TPU not working - K8800


Today I tested NinjaFlex TPU on my K8800.
First it was a lot of problem to feed the filament into the extruder. After a while I was lucky and could load filament from the menu display. I chose Load TPU from the menu and it started the load procedure. After some strange noice, the old filament became visible, but the TPU filament did not turn out. OK, I then started to print a model with TPU settings but nothing came out from the nozzle. It is very bad that you cannot extrude filament from the nozzle without printing. I had to give up and try my Cetus3D which I succeeded with.
Conclusion: K8800 has a bulky extruder than cannot feed soft filament.
K8800 does not have the possibility to feed filament without printing, good in this situations.
And finally it should be possible to adjust the idler pulleys, easy from the top with a screw.


Yes, this is a known limitation of any 3D printer with a Bowden extruder. Flexible filaments cannot easily be “pushed” down a long tube to the extruder. This is a design trade-off that (on the K8800) reduces the moving mass of the print head in order to reduce vibration and allow faster printing.

Your Cetus3D has a direct drive that is more suitable for use with flexible filament.


@uffe53puffe have you tried @Psycho’s extruder upgrade?

Why did you start this thread in ‘Vertex 3D Printer’ which is I think for K8400 and not in Vertex Delta which is for K8800?


@uffe53puffe There’s many upgrades available here: