RE: TPU (Ninjatek Ninjaflex specifically) on the XL
First print today with FilaFlex 40. Like others I couldn’t get it through the side filament sensor. Even PLA, PETG etc needs quite a push to get it through.
Pushed an off cut of filament through the side sensor, disconnected the bowden tube from the tool head and fed the FilaFlex direct into the extruder and rigged the spool to above the printer.
Printed just fine after that.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Hello. I’m printing a material similar to Ninja Flex (also 85A) and the print is starting off well. But after a few layers, the printer starts to under extrude until I start to manually push in the filament by hand. This is happening (I think) because the filament is not flowing. It is just stretching. I have already skipped the first filament sensor. Any suggestions?
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Are you getting filament wrapped around the extruder gear? if you are you're printing too fast and/or with not high enough temp.
Since your filament is similar shore hardness to ninjaflex you can start with that profile.
Things to consider in decreasing order.
You already mentioned this, but just for completeness, skip the filament sensors on the side.
Check the temperature range of the spool. Ninjaflex profile prints at 237 which is right in the middle of the range for the material
Check your filament MVS. the 3.5 default in the ninjaflex profile is too fast. I print it at 1.25(which is super slow, but it's reliable)
Check your retraction length. Set it to 1.5. The default leave some gaps in the surfaces of the printed object.
Check retraction speed. the default is 60ms, which can cause jams. I set to 10 or 20mm max. The rational is that quick retractions with flexible filament can cause the filament to bunch up in the extruder. Coupled with the previous point, the more and faster you retract is invitation for a jam in the extruder.
Check how tight your idler is set. The default idler tension(my unit was assembled) was really tight. I loosened the idler bolts a bit on my extruders.
I think that about covers it. TPU takes an enormous amount of patience to get dialed in.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
I'm using Overture High Speed TPU filament (95A). It works well with my dual head printing (PETG + HS TPU) under the following setting.
- Firmware 6.0.0-alpha with Phase Stepping enabled. Nozzle 0.4mm.
- Loosen idler tensioner screws - turn them for exactly 2 turns, as per the manual. (YouTube video)
- Use the PrusaSlicer (2.7.2) built-in Amazon Basic TPU profile. It works as-is just fine. Usually I enable "avoid crossing perimeter - 9999%". That's it.
Idler tensioner screw was the most critical part to me. Before this, filament gets jammed badly. After this, no jam anymore!
To turn them exactly 2 turns, I marked on those screw head with a permanent marker, so that I can see it clearly.
RE: TPU (Ninjatek Ninjaflex specifically) on the XL
Here is my Prusa XL filament loader (mainly for flexible TPU), using an electric screwdriver. Model on printables:
https://www.printables.com/model/978873-prusa-xl-fast-filament-ptfe-tube-loader-incl-tpu
Video: