COREOne TPU Fun - Random Filament Change?
New COREOne owner here - Figured out a possible workflow to load TPU (Creality TPU-95A using the generic FLEX filament template) and the prints come out ok. But sometimes a print will pause and prompt for a filament change (unload existing and walk through the reload). After multiple attempts with the same print, I can confirm it happens randomly. What would cause this?
My guess is the extruder detects some kind of change in the filament during prints. When it finishes trying to unload, the TPU feels slightly stuck but eventually pulls free. When I open the idler to (re)load the TPU there’s often a piece of TPU in the filament hole of the heat sink. I’m wondering if the extruder can tell the filament isn’t moving or if it is breaking or something. I will admit that I did NOT loosen the idler nut to reduce idler pressure on the filament … because it seemed I didn’t have to. But maybe that’s part of the problem and loosening the nut would help.
Note to
RE:
I didn't have any particular issues with TPU-95A and a stock Core One. I've been printing a lot of softer TPU and in order to do so I had to install a bogie and filament sensor mods.
You can find them here:
https://www.printables.com/@hyiger_2009121/collections/2834525
RE: COREOne TPU Fun - Random Filament Change?
I'd suggest loosening the extruder gears exactly a full turn and try again.If that works, nice. If not, you can tighten it a full turn without changing things for PLA etc.
Strange bug though.. For me, I simply pushed the flow rate too far, the 95A TPU wasn't stiff enough and bent sideways.The extruder kept working and when I noticed and aborted the print, I found about 20 cm of the TPU filament string inside the idler, pushed into every empty pocket, wound multiple times around the extruder gears etc., lol.
I couldn't unload or anything and hat to roll the spool backwards until the filament string was tight again.
No idea, why one of the two filament sensors would stop detecting filament though...
RE: COREOne TPU Fun - Random Filament Change?
Thanks. I’ll check out the bogie
RE: COREOne TPU Fun - Random Filament Change?
yeah, that sounds similar to what was happening to me. But to clarify - the filament sensors are both detecting the filament ok … they show ON. What’s confusing me is why the print suddenly stops and say it’s changing filament. I’m wondering if maybe the filament is breaking and the sensors can tell that the filament isn’t moving any more or maybe detecting the break itself. Either way, it attempts a retraction.
I opened the idler and can confirm that the filament is broken when I get the prompt to change filament … I just can’t tell if it broke first and then prompted to change the filament (makes sense) or if it’s breaking on retraction after it prompts to change the filament, because the broken ends are still connected by a tiny string of melted filament, as if it was pulled apart.
I loosened the idle nut and that seemed to help … it printed for a long time before the issue reoccurred. And it also reloaded the filament correctly.
I saw the One+ printable upgrades and the notes that say they help with softer filament … I may try those.