3DPrinting

I don't print TPU on a textured bed. I use the flat side of my build plate, which I also have coated with a giant sheet of Kapton/polyamide tape. Peeling the completed parts off of the smooth surface has never been an issue.

A word to the wise: Always run with a sheet of polyamide tape if you have a flat build plate. This will go a long way towards protecting the finish and flatness of your plate, and I have definitely saved myself a couple of times when having a Z offset that was too low and thusly crashing the nozzle only into the tape and not the surface of the expensive plate itself. You can apply adhesive and clean the tape's surface just the same as the PEI surface of your plate, but once it gets worn out or chewed up or otherwise no longer produces parts with a pretty underside, you can just peel it off and reapply. If you've already fucked up the surface on your plate you can also paper over this with a layer of tape which will smooth out small scratches, pock marks, and other imperfections.

And if you really need to employ the nuclear option to get a stuck part off of your bed (i.e. if you've printed something with a sticky filament such as TPU or PETG and happened to have your Z offset way too low) you can peel the tape off along with the part. The tape is unlikely to survive this process, but a pack of 12 sheets is only $20 or so.

In my experience, TPU benefits from a higher first layer - it prefers being just "deposited" by the nozzle instead of slightly squished like for PLA and PETG. You can try raising your Z adjustment by 0.02 - 0.05mm and see if that makes it easier to remove.

If you work with transparent TPU and don't want it to turn white, print slow and cold.

Never tried it myself, but "functional print Friday" channel on YouTube uses IPA after printing with slow steady prying to remove stuck tpu. The IPA wicks under the print and releases it.

Turn off the heat on the hotbed. TPU doesn't need it, and it makes removal much easier if you don't heat the hotbed.

Also reduces the amount the printer heats your room by 90% or so.

Smooth prusa powder coated works great.

Drying makes a gigantic difference. It only takes around an hour in the open before TPU changes significantly from any ambient moisture and become visible in the print.

If you can control the moisture to a minor degree, you can alter the mechanical properties significantly. Once you hear popping, you'll likely start blowing holes in prints, but there is a stage before this where the bubbles of gases are present but are not coalescing into the larger audible voids of escaping steam. You will see this on long prints using dried TPU filament left out in the open. There will be a much tougher start to the print that gradually degrades into a slightly softer and more flexible texture. It will likely turn slightly foam-like spongy rubbery soft for a section and then it will start popping and dropping walls with holes in the structure.

If you write down the room temperature and humidity and note the time it takes to get to this moisture property, it becomes possible to alter the flexible properties or empirical hardness of a TPU to make it behave in off label ways. This is essentially creating your own rudimentary foaming or light weight filament. It works best for vase mode or other small single wall structures. I have used this based on intuition alone. I imagine with a bit of record keeping one could control the humidity of a box to do longer prints within this state of foaming softness. I don't know of anyone using a humidifier like the ones for acoustic guitar cases or cigars in a filament box, but that would be an interesting thing to play with too.

I've never had too much trouble removing TPU from a textured PEI plate. If the part doesn't want to come off, lift up a corner of the part with a knife and put a drop of IPA under it.

I use a bit of glue and try to remove it when it's still warm but not hot. Zero issues so far.

I've got a textured PEI bed and when I've printed TPU, the adhesion has been perfect, i.e. good enough that the part wasn't going to go anywhere unless I wanted it to, but still easy enough to remove when the print was done and the bed had cooled. I guess it could vary from filament brand to brand, so it's possibly worth trying the same brand as I used, which was cheap Geeetech stuff. It's £8 a roll, and I've used their cheap PLA for ages. I wouldn't recommend their ABS+, though, as it seems to break down at the lowest temperature that gives reasonable layer adhesion.

I just use my textured sheet and remove very carefully - but I tend to use harder TPUs which makes flexing the sheet more effective.

I have heard people say that TPU is the reason they still keep a glue stick handy and the Prusa material matrix says to use it on their smooth PEI sheet. And it suggests a polypropylene sheet is also applicable without glue stick.

I've read that PEI makes TPU much more difficult, and switched out my PEI plate to my plain glass plate because of the horror stories. I just rattled off some TPU last night using glass and a single pass of a PVA glue stick, and it was super easy to get on and off the plate. Like if PETG was a bit stickier.

I've had success printing TPU onto the uncoated steel side of a print bed. Flip it over and clean it, gently sand it if it's too smooth for the first layer to grip.

I used to throw the textured pei plate with the sticking print into the freezer for 15 min, made removal much easier. Now I just add baby powder onto my build plate, and remove the print at room temp. Much easier, a little messier

Not sure if I've ever tried without it, but I cover the standard textured mat with blue painter tape for printing 95A TPU on an Ender 3 Pro. It sticks just fine for printing and haven't had any issues removing the print after.