Using TPU filament

How hard is it to print TPU compared to PLA. What changes are needed? Higher temps, speeds etc. I know that using it with a boden tube can be a challenge that can be mitigated to some degree.

As far as what type/brand to use. There is the basic 3DPC brand with good reviews but is on the low end. They also have some Sakata branded filament. Is it better? I have some Sakata PLA and it is very nice to use, is their TPU also good.

I need it to be a fairly flexible print.

P.S. has anyone printed it using the generic Cura profile?

Slow it down is the information you will see everywhere.

That is definitely accurate but it introduced a different problem that took me a while to figure out. I had problems with very inconsistent extrusion. I was getting a lot of sputtering and gaps in my layers. At first I thought it was wet filament that was popping so I dehydrated the rolls quite a bit which didn’t really help.

Long story short I figured out that I was printing too slow. Flexibles like to ooze out of the nozzle which combined with slow printing seemed to be causing the filament to almost cavitate in the hot end. Combine that with retraction and flexibles being like elastic bands that don’t compress or stretch with the same consistency as rigid filament and there was just not an even enough pressure on the molten filament in the hot end for it to extrude evenly.

I increased my print speed and reduced the retractions to get better results. Then comes the game of trying to balance print temperature with speed because if you crank up the temperature it lets the floppy filament move through easier but also causes more oozing.

I am using a micro swiss direct drive and hot end. If I increase my speed 5mm/s from where it is I have failures where the filament slips through the tiny gap between the extruder gears and the little section of Bowden tube. If I bump up my print temperature 5* I get uneven extrusion. If I change from a brass to a steel nozzle it effects the print temperature and results.

If you need softish flexible prints get some of the Filaflex 82a filament. I have gotten acceptable prints with it. I also use the cheap house brand tpu and have no complaints about it either. It is noticably more rigid though. I don’t use them interchangeably. If I need something with a bit of give that holds it’s shape I use tpu. If I need something soft I switch to Filaflex 82a. My standards of print quality goes down more the softer the filament is, I suggest you have tampered expectations of clean finishes.

Personally I used the ‘canned’ settings for generic TPU and really had no issues. That said I only have direct drive printers. I found it a bit stringy but not too bad. For my need I just burned them off rather than adjust and re print. It is a gasket I don’t need nice looking just working.

I have printed a lot of the flexible pla it isn’t as soft as it sounds like you need but it is gummy. Very ‘strong’ I have made wheels for a cart and they have held up really well.

Check out “lost in tech” on youtube. He has posted profiles for TPU on a Bowden tube printer.

What I need is something that is flexible but doesn’t need to be rubbery. Maybe Flexible PLA would be OK. Probably easier to print but I don’t know much about it.

It prints really easily. TPU for me at least often has blobs and stringy. The flex pla is clean. If it is think walled and dense infill it is very firm. If you lower the infill and as you start cutting perimeters it gets rubbery. A thin strip will easily bend to a circle. I use it for wheeels and it works really well over rough terrain. Not so soft they collapse but soft enough to take hits and not break.

That sounds more like it would fit my current needs. I assume it has a slower print speed but otherwise similar to regular PLA?

I’ve printed with TPE 87A, TPU 95A, and soft PLA on my MK3S+. Although the layers might look crappy in this pic, I can print faster with soft PLA over the rest. In different lighting the 0.2mm layers don’t look bad.
I sliced with PrusaSlicer so I cannot tell you what settings to use in Cura. Generally, in PrusaSlicer, I picked the “Flex” filament profile and all I tweaked was the temperatures and print speed via max volumetric speed for that specific filament. I think for the the TPE and TPU, those are set to 1.8 mm3/s. I did leave it at the default of 1.2mm3/s and dialed the speed to 120% on the LCD panel.
The TPE and soft PLA I have did not have shore durometer numbers and I see the soft PLA advertised on 3DPC doesn’t either. The black block is eSUN 95A which measures correctly against the durometer. The yellow is also TPU but unlabeled. It also measured 95A. The unlabeled gray PLA measured in at 95A as well. The unlabeled white TPE measured in at 85A which I am guessing is 87A.
I don’t get much blobs and maybe that is due to the lower temperature I am printing at? Soft PLA prints like regular PLA to me and is the easiest to use with similar bed adhesion. TPUs stick really well and you need to add glue as a releasing agent. TPE, or at least the roll I have, sticks to none of the beds I have. I tried various methods, including blue painter’s tape and finally landed on 3M packing tape. The closer your first layer to the tape, the harder it takes to remove it. Whatever your first layer is without the packing tape, with the tape, raise the first layer by about 0.08 ish or so and go from there.
I like the TPE for its flex, more elastic than the TPU and soft PLA. A little annoyance of having to use packing tape but it prints well for me.

The Pirelli tire was printed with the black and yellow TPU. It came out okay.

Soft PlA personally I print it exactly the same as regular PLA. I get really clean prints generally. TPU for me is often stringy and messy. I printed a bumper for a clothes line yesterday and managed to drop in off my deck 18 feet onto a aluminum bracket and it bounced and other than some grass it was fine. Very strong, very good layer adhesion. It does stick to PEI too well glue is needed to resist as mentioned.

Thanks a lot. I think I’m going to go with the soft PLA, it will probably do what I need.