SainSmart TPU Filament 1.75, Blck Flexible TPU 3D Printing Filament, 1.75 mm, 0.8 kg, Dimensional Accuracy +/- 0.05 mm

This stuff's pretty awesome. It prints well at 10mm/s through my (long) bowden extruder. Just make sure the area after the filament leaves the extruder gear is closely constrained so there's no gap for the flexy filament to buckle and push out when it's trying to feed.- 10mm/s- 220C- retraction disabled- cooling fan on after first layerI got the TPU in "clear", but it prints kinda milky. Colorwise, it almost looks foamy, but the surfaces are nice and smooth. In my experience it doesn't bridge very well and it can string, but neither is terrible. I recommend picking up some flush cutters to trim the strings; the prints are very durable, and so are the strings! You probably won't be able to cleanly pull them off and sometimes even a razor is tricky to use for cleanup.Layer adhesion is fantastic. Thin-walled prints stretch and squish pretty easily and return to their shape. I haven't seen any delamination yet.A single layer printed on the bed is floppy and droopy like wet paper. Two or three layers are about the stiffness of thick paper. Half a centimeter thick with 25% infill and it's a little less stiff than a rubber spatula. Add thickness and infill and the print starts to feel like a rubber doorstop.TPU is great for printing parts that need to friction-fit together since you don't have to worry about getting tolerances really close. Things will just flex into place.

This filament prints great in both direct drive (prusamk3) and bowden (Ender3). Ive printed about 5 or 6 rolls of the black with consistent results. BUT.... make sure the filament is dry. If it's wet, it will print bumpy and look like it's bubbling out of your nozzle. Even new sealed bags can have this problem. So I generally just dry it by default and the keep in a bag with LOTS of silica gel. I use an old food dehydrator at 122F (50C) for about 5 hours or more. I use a separate temperature controller to keep it at the temperature I set. That's important because higher temperatures can cause issues. Some dehydrators get way too hot. Keep this filament dry and you will be happy! Use glue stick on PEI to prevent it sticking too well.This is NOT super soft and squishy. It is called Semiflex. So keep that in mind. I use it for parts that need to be super flexible and durable. Parts printed with this are almost indestructible. You can't tear them or crack them.This is a good choice for your first flexible filament in most printers. 230C to 240C nozzle temps work well. Start at 230C and adjust as needed for good layer adhesion.

I ordered a roll of this TPU in Crystal Orange on Feb 13 2018. As it would turn out I ran out the last of it on Feb 13 2022. I bought it for the color, having seen some amazing prints others had done in this color. I also bought a roll of the crystal blue. I've used them randomly and for about every kind of project. This TPU prints as easily as anything you will ever print with. Extrudes smoothly and beautifully. It almost looks like its just falling out of the nozzle. It is VERY strong. Stronger than any TPE and as strong as any TPU I've used. So its great for protective thingys, but also nice to look at. The color is very dense and vivid yet is nonetheless very translucent. The color really pops under light, and looks even more amazing when its backlit. The filament itself seemed very consistent and never seemed to absorb much moisture nor did it discolor over time. And after exactly 4 years I can tell you that the last foot of the roll looked and extruded just as good as the first foot. So buy with confidence. This is some of the best stuff out there.

After a while of playing with PLA and PETG, I decided to take the plunge with flexible filaments. Starting off, do NOT try to print this without support between the extruder and the hot end. I figured that since this was not full on flexible filament, it may do just fine if I printed it really slow. Unfortunately the filament started to bunch up between the extruder and hot end. I stayed nearby, just in case, so I caught it before it became a major issue.After a little digging on the Robo forums, I discovered that a pen's ink tube could be used in a pinch. Some others suggested some small brass pipes, and others suggested PTFE tube. No matter which, I highly recommend having some method to fill the gap. I also printed quite slowly, and around 240C for the temperature.I printed a small vase, which came out pretty nice. It wasn't amazing visually, but it was cool to have something that could be squashed, and spring back. It also took quite a while to print, compared to some of the other items that I printed. Really, that is what I expected, so it isn't that big an issue. I also printed a gasket, which worked out quite nicely.Something you should keep in mind is that this is Semi-flex filament. This is not stretchy, it simply is flexible. Which definitely has its uses. It did just what I wanted it to do. After trying this out, I am looking forward to trying fully flexible filament.Why didn't I give 5 stars? Well, I can't say that I love this filament. I definitely like it, and will keep using it. If you are looking to try semi-flex, then I highly recommend getting this filament. I just don't currently plan to use it too much, since it is a bit of a hassle to use it right now. The ink tube works, but I would really like to upgrade my printer so that it can use this filament without any trouble.If you want to try it, then research ways to make it play nice with your printer. Well, unless you already have a printer that can use this already. Either way, if you can, I would recommend trying this filament.A little extra Info, I use a Robo 3D R1+. It can be made able to use this filament, it just requires minor modifications. If you find a more permanent solution, let me know. :-)

Very little stringing and zero bubbling (after drying of course).Transparent green looked great! Especially with a honeycomb infill, since it's semi visible through walls. Printed better than bambu or Polymaker tpu and is much cheaper.