TPE Filaments
As a sort of small add-on to the excellent and comprehensive document about FDM polymers provided by Hyiger (thanks a lot BTW ) I’m writing my personal experience, so far, with a TPE filament.
Unlike TPU, there isn’t much availability online of TPE filaments. Anway, being rather tired of dealing moisture on TPU I decided to give TPE a try. One of the few well known brands making this stuff is Fillamentum. Two different hardness: Flexfill 90A and Flexfill 96A. Problem is that both seem to be always out of stock at Fillamentum’s own store and also at Filament2print. Therefore, I got the only other TPE that I could actually purchase : Recreus SEBS. It’s a TPE compound rated 90A hardness
My experience so far is very good in some aspects and not so good in others.
-Good :
This filament must be almost hydrophobic. Out of the bag (no pre-dry) it printed with zero stringing, on a pair with dry PLA. Surfaces came smooth and clean, far better than the bulky seams an noticeable layers that I get with TPU. Overhangs don’t drop at all. No problems entangling in the extruders gears or underextrusion after a seven hours print. My first settings were : nozzle temp 245C. Max. vol. speed : 5mm3/s. Cooling fan: 25 to 45% Bed temp: 50C (more on that below ).
-Not so good (or rather bad) :
Bed adhesion seems to be the opposite of TPU, which must be printed with a layer of releasing agent to prevent the model getting stuck to the plate. I found out that Recreus SEBS is very fussy in this matter. Adhesion to the satin plate with the bed at 50C (as with TPU ) is poor. Neither 3Dlac nor Nano Polymer worked well. After a few layers the model got loose from the bed. Using a garolite plate or kapton tape was even worse.
In the end I browsed the web of Recreus and there I found useful information, more complete then the brief data that you can download. Print on a smooth plate (probably a Cryogrip would be OK as well), bed at 75-80C, a LARGE brim, no glue. Print first layer very slowly ( 20mm/s ). With these setting I was able to complete a 7 hour print without issues. Even so, I noticed that the slightest blemish on the PEI surface is a potential problem. because the filament won’t stick there, so I got gaps and bumps in a small area of the first layer.
Fillamentum recommends using Magigoo PP as the best adhesive for their Flexfill TPE. I guess than a dedicated PP plate, like Prusa’s would be good too. As I haven’t Magigoo PP at hand, I couldn’t try it with Recreus SEBS.
RE: TPE Filaments
I bought a spool of eSun TPE-83A to make small belts and flexible parts. I just went to look for a link and it's gone from Amazon. The price seems to have doubled, so I don't know what to make of that.
It wasn't difficult to print, but it won't feed through the PTFE tube. You can push it easily, but it won't pull. I direct fed it into the Nextruder with little trouble. It strings a bit, but the big problem was adhesion. I used a satin plate and it stuck a bit too well. I ruined a part or two because they ripped when I pulled them off. A bit of alcohol and very careful removal was usually successful. The small belt I printed (for a cassette tape deck) worked well.
One characteristic of TPU and TPE that I don't like is even though they can be stretched by a large amount, they don't return to size. Rubber can do that too, but this is worse. If you stretch a belt beyond maybe 10%, it will be too loose, so you have to be careful.
Still, I recommend the stuff as another very useful thing in the toolbox.
RE: TPE Filaments
One characteristic of TPU and TPE that I don't like is even though they can be stretched by a large amount, they don't return to size. Rubber can do that too, but this is worse. If you stretch a belt beyond maybe 10%, it will be too loose, so you have to be careful.
PEBA is a good choice when you need "bounce". I've been using PEBA air from Siraya Tech for print shock-absorbing feet for printers, electronics etc.
As for these materials adhering too well to the plate, that's indeed a problem. I've found textured plates to work better in conjunction with a release layer. Magigoo works well for me. Also, one trick is to drip IPA around the perimeter. It will wick underneath the part and make it easier to remove.