
end_print_retract_filament live
e: in RatOS/macros/util.cfg
variable_end_print_retract_filament: 10 # float = total amount of retraction in mm after a print ends
why is it 10
what's it supposed to betbvh
i never retract after a print more than 3mm
use the lower current values.
So I didnt touch the current values, and didn't actually change the rotation distance (had it set twice in printer cfg)
But I did run an update all and now it does this
Turns freely by hand when off
e: I dont think anything in any of the updates broke it
e2: oh yeah ratos saves all the printer cfgs so i can narrow down the change
This should be a video with sound
im fuckin dumb it was a loose wire
HMM
I got a new crimper in the mail just today lol
hm, it's less consistent but still seems to be happening with pla. this time got through two test prints, paused to check resonance stuff, and the third jammed right out the gates
going to try some abs
e: actually i still need to try lowering the temp on the pla
U tried putting a fan on the lgx motor?
pretty sure @Luke's Laboratory is doing that now.
not yet. I'm dialing some stuff in but somehow having the best ABS prints of my life lol
so i'm gonna replace the hotend parts while its going good
"somehow" its because of the very long meltzone and thermistor being on the nozzle end so i can actually print at the temp i think i'm printing at
That sounds like ptfe shenanigans
It might be a PTFE issue. There's a slight gap between the champ and the lgx pro that I first noticed after re-assembling the motor from when the wire was wrong.
It's possible something didnt line up when I put it all together, and it's possible the tube is a tiny bit too long.
I next plan to try simply lower pla temps to see if that fixes it. And if it doesn't, I'll have plenty of chances to take it apart and check
Is the exact PTFE tube length known? It's kind of guess and check for me
I may have found the cause of the apparent PTFE issues,
Without the CHAMP, I can mount the 4010 fan in place with the four screw holes on the LGX pro
(Top left screw sticks out because I didn't have the right size in arms reach)
If I use the top screws in the champ through the back to the motor, there is a gap with no wiggle room
If I use the bottom holes through the champ to the motor, there is a gap with wiggle room. It can be brought flush with pressure but will not stay flush
If I push the champ flush and shine a light through the holes to the back, there is not a circular path
These fit tests were all done without a PTFE tube in place to make sure nothing was getting in the way
But:
I do not think it is possible to mount the champ with more than the two bottom screws.
It is not possible to mount a 4010 fan to all four holes all the way through
I do not know how to mount the champ in a way that keeps it flush without also using the side holes
uh, the top holes should not be used with the lgx body
the top two holes are for the fan
the bottom two holes in the champ are to mount the heatsink to the lgx body
So the bottom screws do not go through the fan to the champ to the motor
OH i may have figured it out
I was still getting play when i attached the CHAMP using just the bottom screws, until I switched to screws with larger heads
Can barely see it,
But the upper ones let it wiggle and the lower doesn't
BUT the lower is also shorter and barely engages with the threads on the other side
no, they certainly do not
i appreciate you bringing up this to us tho, we'll make better content
to expalin the assembly
Glad I could help at least!
And later tonight I get to check if it's actually all working now
I think it is fixed with one possible caveat, and I'll sum up the entire fix and the process after I confirm it works but that caveat:
One of the issues was that the heat from the motor was enough to soften PLA. Thus, the heat sink fan was for the motor heat more than the hot end heat creep.
BUT if there exists a situation where the hot end is below 50C and not active, the fan will be off. Thus, there can be a situation where the motor is energized and not cooled. This can cause the PLA to soften enough to misshape and jam on the next print. Such a situation can arise if the sample spread is too large during beacon probing and the print is cancelled.
Active cooling on the motor itself (ie, a second fan) likely wouldn't fix this because it would be keyed into the same state. But I wonder if a passive aluminum heatsink on the motor would help. I do need to redesign the wire support on my toolhead, there's an opportunity to do both at once.
also i would like to note that this just happened as I was typing this lmao
Add something like this to keep the toolhead fan on longer
I think that would help alleviate the problem, but not fix it entirely. It might be a matter of simply not letting the motor idle when pla is loaded
like at some point there is a level of "user error"
I have pla sometimes melt in the gears of non-Champ lgx
Happened on the giga earlier this week
its so wild that it can do that on it's own
i'm def gonna look into a passive heatsink for it then
Just have ur fan on more
But overall: I'm going to push my luck later and try pla at 220C because the volumetric flow rate of 69 mm3/s is very nice,
and try something large
but i do think i've solved most of the blocking issues. (not counting stuff like the toolhead parts that need tightening up for better wire managment, better ducts etc etc.)
Using an 06 nozzle and not my prettiest filament,
Letting it print then fully cool down without touching to maximize the chance of failure,
Four successful in a row
It's a 4010 fan, already on max speed when its on
e: but also i will be setting it to trigger on 35C, yea
yea thats what i meant by "more" 😄