Hi there
Having an issue with kexcelled 64d tpu for ams.
Its like the first layer isn’t going down nicely despite me doing both calibrations (of which look pretty awful!)
Using bambu tpu ams as my base line.
The filament is what I suspect to be properly dry.
Does anyone have any ideas please!
Essentially the first layer goes down bad and then the next layer just destroys it and picks it all up
Thank you in advance!
You need to clean your build plate. Hot water, dish soap, nylon scrub brush, dry with clean paper towel afterward.
You should also use glue as TPU typically sticks TOO well to PEI build plates, you need it there as a release layer.
A PLA raft also does a great job at this. I usually prefer that a little more.
…
You need to clean your plate better.
But I also see underextrusion. Try a few cold pulls, then calibrate your filament.
Cheers guys I will have a clean of the bed but not so sure it’s that as it looks like under extrusion?
Despite me calibrating the filament though which is weird right?
Disclaimer… I only ever run TPU direct feed into my extruder on my P1s, so I don’t have experience with TPU for AMS.
With that out of the way… besides the spots where the TPU isn’t sticking, it looks like the under-extrusion is occurring to the front and right of the model… might suggest that the movement of the head is causing the filament to get stretched, causing a reverse direction force, and the extrude gear can’t compensate.
What happens if you move the model more towards the back of the plate?
My first thought looking at your images, was that PA was not properly calibrated because the extrusion looks very different (much better) at the edges.
Hearing from you that the flow rate was too high makes perfectly sense now.
Keep in mind that 64D is quite a bit softer than the 68D that the TPU for AMS from Bambu is.
Did you start of with the Bambu profile, or did it come from the filament manufacturer?
Underextrusion on layer 1 might also be ok extrusion but imperfect z offset, from a photo it’s not easy to discern. I would worry more about cleaning the plate and ensuring the filament is dry - ooze could be making some of those artifacts that then get pulled up on the next pass. Hot soapy water. Non food brush. Clean towel to dry, etc.
You don’t need glue - isopropyl alcohol works amazing as a TPU release agent
