Does anyone here have experience printing anything softer than 68A? If so, what was it and how successful was it?
For background to this question; I have a spool of 3D Meta (a local brand) “Support for PLA/PETG”. That worked acceptably using my AMS Lite when everything was stock standard. Now that I’ve made changes that resulted in a need for somewhat longer PTFE tubes (I’m using that star shaped stuff from Ali Express) the support material has become unacceptably problematic. If it doesn’t fail to feed it’ll likely as not to result in a clogged nozzle. So I decided to give up on it.
As I was walking out, with the intention of offering the spool to a neighbour, I noticed a little sticker inside the spool centre hole that read “TPU 68A”. I had no way of knowing if that was correct or just a “stray” sticker, and I wanted to print an item that required a softish material, I though to give it a go. Success!
This has made me wonder, just how soft can we go.
For anyone wondering, I have a spool holder that I made specifically for soft material. It’s so free-turning that I had to add a bit of a brake to stop it getting out of control.
Note: I had originally written 68D, when I should have written 68A. That has now been updated.
Let me put it this way: at a certain point, it gets so problematic that most people don’t want to put themselves through that trouble and just go straight for a mold, for example, for silicone or rubber. The advantage is that you can use it over and over again.
The softest TPU I’ve found for purchase is: TPU 55A - However, there are starting to be major problems with extrusion with these numbers, as the material is already extremely gum-like. There are special dual-gear extruders designed for this purpose.
Bambu, for example, already states at TPU 85A is actually not compatible with the A1 series.
Thanks for your comments and I can certainly understant what you’re saying. Nevertheless, there will be times where I have a need to produce or source some soft component. I would expect any such instance to be a one-off, so moulding would be undesirable, as the benefits would never be realised.
I’m going to edit the original question because I wrote 68D, whereas I shoould have written 68A.
At this point the question is merely one of curiosity. Prior to the experiment described in the first post I’ve only printed two items TPU items before, both using 95A. Neither worked out too well because 95A is just far too hard for the intended usage. At least I now know I can reprint them using the 68A, which has the flexibility I was originally hoping for.
Use foaming TPU. It softens after heating in the print head. I reliably print 60A RC tyres with it.
Sirayatech’s 85A does just fine in an A1, direct feed, no extruder tension mods. Works fine because they manufacture their filament very well, the filament is STRAIGHT. It is not that wild curly-hair looking junk you get off amazon/sunlu
Eponymous said it best, I would use foaming stuff if going any lower. Put on your patience pants and do the tests to get it working well.
I am trying to imagine what a pair of patience pants looks like and I am just giggling at what they could be… 
Now, that’s something to add to my notes. Thanks. I really don’t know if I will ever need to go down that far but not knowing the future it can be handy to be prepared for it.