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