Whats the softest TPU one can print with a X1 or A1?
Softness often causes more issue than its worth. Clogged extruder or just crappy print quality are risks as you go down the scale. The best method is to design your model to account for areas you want the flex and harden the bits that are structural. This can be by wall count, infill ratio/type, top/bottom layer count. It can be done in the design phase and then adjusted further in the slicer settings. As an example, do a single layer PLA/PETG flat print at .2 and see how flexible it is, risks of breakage/separation are there but you get the idea. TPU scales up and down ok, shore hardness just gives you another level and some reliability at either end.
I think you can achieve the softest part while still being printable by using Colorfabb VarioShore TPU. It is a rather stiff TPU which foams at higher temperatures and gets really soft then. You have to adjust the flow setting to account for the increased volume after foaming.
I have a roll sitting around here for months which I still haven’t tried, so I can’t give you first hand experience unfortunately.
If you see the steep price, don’t forget that you need less material for the same part due to the foaming and therefore reduced flow. I think at max foaming, it expands by 60%.
2 Likes
I’ve printed the VarioShore and as @Alex_vG states, the hot end temperature determines the softness or Durometer rating–To a point. It’s a bell curve so going too hot crystalizes the filament and the “softness” starts going back the other way.
You really have to slow the print down and adjust for the “foaming” action, but I got a Shore-A number of 59 in the solid area of a print according to my test stand. Fill type and amount will also play a role in the softness.
Oh, yeah, I printed with my normal .4mm hot end and had no problems with feed, jamming or clogged end. The next filament I used was PLA and the TPU was flushed just fine.
The stuff is pricey but if you have a need to print parts softer than the typical Shore-A 90 TPU filaments, the VarioShore is the way to go. Expect to burn some filament getting the settings tuned.
This chart from the VarioShore site shows how the temperature effect on the filament.
I have printed 95a kexcelled TPU, 95a Sunlu TPU and also a very soft Esun 83a TPE with no problems. I ran them all externally from a sunlu drier box with no issues and a 0,4 nozzle
I was printing inserts for RC car tyres and aftermarket steering wheels for RC controllers
Temp 226C-234C hot end
Bed 30C-40C
To help stop stringing
Avoid crossing walls ( on ) for what i was printing you may not need it
Volumetric speed limit set to 3.6mm
2.5mm retraction
1 Like