TPU with the XL Enclosure?
Has anyone been successful printing TPU with the XL Enclosure? Since adding the enclosure, I can't figure out a pathway to run the TPU where it doesn't bind. I was bypassing the side filament sensor and running a PTFE tube directly from my dryer to the print head before the enclosure. Since adding it, there are too many sharp turns given the openings available and the TPU keeps binding, leading to under extrusions and then clogs.
Any ideas?
RE: TPU with the XL Enclosure?
Maybe try this: https://www.printables.com/model/718498-prusa-xl-soft-tpu-cable-clip-to-extruder-prusa-xl
This reduces the frinction on the long path but still guides the filament. You can install it parallel to the existing main tube.
RE: TPU with the XL Enclosure?
Experimented some more. It looks like the under extrusion problem is more because of the filament getting jammed up in the gear than it is problems with the path. I simplified the path and made sure all retractions were turned off. Five minutes into the print I had an under extrusion, and when I checked it the filament had become wrapped in the extrusion gear.
I didn't have problems with TPU before adding the enclosure. In that process, I updated the PETG parts to CF parts. Other materials print fine after the upgrade, but I'm having a devil of a time with TPU.
I am using the hardened steel nozzle, although I think I was using that before the upgrade, too.
What further trouble-shooting recommendations do you recommend? It's frustrating that settings I used before the upgrade no longer work.
RE: TPU with the XL Enclosure?
Which hardness grade is that TPU ?. It isn’t the same a relatively hard TPU (95-98A) than a very soft one ( 70A or less ).
Anyway, I don’t own a XL, so l’m not familiar with the Nextruder, but if the gears are in direct contact with the stepper shaft, they can get quite hot after a while, more so inside an enclosure. This is a recipe for trouble with soft filaments.
Some extruders have secondary gears made from plastic ( POM usually) between the main gear of the stepper and the gears pulling the filament. This intermediate plastic part serves as an isolator, so the stepper heat isn’t transmitted to the filament. That’s very useful for soft materials like TPU, but also for PLA.
RE: TPU with the XL Enclosure?
Have you tried it again, leaving the enclosure open?
RE: TPU with the XL Enclosure?
Yes, I have not closed the enclosure during testing
Have you tried it again, leaving the enclosure open?
RE: TPU with the XL Enclosure?
Thanks for your response, but none of what you suggest applies to the Nextruder.
Which hardness grade is that TPU ?. It isn’t the same a relatively hard TPU (95-98A) than a very soft one ( 70A or less ).
Anyway, I don’t own a XL, so l’m not familiar with the Nextruder, but if the gears are in direct contact with the stepper shaft, they can get quite hot after a while, more so inside an enclosure. This is a recipe for trouble with soft filaments.
Some extruders have secondary gears made from plastic ( POM usually) between the main gear of the stepper and the gears pulling the filament. This intermediate plastic part serves as an isolator, so the stepper heat isn’t transmitted to the filament. That’s very useful for soft materials like TPU, but also for PLA.
RE: TPU with the XL Enclosure?
Where are your idler-screws are set? Standard would be that the screw tips reach the front face of the idler nut. If they are set differently, set them as they should be and try again. If they are set right, try loosening the idler-screws for about two turns and try again. If needed repeat.
You'll find out, when it absolutely lost grip because the idler flops around. 😅
RE: TPU with the XL Enclosure?
It's been a while since I got back to printing TPU. Still having trouble. Loosened the idler screws, and the filament wouldn't feed at all, so I tightened them. I also tried to increase flow by heating up by 5 degrees, and I eliminated all retraction. No matter what, I'm still getting jams. I've even tried a second head.
The TPU loads and purges correctly. I get a good first layer. About the third layer, the extrusion gets thinner, and when I stop the print I can see that the TPU bunched up at the bottom of the wheel, looped, and was drawn under the wheel. I have cleaned everything as best I can (I did find a stray piece of cleaning filament jammed into the wheel/gear assembly and thought that was my problem, but the problem persisted in subsequent tries after I cleared it). Am using Ninjatek Ninjaflex, so it's very soft. There's almost zero resistance in my filament path.
RE: TPU with the XL Enclosure?
Yes I've been printing out without issue. 95A. Prints directly from my drybox. I am bypassing the side sensors, and have switched out to 3mm id tubing from the stock 2mm id tubing.
Getting wrapped around the extruder is from trying to print to fast most likely.
Surprisingly it prints better hot with lower retractions. I think due to the soft nature of the filament if you get crazy with retractions you'll get jams because the filament will act like a spring in the nozzle. I'm not home to look at my profile, but I took one of the default profiles for 95A TPU and tweaked it. You also have to print slow. I think I've got the volumetric flow rate at like 4, printing at 230 nozzle temp.
You can definitely do it, but I did have to do a fair bit of profile tweaking because I was not happy unless it was printing perfect. I do a bunch of parts with TPU printed directly on PETG, so I insist that the TPU looks as good as the PETG, and that's a tall order.
Good luck.
RE: TPU with the XL Enclosure?
Oh this is so frustrating. I dialed the MVS back to 1.2 and got a good print, but then the filament jammed. I had gone back to default retractions that Prusa recommends, and I turned those way down, thinking that the retraction is causing the bunching up beneath the wheel. Still jamming. So I thought I might be getting heat creep now that I'm printing much slower, so I turned the temps down to between 228 and 233. Problem got worse, not better.
I wish I was at a stage where I was fine tuning print quality, but I'm stuck just trying to get the TPU to feed. I didn't have any of these problems before the enclosure installation. So frustrating.
RE: TPU with the XL Enclosure?
Oh this is so frustrating. I dialed the MVS back to 1.2 and got a good print, but then the filament jammed. I had gone back to default retractions that Prusa recommends, and I turned those way down, thinking that the retraction is causing the bunching up beneath the wheel. Still jamming. So I thought I might be getting heat creep now that I'm printing much slower, so I turned the temps down to between 228 and 233. Problem got worse, not better.
I wish I was at a stage where I was fine tuning print quality, but I'm stuck just trying to get the TPU to feed. I didn't have any of these problems before the enclosure installation. So frustrating.
I'll screenshot my settings later.
What TPU hardness are you running?