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The biggest problem printing with TPU for me has been getting proper layer adhesion along the XY axis. Maybe I need to adjust line width, but for whatever reason the TPU bonds well along the vertical axis but not the horizontal. Any suggestions?
Hello stefan, Thank you for the nice and insightful video! I have a couple of suggestions to test based on my experience with TPE filaments: Temperature greatly changes stiffness of TPU. I have printed powepads for my EUC. at -20°c they shattered instantly from small impact. It was printed from purple transparent TPU from esun which gets to my second point/question: Does transparency or colour affect material properties? I also have parts printed from extrudr medium anthracite (grey), it still holds up fine. I have also noticed creeping issues with TPU. Even under small load they will slowly give up and permanently change form. I have noticed this from several different applications, biggest one was kickstand for EUC which made it unusable because it gave up on one side and will always flip to that side. It worked fine for couple of days until it started to give in. I printed thin PETG supports to fix that issue. That brings my fourth thought, would heat treatment (annealing)help with this issue, or are there TPU filaments that doesn't do that. (It also happens with PLA, you cannot print springs or compliant mechanism that are stored as momentarily "deformed state". It will slowly give in. Also side note: I have noticed PP, to have a considerable amount of friction compared to it's shore hardness. It is also really nice material.
I printed some inserts for a tablet holder from TPU. It was as easy as you said (bed adhesion is amazing - the brim I added was completely unnecessary) and I was blown away by the seemingly indestructible parts I got. However, they're not as soft as I had hoped. Most generic TPUs you can buy are 95A shore hardness, which is just too hard for the "rubbery" effect I was going for. I want to try 30D next. Overall an excellent video, the only thing I think not mentioned was price - unfortunately, TPEs are all quite expensive, with the softer ones easily going into the 80€/kg range.
One thing while printing flexible materials i learned the hard way is to also lower your non-print speeds when printing tall models. Bed slingers tend to cause quite a bit of wobbling and models can get misaligned
@@timgromeyer2061 No idea, sorry. I would assume that since with delta or corexy the model itself doesn't move in x or y direction the movement speed shouldn't matter. I mainly use bed slinger for my printing and this is the first time i encountered this sort of problem with any filament. I admit i was also bit greedy and wanted to cheap out on structure and some of the supports and adding some more mass to model made it a lot more stable.
The issue with bed slingers is not speed but acceleration. So you can keep print speed on "bed-axis" but drastically decrease acceleration. You could also reduce acceleration by height, so the total print time is even lower
4:22 "I can't really wrap my head around what to print with this" Oh I think you already know, judging by what's printing in the background. I'm sure Mrs. Stefan is quite pleased.
Someone in the Rat Rig Facebook group gave me great advice that really works: When the print finishes rather than tear it off the bed pour a little bit of isopropyl alcohol or similar around its edges. I had trouble with phone cases that kept getting deformed when pulled off the bed. This solved it completely. The alcohol gets under the print I think via some capilarry action and almost releases the print from the bed. The force needed to peel it off the bed is reduced to something that feels like 10% of what it was before. I have tried it with several TPUs that before tended to damage my powder coated PEI sheet and it works beautifully. With G10 smooth surface it works too but a bit slower. After getting it off the bed this way I just have to let it dry out the alcohol from its pores.
@@MartianMoon All my beds are flexible too, but especiall with relatively low height parts with big foorprint the printed part is sometimes more flexible than the bed 🙂. I buy the IPA in plastic bottle with a tiny opening on top so it is easy to squirt a thin stream of it around the base of the print too.
@BaghaShams for textured PEI and G10 I know for sure it does. I never use glue stick. I am guessing that for smooth PEI it works also without gluestick but I don't have one to test it.
My favorite use for TPE is printing gaskets, though I'd really like some purpose-built ultra-soft filament with excellent chemical resistance specifically designed for it.
Prusa has a table with many materials and brands on their site that is really simple and intuitive. I’ve used it a couple of times to check the best brand and material for some of my projects :)
I legit allways use TPU when possible. It is basically indesctrucable ! And The Layer adhesion is sooo good. I have 2 Waterbottle holders for my bike printed in TPU, every other material cracked after a while cause of the impacts of the full waterbottle but the tpu one still works just fine!!
Can you recommend some very hard TPE ? I have some TPU over here but it's very soft and hard to print on my ender 3 with Bowden drive. I don't know the shore hardness. I don't even know the brand.
@@Saeschboy You can just buy hard TPU, most is quite flexible, but some sell multiple varieties, including hard ones. Basically indestructable to hard forces.
@@tarakivu8861It's a shame the hard TPUs are so expensive though. Anything above 95A is ridiculous. There is 64D and 74D hardness TPU available which sounds incredibly useful but it's like $1 per gram.
I actually slightly oil the bed for TPU: Put a drop on the PEI and distribute it. Then wipe it off with a dry cloth. Works great for me. (I use some fine mechanics oil.)
... and Every Bourbon is a whiskey, but definitely not every whiskey is a bourbon! The maximum volumetric speed was one of the best discoveries that I've made in 4 years of printing.
17:54 That moment of inertia formula that you used, works for rigid bodies. For a pipe it's only relevant for determining its resistance to buckling, but for comparing the overall stiffness of the pipe you'd want to use a formula where you take the area times the distance to the centroid axis.
The current best use for TPU for me personally has been airsoft and cosplay, TPU is fantastic for Absorbing BB's in armor. And the flexability make it super nice to wear aswell
The flexible filaments can be used to print replacement covers for electronic equipment. For examples, the little "hatches" on cameras that cover the HDMI, phone, mic... plugs. These parts are often not available (especially with older cameras) and so worth printing.
So much information-and work to get this all together for us in a highly organized package. You're the best! (Aside: I've had the Recreus 60A for I think two ears now and I still haven’t decided what to print with it!)
Even through a bowden tube I find myself using more retraction than is ever recommend for tpu. I like to use the purple glue stick because of the PVA in it. Drying the filament makes the biggest difference! Another really good TPU is the Ninjatek Armadillo. It's tough as shit, and you can print it faster. It has great industrial applications, and I feel it's being slept on.
I have a small home based business that 3D prints TPU products, so I appreciated this flexible filament video. I'm an engineer so I always like Stefan's data driven approach. I know from past CNC Kitchen videos that I can't get most of these filaments in the US but I appreciate the links to the filaments. I need a more energy absorbing material for a product that hasn't been converted to 3D printing and I need to try the foaming TPU but it's never in stock.
Used TPU to 3D print a door stop. I was looking at all the poor designs and lamenting spending $5 to $10 on crappy commercial one made of rubber that I had already seen fail. So I designed and printed some. The other benefit is that it can be easily modified for larger gaps or heavier doors. They work well out of TPU, and cost me literal pennies to make.
I'm surprised that this video never mentioned flexible PLA. I've become a fan over the last few months, it's so nice that it adheres well to regular PLA. I recommend checking it out.
@@robertd330 I use Flashforge. I use the exact same settings as for my normal Polymaker PLA but I slow down to either 1-2 cubic mm/s or 15-20 linear mm/s with similar results. That's just with a Prusa Mini, so you could probably go faster safely with a different printer. Basically, I just treat it as a color change and then use a modifier to slow down the speed for combined material prints. For all-flex prints I go the volumetric route.
your friction tests...the surface finish of the sample has a huge effect on how "sticky" it is, resistant to forward motion. So then the same material but printed with a smooth vs textured surface will perform quite differently. To add complication they will perform differently in wet vs dry conditions. The supersoft material likely deformed during the test, creating more surface area in contact with the ground surface.
Also the coefficient for sliding friction will never ever exceed static friction. There is no other way except there being loose particles building up while sliding adding up to the drag
Please dont print stuff like that and use it.. there are a ton of chemicals in there you def. dont want your body to take in.. If you really want to get into it, buy some Platinum grade Silicone (quite expensive), mold seperation spray (wax based should be fine) and 3d print your mold, maybe something like PBT to smooth it. You want it smooth, so nothing grows in the fine spaces between the print lines. For coloring, you can use Cosmetic grade mica powder, make sure its fine enough so it doesnt cut itself out of the silicone.
That material mike be idea for printing 'skins' for prosthetic limbs like the Hero Arms. Then get them painted with details to match the wearers skin tone and freckles and the like. It should also be easy to use to make the base shapes for film and TV effects make up pieces, such as Elf/Vulcan ears, Hellboy horn stubs or Twi'lek Lekku for CosPlay, or tentacles for live action Anime.
Im glad you tested coff of friction, up until now i would print tpu and coat it in plasti dip, but now i know what tpe to try for application where i need friction. Thanks!
A lot of combat robots nowadays use TPU as armor, it'd be interesting to see how different TPE materials could be used in that application, resisting cutting and tearing
I can’t speak to combat robots, but I print all my racing drone mounts out of TPU and it can survive hitting trees and PVC at 80+mph all day. I’ll break multiple carbon fiber arms before my camera mount starts to split.
I have printed TPU stuff on an Ender 6 with half a meter Bowden and TPU that's been laying in the basement open for a year.. yet to have issues. Probably just dumb luck. Extrudr Flex Hard was no issues..
Bowden Ender 3, I can print TPU without issues, but if it's undried it spits and blobs. It's awful wet, get it dry and it's acceptable. Now moved to a direct drive neptune 4 plus and it's night and day. Lovely prints but still needs drying in the UK before use.
We use TPU for motor mounts on one of our RC plane kits. The plane is used for full contact combat. I have never had a motor mount break.... yet. Thank you for this great video. Gives me more to think about for future R&D.
@@rm4po4 It's amazing when you get 10 airplanes in the air at one time. It's best if we focus on flying in formation first and then try to make contact. Otherwise it becomes a big ball of nothing for 5-10 minutes.
If you despise glue stick like myself you can try spraying IPA on the plate while removing the print or heating the bed to 100C before detaching it - both methods work for me almost always.
Great video! I 3D print nosecones for my model rockets. Double wall, 5% triangle infill. Creality CR-TPU. Not much bounce. But I want it to survive the landing. And it accepts paint!
I didn't know about that max volumetric setting. That tip alone was worth the watch. I print a lot of engineering grade stuff like nylon and asa, and it really helps to slow the prints down, so I will be using that a lot now. It helps prevent thermal runaways, gives better layer adhesion and dramatically improves the print quality. It even helps with stuff like printing round holes in a perpendicular orientation (they come out more round and less squished looking). I avoid overhangs like the plague because the part cooling fan loves to induce thermal runaways at high nozzle temps, but I would assume it would also help with overhangs and bridging. Probably also help with making supports easier to remove with tricky filaments that don't like supports, like nylon. It's actually interesting how much of this video applies to nylon just as well as to TPU. Right down to the gluestick lol. I actually have really really good results printing nylon on the Prusa satin sheet with a little gluestick rubbed on with IPA. I wonder if that would also work for TPU?
I love that you did this. TPU (and TPEs) are some of my favorite materials (I have from 70A to 75D filaments). Depending on what I need it for, I sometimes don't bother with drying. Drying gives better surface finish, less strings, and probably better layer adhesion... but if all I need is for something squishy, then it's not as important. I've used it for HULA, phone cases, bumpers on rolling tables, wheels on vehicles, kids toys (seriously, all of you printing Toys for Tots and kids toys in PLA and PETG and ABS... print them in TPU instead. They'll be virtually indestructible, make less noise when they impact the ground, extra walls or higher shore hardness means you can make "non flexible" toys out of flexible materials and not damage walls, floors, etc.). I even had a vacuum sealer that had a custom attachment... I designed and printed an adapter out of TPU so it could be used with the standard circular vacuum seal points on generic vacuum bags, and one model I plan to print soon says to print the o-rings to make it water tight in TPU. It can do a lot, and certain brands come in WAY more colors then the 2-5 that many other brands have. May be a case of "US vs. EU" but I feel like the OG king of flexibles was missing: NinjaFlex. And on top of that, one of the most popular filaments, PolyMaker, also has a whole collection of flexibles. Many PLAs start as NatureWorks PLA resin 3D850 or similar, but I can't say "use one TPU, and you've used them all" so would love to see some of the big brands rather then just the EU brands. Outside of that, only real missing item: print on a textured sheet and you can skip the gluestick. It still sticks strongly, but you can peal it off without damage. The airless basketball has been such an interesting one to me... when everyone was going nuts over them, they used PLA. Before seeing the first full video on it, I went "it will bounce at least once... and then crack because PLA doesn't like impacts". And many learned that. PETG (more flexible then PLA and ABS), ABS, they all did this in the end. Finally, someone did TPU... I went "wait, why did you use 95A? That's gonna hit the ground and squish" and it did. I didn't have much reference point on bounciness, so I opted for a 75D TPU so it would be stiff enough to rebound... but still be flexible enough to handle the impact. 100% scale on the XL. It lasted well, some 12 bounces or so... then I tried it on a driveway and it bounced twice. The 2nd bounce, it caught a rock and that little extra bit broke the fine mesh of the ball and it cracked. So while people went all over the materials, the real interest was seeing the 3D models... the one you printed (PartyLime) seems to have done the best "reproduce the design with double lattice structure" that gives it some strength and ability to rebound where as many others basically just made a hollow ball with holes. Actually, looking at it... he apparently released a version and worked with a filament maker to make one with near identical bouncing and supposedly tested it on a court, which is impressive on how far it's come. $2500 vs. $60 and the will power of 3D printing community.
I've had good results with a similar approach. Completely drying filament on the spool takes forever. Placing the filament in a dryer I can print from and drying for an hour or so and then starting the print while the dryer continues to run has made for a time saving process. I use the two Sunlu boxes shown in the video this way.
@@fabianmerki4222 It depends a lot on the climate/humidity. I have 50-60% and higher air humidity almost all the time, so I need to dry filaments a lot. Surprisingly, PLA needs less drying for a good print; and TPU - the softer it is the more drying it needs. Up to 6-7 hours. For my softest TPU I sometimes respool 100-200g of it and dry it separately right before printing - only this way it works...
I print TPU quite a bit, and I have a bowden extruder, I've also never needed to dry the filament, despite living on the coast in England. You do need to print a bit slower, you do need to look at retraction and you do need to get the temperature right. Strangely I find 225c is usually fine.
I have used common 95A TPU on many items. Never have done any drying and my results are good. Stringing does occur but I am usually using TPU for less complex designs where there is not a lot of stringing and removing it is not a big deal. Regarding adhering to my textured PEI bed I just use no heating on the bed and removal is not that bad. I typically use TPU as a shell to install over a PLA case for impact resistance.
What's your go to hard TPU? Used to be able to get decently priced 70D from KVP but they don't appear to make it anymore. Ninjaflex Armadillo gets too rich for my blood pretty quick.....
@@ThantiK So much easier to print than nylon/pc/whatever technical filament you got. Someone should ask/beg Polymaker-Prusa-Greengate-Inland-Sunlu-ESun to mass produce the stuff. I've made gears out of 70D TPU that are stronger and more resiliant than the original injection molded stuff. Why can't we have nice things? lol
@@richardbertacchi5016 New to 3d printing here, but isnt nylon a better choice for gears because of its self lubricating nature and higher temperature resistance?
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@@xavy_ harder to print, but probably yes. I don't have an enclosed printer.
On smooth PEI you definitely need a release agent but I find that it's not a problem on textured sheets, and print on them with no additives. Adhesion is strong but not dangerously so. But do a quick test in a corner before you risk ruining your sheet!
I don't have a filament dryer (or heated drybox), but with my regular airtight storage bin with desiccant I am able to successfully dry my TPU by placing the whole box where the sun would hit it by a south-facing window. I just use a cheap 2-pound pack of color-indicating silica gel beads, and recharge them after the first day or two. It takes a bit of forethought, but after 3-4 days it prints like a dream. This will be faster in warm climates, but up in the chilly midwest it takes a bit of patience!
I've been printing Sunlu TPU 95a at 11 mm3/s. I've never had much issues with it, but if I'm printing more than one part on the build plate it will string quite a lot.
I print directly out of a dryer for all filaments due to my short story... My first roll of TPU was Creality green. I printed with it on an Ender V2 and didn’t have great results. I learned about drying and used a dehydrate function on my air dryer to dry. Prints would start great then fail halfway. Long story short, It absorbed moisture so fast I could dry for 8 hours and within 2 hours it was bubbling again. I threw away about half a roll of TPU because I couldn’t get it to print reliably on 3 different printers. I changed TPU brands and now I have nothing but great results.
I had printed TPU before ( maybe too wet as I learned right now ) and the results were acceptable. Lately I switched to a 0.3mm nozzle and I just tried to print my TPU again with a total failure. So I learned the hard way not to print TPU with a 0.3mm nozzle but that gives a hint to try it with a 0,6mm - maybe this gives even better results. Thanks a lot for your very interesting video !
I use PEBA a lot. I used to use TPU95A or 98A, but I found PEBA to be even better. My application is parts for FPV drones - they take a LOT of physical abuse (eg flying into solid object at 50MPH) It keeps it's elasticity down to a lower temperature. It bonds well with Nylon - an inner core of Nylon and an outer coating of PEBA is insanely durable and still quite rigid It's lighter than TPU
I've found that when printing TPU in an enclosure, larger retraction numbers leads to a loss in print quality, and sometimes a jammed extruder. My theory is that over long periods the extruder heat break starts to get hot because of the high ambient temperature in the enclosure, this leads to the TPU getting soft in the heat break and therefore leads to filament jams because it's just stretching vs. actually retracting, aka just acting like a spring. I've found small retraction numbers work better. If you have stringing or bubbling it's most likely your printing temperature is too high, or the filament is wet. Limiting the volumetric flow just like you've mentioned is key. You might say just open the doors on the enclosure, but I've found there are advantages of printing at a higher ambient temperature, including a reduction in shrinking.
Pretty cool! Very in depth and your research gives a lot of good info for designs with these materials. You didn't test compression strength, however. Also, you should augment your stress tests by noticing when plastic (*pun*) deformation takes place. You'd have to ladder your tests and compare relaxed height to notice. With these flexibke materials especially, it's hard to tell when it was a partial deform vs a complete break, and this augmentation would help inform this.
The materials aren't dangerous to you since the fibers are embedded in the plastic and will not magically leave it unless you burn the plastic away. How safe these fibers are depends on the diameter of the fibers. I don't know about other countries, but here in Europe most commodity plastic manufacturers have switched to fiber diameters that are considered harmless for workplace safety reasons.
For TPU, I disabled retraction. I print with 30 C bed heat. I also had great success printing at 230 C. I came by the 230 C by manually pushing the filament while heating and picking a number 10 C above that. The on spool recommendations seemed very high to me given that TPU liquifies at a lower temp.
You could use it for RC car chassis, ship hull, or plane wing. Set it to be strong enough to take the lift and air resistance, but soft enough to not break if you crash. If it can withstand fuel, like gasoline, you could store fuel in the wings like real planes, and integrate the fuel tank into the chassis to save space
I designed a 3d-printable Ankle/Foot orthosis (FIDIM) for use with Nylon. That works great, but I've always been extremely impressed with the durability of TPU materials. The hinges on FIDIM are made from it. I'd really like to try a stiffer TPU for these now.
What i learned since i startet 3D-printing TPU nearly 23 years ago is to put some gluestick on the printplate. Since then i am able to reconnect all TPU / TPE parts. This also works great with glas printplate to not chip them (allways a problem with ULTIMAKER)
I have a Flsun Super Racer, and for those who know it, they will understand that it is difficult to print with TPU (95A shore) because it has a really long bowden tube. However, I managed to create a profile on Cura that allows me to always get "good prints," at the expense of a bit of stringing. The main problem I faced was the retraction speed. I spent days adjusting that value, but nothing seemed to work. So, I solved it simply by removing the retraction. To compensate for the stringing that forms, I raised the Z-hop speed to 200 mm/s and the travel movements to 350 mm/s, thereby reducing the probability of stringing. As for the brand of filament for the TPU, I used ZIRO.
One of the best investments I made for 3d printing, was dedicated filament dryers for machines. Its made printing things like TPU, and Nylons a extremely reliable process. I live in an area with an average humidity of 95%. Air conditioning is also not common. So Not only do i dry my filament before printing. But I run the dryers while printing (requires a bit of thermal tweaking on filament profiles for temp based on time and flowrate). When printing TPE's at 0.04mm layer heights and a 0.2mm nozzle, you can see a noticeable difference when you hit areas that have high humidity, as it causes the dark filaments to cloud and lighten.
I am really in love with my EIBOS Series X: Easdry Filament Dryer. It is super cheap (50$ including Shipping) it is small, can be directly printed from. Has a fresh air fan (so actually is able to remove moisture) and is quiet. I print directly from it, so drying is only required for 1h or so and while printing. Perfect results!
Softness vs grip. That one can be explained by physics easily. The softer the material, the more "squish" it has, thus if it squishes, its surface or contact area becomes bigger and offers more grip or traction, exactly like in racing, where when maximizing grip, people will oftern take air OUT of the tire to have it conform easier to whatever it's sitting on and having a bigger contact patch since it squishes more with less aire pressure. Also on a second part of the answer, the softer the material, the more it will deform and give before actually moving. On top of that, the bounce back after finally having deformed as much as it could before moving releases the energy towards the pull direction and can create a braking effect making it harder to actually move it since it is now fighting back against the pull force, thus possibly explaining also why at some point it requires more force to keep it moving that actaully getting it to initially move. If all this happens on a very short timeframe (think bouncing back and forth many times a second due to it constantly being pulled) then basically you're releasing and ressetting that braking effect without really seeing it occur.
I haven't found much info on TPE filaments, so bought some from 3DPrintingCanada. The soft rubber feel is similar to overmolding grips in consumer products, really neat. I noticed a significant difference in friction coefficient when comparing tpu and a rubber-like tpe, where the tpe had much better grip with the same hardness. Lastly, couldn't get my prints to stick to a textured pei bed using tpe. Tried several different tapes, but finally tried packing tape and worked perfectly! 40C bed. Parts stick very well, are still simple to remove, and the tape comes off easily because of the low bed temperature. I've had good success setting retraction to zero, and minimizing travel movements to the absolute minimum. Use more walls/concentric infill for top/bottom to avoid those pesky gaps in rectilinear. Makes for some very well filled in parts :)
If you don't use glue, try pouring some isopropyl alcohol on the print once done. It reduces the strength of the bed bond after printing by 90% and it makes it easy to peel off. :)
I love flexibles. The results are so strong and have lots of uses. I've made replacement feet for an aluminium work platform where the original feet had gone brtittle and broken. Also made Shimano hydraulic brake bleed nipple covers, the originals are really soft and easy to lose when cleaning the bike, the TPU ones are bright green and look cool and are easy to find. We've used it at work to make masking covers for PCB connectors on boards that need conformal coating, much quicker to fit than masking tape, more precise and easy to remove
few key takeaways when I do my tpu tuning, I'm not sure about it's shore hardness but I first tested the vol flow by extruding at a set speed, resulting in 5mm³/s, set that in the slicer, the. proceeding to flow, pressure advance, then retraction, finally got my pa to 0.32, flow rate 1.0, retraction 0.9mm at 30mm/s and yeah, having tpu dry is REALLY crucial to get a successful print!
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You can also measure the static coefficient of friction by putting the material on an inclined plane, and increasing the inclination angle until it starts sliding. You can easily measure the coefficient of friction from the angle: f = tan(angle).
Thanks for the video! In particular, thanks for the range you give for Max Volumetric Speeds. This will come in handy as I start experimenting w/ softer tpu / tpe.
I printed some IEM (earbud) tips in 75A TPE and they work great. All the tips that came with the earbuds didn't stay in my ears very well, so I made a (crude) model of my ears with some blu-tack, scanned it in (poorly), and made a model in Blender around it. Not perfect, but it got the job done.
You should do a video with that guy that made the flexible rubber toy that jumps up when you turn it inside out because he found films that were way closer to real rubbers and silicones than anything I’ve ever seen
Well idealized/simplified physics about friction always start with the declaration: for rigid bodies and smooth surfaces. That is why your "anomalies" showed up. For flexible materials friction coefficients are not static. Think of temperatures affecting tyres or how their deformation changes how much friction they have. Try a much heavier weight and you should be getting higher friction coefficient.
Thank you for finally explaining something, I've never had to dry my filaments to get reasonable surface finish, even my black TPU. I guess it's because I print my filaments at the lower temps. Usually 220C for a roll I have sitting out in 30-60% humidity..
For flexibles, I have so many tiny spots where filaments can grab. So, I have to decrease the retraction distance, but usually increase the retract speed to get it out of the way fast. And otherwise avoid retractions when possible.
IMO one should always work with the maximum volumetric speed. It allows to define the material dependency of the printing speed, even for materials like ABS. The 1D speed limit on the printer movement in X/Y should be used to reflect the mechanical properties of the printer. Also, instead of retraction I recommend to calibrate linear advance properly, if the printer supports it. Retraction is just a poor-man's version of linear advance ;-)
Hi there. Your Setup for the friction test does not work for flexible materials. In addition to the force to overcome the friction, you will use a part of your measured force to elongate the flex material, so your measured force will include friction and elongation (yo can already see the deformation with the softer stuff in your video). That would also explain your abnormal behavior with the greater sliding friction. A better setup would be a simple ramp with adjustable slope. Put your material with some weight on the ramp and increase the slope until it starts moving. From the slope you can calculate your friction coefficient. At least the static friction coefficient should be measurable with this.
I built a heated chamber around my super cheap printer. The spool holder is in the chamber. I usually set the temp to the drying temp of the filament as that is usually a good temp to prevent warping. Then I just store the filament in desiccant box. Never have to worry about drying. Just used some cheap parts like a heat gun and some purple foam from HD for the chamber. Put the electronics outside the chamber....flexibles are probably my favorite filaments because the layers bond so well And I never have to worry about the part breaking.
I use an electric skillet set at its lowest setting filled with rice or beans (uncooked, of course) and then i sit my cereal boxes slightly buried in the rice and cover the whole thing with a big enough box box. this way the rice acts as a heat buffer. No airflow whatsoever, but it is still good enough to reduce low levels of moisture. i also put my cereal boxes inside of my car on hot sunny days. again..not as effective since there is no airflow, and a really sunny day could potentially ruin PLA, but it is also a very good option.
My volumetric flow for Ninja Flex (85a) is 6mm/s³. That's with an extruder and hotend combo I designed specifically for TPU on a highly modified Ender 3V2. It's my printer for flexibles while my Vorons and Bambu do everything else. As for bed adhesion, no glue or anything on a textured surface and I have no issues. The trick, set your end Gcode to set you bed temp for 80c. Having the bed heated up significantly increases the ease of getting TPU prints off the bed.
You can print TPU easily on a bowden tube printer if you use a tight bowden tube like the Capricorn brand and decrease your retraction distance dramatically to something like 1.3mm max. That low setting also helps with printing PETG. Sometimes you have to disconnect your bowden tube connector from the extractor end to feed the TPU line in through it though because it sometimes hangs up on the edge of the tube and connector and won't get started through but once you get it in you can screw the connector back in.
That's for soft TPU.. Harder ones, you print basically like a slow PLA print, even on stock, wide Bowdens but with far bigger retraction numbers. I have used up to 13mm at the extruder... but with a 65cm long bowden it was 1.9mm at the nozzle.
that filaflex material seems like it'd be great for making grippy pads for a tracked vehicle. i would probably suggest something like a plug and socket design rather than trying to print it directly onto the track plates with a multi-filament printer though. also great for anti-slip features in general, be they feet or mounts
Experience: I found a video (from uncle Jessie "Can you 3D Print your own $2,500 Airless Basketball?" for printing balls with overture super pla+. I tried it and it was so worst print experience ever. It warps like ABS without enclosing. I tried to print gears - unuseable. Maybe you will try it for your bouncing experiments. But I like to use TPUs - never had problems printing it at about 60-70mm/s (Ender 3S1) - and yes, keep them dry! The filament dryers are garbage, they do not release the wet air and replace it with fresh cold (and dry in abs. humidity). I store them in cereal box with humidity meter and replace desecant if display goes over 20%.
I love TPU 95, prints very well on my old direct drive upgraded Ender 3 and the parts are nearly indestructible. One of the best functional printing materials for durable parts if great stiffness is not required and of course great for parts where flexibility is desired like plugs, seals, protective covers, bumpers etc. I have not yet tried the more flexible materials but I would like to when I have the time.
Hello Stefan, can you make a video on the subject of fine dust and 3D printing, as well as the vapors when printing ABS/ASA and how best to deal with them?
There's a TPE that's described as having a "skin like" feel, for certain products. I wonder of it could be printed in to gloves for "hero arm" style prosthetic limbs? This way the artificial limb could look more like a normal arm and hand, and allow the wearer to have more grip at a lower pressure application when picking things up, such as using a spoon or cracking an egg. Perhaps that 60A is worth a try for this, and then get make-up artist to add freckles and the like to match the wearers skin tones and details. Locally, finding retailers with TPE's in stock is harder then trying to print them. They're also pretty abrasive to brass nozzles.
I keep my filaments in plastic boxes with plenty of silica gel on bottom. (dirt cheap if you buy the kitty litter quality in large bags). I have a kind of bowden style tubes for filament takeoff. I mount the selected ptfe tube close to printer and the rest of tubes loop back to a quick link connector on box. Any large enough box will do and some tubing can be mounted to hold several rolls in a row. Food drier and/or vacuum are some methods I've used to dry other filament. After they are dry, they keep dry and print from the box.
I never put glue stick on my print beds. Just make sure you have a properly levelled build surface. I usually print TPU on my smooth PET surface and I cannot complain about too weak or too strong bed adhesion. Same applies to my Ender 2 with stock surface and bowden setup. I lowered the print speeds drastically on the ender, btw.
*What's your experience with flexible materials?*
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Is that preview image text supposed to say "Thermo Plastic Elastomers"?
I don't have any, but what type of filament should I use for belts, or like tires?
The biggest problem printing with TPU for me has been getting proper layer adhesion along the XY axis. Maybe I need to adjust line width, but for whatever reason the TPU bonds well along the vertical axis but not the horizontal. Any suggestions?
Hello stefan,
Thank you for the nice and insightful video!
I have a couple of suggestions to test based on my experience with TPE filaments:
Temperature greatly changes stiffness of TPU. I have printed powepads for my EUC. at -20°c they shattered instantly from small impact.
It was printed from purple transparent TPU from esun which gets to my second point/question:
Does transparency or colour affect material properties?
I also have parts printed from extrudr medium anthracite (grey), it still holds up fine.
I have also noticed creeping issues with TPU.
Even under small load they will slowly give up and permanently change form.
I have noticed this from several different applications, biggest one was kickstand for EUC which made it unusable because it gave up on one side and will always flip to that side. It worked fine for couple of days until it started to give in.
I printed thin PETG supports to fix that issue.
That brings my fourth thought, would heat treatment (annealing)help with this issue, or are there TPU filaments that doesn't do that.
(It also happens with PLA, you cannot print springs or compliant mechanism that are stored as momentarily "deformed state". It will slowly give in.
Also side note: I have noticed
PP, to have a considerable amount of friction compared to it's shore hardness. It is also really nice material.
I printed some inserts for a tablet holder from TPU. It was as easy as you said (bed adhesion is amazing - the brim I added was completely unnecessary) and I was blown away by the seemingly indestructible parts I got. However, they're not as soft as I had hoped. Most generic TPUs you can buy are 95A shore hardness, which is just too hard for the "rubbery" effect I was going for. I want to try 30D next.
Overall an excellent video, the only thing I think not mentioned was price - unfortunately, TPEs are all quite expensive, with the softer ones easily going into the 80€/kg range.
One thing while printing flexible materials i learned the hard way is to also lower your non-print speeds when printing tall models. Bed slingers tend to cause quite a bit of wobbling and models can get misaligned
So I cam use a very height speed with corexy printer?
@@timgromeyer2061As long as the printhead isn't causing vibrations on the whole printer. I believe input shaping fixes this issue anyway.
@@timgromeyer2061 No idea, sorry. I would assume that since with delta or corexy the model itself doesn't move in x or y direction the movement speed shouldn't matter.
I mainly use bed slinger for my printing and this is the first time i encountered this sort of problem with any filament.
I admit i was also bit greedy and wanted to cheap out on structure and some of the supports and adding some more mass to model made it a lot more stable.
@@PJ-oe6eu I mean the whole model was physically shaking when moving on Y-axis :D
The issue with bed slingers is not speed but acceleration. So you can keep print speed on "bed-axis" but drastically decrease acceleration. You could also reduce acceleration by height, so the total print time is even lower
4:22 "I can't really wrap my head around what to print with this"
Oh I think you already know, judging by what's printing in the background. I'm sure Mrs. Stefan is quite pleased.
Oh, those German stereotypes strike again 😅.
But... Layer lines 💀💀
@@LouisLeXVIII TetraHydroFuron smooths TPU like acetone on ABS… but it is not safe compared to acetone.
… just incase anyone wanted to know 😉
so i wasnt the only one that noticed.
then the same filament found its way into "any small crack it can find" @ th-cam.com/video/4InFd5DoZa4/w-d-xo.html
4:20 What are you printing there Stefan? 👀
A "test cylinder" ;-)
I mean he was thinking HARD about what to print it seems
What do you think?
@@willcubemakesDILDOOOOOOOOOO !!!!!!!!! FLEXIBLE DILDOOOOOOOOO !!!!!!!!!!!!!!!!!!!❗️❗️❗️❗️❗️❗️❗️❗️❗️❗️❗️❗️❗️‼️‼️‼️‼️‼️‼️‼️
@@dextrodusmaybe we get a clue if Stefan releases a video testing 3d scanners in the near future.
Someone in the Rat Rig Facebook group gave me great advice that really works: When the print finishes rather than tear it off the bed pour a little bit of isopropyl alcohol or similar around its edges. I had trouble with phone cases that kept getting deformed when pulled off the bed. This solved it completely.
The alcohol gets under the print I think via some capilarry action and almost releases the print from the bed. The force needed to peel it off the bed is reduced to something that feels like 10% of what it was before. I have tried it with several TPUs that before tended to damage my powder coated PEI sheet and it works beautifully. With G10 smooth surface it works too but a bit slower. After getting it off the bed this way I just have to let it dry out the alcohol from its pores.
I do the same thing but I keep my isopropyl in a spray bottle, & spray it at the base
I also use a flexible bed which helps a lot
@@MartianMoon All my beds are flexible too, but especiall with relatively low height parts with big foorprint the printed part is sometimes more flexible than the bed 🙂.
I buy the IPA in plastic bottle with a tiny opening on top so it is easy to squirt a thin stream of it around the base of the print too.
Nice!
I will try that out.
Does this eliminate the need for a glue stick?
@BaghaShams for textured PEI and G10 I know for sure it does. I never use glue stick. I am guessing that for smooth PEI it works also without gluestick but I don't have one to test it.
My favorite use for TPE is printing gaskets, though I'd really like some purpose-built ultra-soft filament with excellent chemical resistance specifically designed for it.
Man, I wish there was an ultimate filament properties chart. Where all types and brands can be compared to each other.
That’s a great idea, shocked no one’s done it.. would be down even for some heavy monetization if any board software developer may be reading this.. 😂
Prusa has a table with many materials and brands on their site that is really simple and intuitive.
I’ve used it a couple of times to check the best brand and material for some of my projects :)
help.prusa3d.com/materials
Isnt there a website showing comparisons already?
Slant 3d is gathering up test equipment to do just that. I can't wait.
I legit allways use TPU when possible. It is basically indesctrucable ! And The Layer adhesion is sooo good. I have 2 Waterbottle holders for my bike printed in TPU, every other material cracked after a while cause of the impacts of the full waterbottle but the tpu one still works just fine!!
Can you recommend some very hard TPE ? I have some TPU over here but it's very soft and hard to print on my ender 3 with Bowden drive. I don't know the shore hardness. I don't even know the brand.
@@Saeschboy You can just buy hard TPU, most is quite flexible, but some sell multiple varieties, including hard ones.
Basically indestructable to hard forces.
Even with direct drive and using external feed the very soft Ninjaflex TPU doesn't print well on an X1C.
@@tarakivu8861It's a shame the hard TPUs are so expensive though. Anything above 95A is ridiculous.
There is 64D and 74D hardness TPU available which sounds incredibly useful but it's like $1 per gram.
What brand of TPU do you use? I only have experience with one, and I wasn’t too impressed.
I actually slightly oil the bed for TPU: Put a drop on the PEI and distribute it. Then wipe it off with a dry cloth. Works great for me. (I use some fine mechanics oil.)
I replaced the broken tires on my luggage with TPU. Works a charm.
... and Every Bourbon is a whiskey, but definitely not every whiskey is a bourbon! The maximum volumetric speed was one of the best discoveries that I've made in 4 years of printing.
17:54 That moment of inertia formula that you used, works for rigid bodies. For a pipe it's only relevant for determining its resistance to buckling, but for comparing the overall stiffness of the pipe you'd want to use a formula where you take the area times the distance to the centroid axis.
The current best use for TPU for me personally has been airsoft and cosplay, TPU is fantastic for Absorbing BB's in armor. And the flexability make it super nice to wear aswell
Cura, in their infinite wisdom, actively rejects community efforts to add a maximum volumetric flow rate into the slicer.
The flexible filaments can be used to print replacement covers for electronic equipment. For examples, the little "hatches" on cameras that cover the HDMI, phone, mic... plugs. These parts are often not available (especially with older cameras) and so worth printing.
Have you seen NathanBuildsRobots address the risks of fiber filled filaments? Highly recommend you be more careful with carbon and glass fiber
So much information-and work to get this all together for us in a highly organized package. You're the best! (Aside: I've had the Recreus 60A for I think two ears now and I still haven’t decided what to print with it!)
Hey Courtney! What's the story on why hardly anyone makes a hard (50D to 70D or higher) TPU? (THANKS, If anybody knows it's be you)
Copolyesters in particular tend to bond really well to PETG. If you have a multimaterial printer, it opens up a lot of design possibilities.
Even through a bowden tube I find myself using more retraction than is ever recommend for tpu.
I like to use the purple glue stick because of the PVA in it.
Drying the filament makes the biggest difference!
Another really good TPU is the Ninjatek Armadillo. It's tough as shit, and you can print it faster. It has great industrial applications, and I feel it's being slept on.
I have a small home based business that 3D prints TPU products, so I appreciated this flexible filament video. I'm an engineer so I always like Stefan's data driven approach. I know from past CNC Kitchen videos that I can't get most of these filaments in the US but I appreciate the links to the filaments. I need a more energy absorbing material for a product that hasn't been converted to 3D printing and I need to try the foaming TPU but it's never in stock.
Used TPU to 3D print a door stop. I was looking at all the poor designs and lamenting spending $5 to $10 on crappy commercial one made of rubber that I had already seen fail. So I designed and printed some. The other benefit is that it can be easily modified for larger gaps or heavier doors. They work well out of TPU, and cost me literal pennies to make.
I also made my own door stop. Needed a tall one that could take a beating. Plus, when you work out the weight its cheaper to just print it.
I'm surprised that this video never mentioned flexible PLA. I've become a fan over the last few months, it's so nice that it adheres well to regular PLA. I recommend checking it out.
That sounds interesting. Can you recommend a specific brand that you use?
@@robertd330 I use Flashforge. I use the exact same settings as for my normal Polymaker PLA but I slow down to either 1-2 cubic mm/s or 15-20 linear mm/s with similar results. That's just with a Prusa Mini, so you could probably go faster safely with a different printer. Basically, I just treat it as a color change and then use a modifier to slow down the speed for combined material prints. For all-flex prints I go the volumetric route.
your friction tests...the surface finish of the sample has a huge effect on how "sticky" it is, resistant to forward motion. So then the same material but printed with a smooth vs textured surface will perform quite differently. To add complication they will perform differently in wet vs dry conditions. The supersoft material likely deformed during the test, creating more surface area in contact with the ground surface.
Also the coefficient for sliding friction will never ever exceed static friction. There is no other way except there being loose particles building up while sliding adding up to the drag
flesh colours soft fillament? na i can't think of anything to print with it either 🙄🙄
Na, but you might have to add some blue to increase shore hardness on those.
Would expect the counterpart oft what he prints in the background but hey... No judging😂
Please dont print stuff like that and use it.. there are a ton of chemicals in there you def. dont want your body to take in..
If you really want to get into it, buy some Platinum grade Silicone (quite expensive), mold seperation spray (wax based should be fine) and 3d print your mold, maybe something like PBT to smooth it.
You want it smooth, so nothing grows in the fine spaces between the print lines.
For coloring, you can use Cosmetic grade mica powder, make sure its fine enough so it doesnt cut itself out of the silicone.
@@tarakivu8861 Not just chemicals, there's no way a porous-by-nature 3D print is going to stay clean.
That material mike be idea for printing 'skins' for prosthetic limbs like the Hero Arms. Then get them painted with details to match the wearers skin tone and freckles and the like.
It should also be easy to use to make the base shapes for film and TV effects make up pieces, such as Elf/Vulcan ears, Hellboy horn stubs or Twi'lek Lekku for CosPlay, or tentacles for live action Anime.
Just applied to work with Zellerfeld. Wish me luck!
good luck buddy!
I love printing print in place flexible things like those wiggly dragons out of TPU. Super shiny and nearly indestructible for kids.
Im glad you tested coff of friction, up until now i would print tpu and coat it in plasti dip, but now i know what tpe to try for application where i need friction. Thanks!
A lot of combat robots nowadays use TPU as armor, it'd be interesting to see how different TPE materials could be used in that application, resisting cutting and tearing
I can’t speak to combat robots, but I print all my racing drone mounts out of TPU and it can survive hitting trees and PVC at 80+mph all day. I’ll break multiple carbon fiber arms before my camera mount starts to split.
I've been printing un-dried TPU on a bowden tube extruder for years. Yolo.
I guess most of my success has been printing it at 230 and slowly.
same lol it prints like shit
I have printed TPU stuff on an Ender 6 with half a meter Bowden and TPU that's been laying in the basement open for a year.. yet to have issues. Probably just dumb luck. Extrudr Flex Hard was no issues..
Bowden Ender 3, I can print TPU without issues, but if it's undried it spits and blobs. It's awful wet, get it dry and it's acceptable. Now moved to a direct drive neptune 4 plus and it's night and day. Lovely prints but still needs drying in the UK before use.
We use TPU for motor mounts on one of our RC plane kits. The plane is used for full contact combat. I have never had a motor mount break.... yet.
Thank you for this great video. Gives me more to think about for future R&D.
That sport sounds crazy.
@@rm4po4 It's amazing when you get 10 airplanes in the air at one time. It's best if we focus on flying in formation first and then try to make contact. Otherwise it becomes a big ball of nothing for 5-10 minutes.
This is the video I’ve been waiting for. Thank you for struggling through these tests! Your sacrifices are appreciated.
Appreciate it! This was way more work than anticipated yet I still feel there is so much more to talk about and test.
This is a valuable video! Many thanks for your efforts in highlighting all aspects 🙌
..and happy you like the Filament Bunker :)
If you despise glue stick like myself you can try spraying IPA on the plate while removing the print or heating the bed to 100C before detaching it - both methods work for me almost always.
Great video!
I 3D print nosecones for my model rockets. Double wall, 5% triangle infill. Creality CR-TPU. Not much bounce. But I want it to survive the landing. And it accepts paint!
I didn't know about that max volumetric setting. That tip alone was worth the watch. I print a lot of engineering grade stuff like nylon and asa, and it really helps to slow the prints down, so I will be using that a lot now. It helps prevent thermal runaways, gives better layer adhesion and dramatically improves the print quality. It even helps with stuff like printing round holes in a perpendicular orientation (they come out more round and less squished looking). I avoid overhangs like the plague because the part cooling fan loves to induce thermal runaways at high nozzle temps, but I would assume it would also help with overhangs and bridging. Probably also help with making supports easier to remove with tricky filaments that don't like supports, like nylon.
It's actually interesting how much of this video applies to nylon just as well as to TPU. Right down to the gluestick lol. I actually have really really good results printing nylon on the Prusa satin sheet with a little gluestick rubbed on with IPA. I wonder if that would also work for TPU?
I love that you did this. TPU (and TPEs) are some of my favorite materials (I have from 70A to 75D filaments). Depending on what I need it for, I sometimes don't bother with drying. Drying gives better surface finish, less strings, and probably better layer adhesion... but if all I need is for something squishy, then it's not as important. I've used it for HULA, phone cases, bumpers on rolling tables, wheels on vehicles, kids toys (seriously, all of you printing Toys for Tots and kids toys in PLA and PETG and ABS... print them in TPU instead. They'll be virtually indestructible, make less noise when they impact the ground, extra walls or higher shore hardness means you can make "non flexible" toys out of flexible materials and not damage walls, floors, etc.). I even had a vacuum sealer that had a custom attachment... I designed and printed an adapter out of TPU so it could be used with the standard circular vacuum seal points on generic vacuum bags, and one model I plan to print soon says to print the o-rings to make it water tight in TPU. It can do a lot, and certain brands come in WAY more colors then the 2-5 that many other brands have.
May be a case of "US vs. EU" but I feel like the OG king of flexibles was missing: NinjaFlex. And on top of that, one of the most popular filaments, PolyMaker, also has a whole collection of flexibles. Many PLAs start as NatureWorks PLA resin 3D850 or similar, but I can't say "use one TPU, and you've used them all" so would love to see some of the big brands rather then just the EU brands. Outside of that, only real missing item: print on a textured sheet and you can skip the gluestick. It still sticks strongly, but you can peal it off without damage.
The airless basketball has been such an interesting one to me... when everyone was going nuts over them, they used PLA. Before seeing the first full video on it, I went "it will bounce at least once... and then crack because PLA doesn't like impacts". And many learned that. PETG (more flexible then PLA and ABS), ABS, they all did this in the end. Finally, someone did TPU... I went "wait, why did you use 95A? That's gonna hit the ground and squish" and it did. I didn't have much reference point on bounciness, so I opted for a 75D TPU so it would be stiff enough to rebound... but still be flexible enough to handle the impact. 100% scale on the XL. It lasted well, some 12 bounces or so... then I tried it on a driveway and it bounced twice. The 2nd bounce, it caught a rock and that little extra bit broke the fine mesh of the ball and it cracked. So while people went all over the materials, the real interest was seeing the 3D models... the one you printed (PartyLime) seems to have done the best "reproduce the design with double lattice structure" that gives it some strength and ability to rebound where as many others basically just made a hollow ball with holes. Actually, looking at it... he apparently released a version and worked with a filament maker to make one with near identical bouncing and supposedly tested it on a court, which is impressive on how far it's come. $2500 vs. $60 and the will power of 3D printing community.
just print it while drying in a food dryer. 20min heating at 60° is enough, saves a lot of energy.
I've had good results with a similar approach. Completely drying filament on the spool takes forever. Placing the filament in a dryer I can print from and drying for an hour or so and then starting the print while the dryer continues to run has made for a time saving process. I use the two Sunlu boxes shown in the video this way.
@@fabianmerki4222 It depends a lot on the climate/humidity. I have 50-60% and higher air humidity almost all the time, so I need to dry filaments a lot. Surprisingly, PLA needs less drying for a good print; and TPU - the softer it is the more drying it needs. Up to 6-7 hours. For my softest TPU I sometimes respool 100-200g of it and dry it separately right before printing - only this way it works...
I print TPU quite a bit, and I have a bowden extruder, I've also never needed to dry the filament, despite living on the coast in England. You do need to print a bit slower, you do need to look at retraction and you do need to get the temperature right. Strangely I find 225c is usually fine.
I have used common 95A TPU on many items. Never have done any drying and my results are good. Stringing does occur but I am usually using TPU for less complex designs where there is not a lot of stringing and removing it is not a big deal. Regarding adhering to my textured PEI bed I just use no heating on the bed and removal is not that bad. I typically use TPU as a shell to install over a PLA case for impact resistance.
Great video, the amount of work required to create a video of this quality must have been huge 👏
Hard TPU is my default filament! Probably harder than any in this test, 70D or so.
What's your go to hard TPU? Used to be able to get decently priced 70D from KVP but they don't appear to make it anymore. Ninjaflex Armadillo gets too rich for my blood pretty quick.....
Finally, someone who gets it. We should all be focused on _harder_ TPUs not softer ones.
@@ThantiK So much easier to print than nylon/pc/whatever technical filament you got. Someone should ask/beg Polymaker-Prusa-Greengate-Inland-Sunlu-ESun to mass produce the stuff. I've made gears out of 70D TPU that are stronger and more resiliant than the original injection molded stuff. Why can't we have nice things? lol
@@richardbertacchi5016 New to 3d printing here, but isnt nylon a better choice for gears because of its self lubricating nature and higher temperature resistance?
@@xavy_ harder to print, but probably yes. I don't have an enclosed printer.
On smooth PEI you definitely need a release agent but I find that it's not a problem on textured sheets, and print on them with no additives. Adhesion is strong but not dangerously so. But do a quick test in a corner before you risk ruining your sheet!
I don't have a filament dryer (or heated drybox), but with my regular airtight storage bin with desiccant I am able to successfully dry my TPU by placing the whole box where the sun would hit it by a south-facing window. I just use a cheap 2-pound pack of color-indicating silica gel beads, and recharge them after the first day or two. It takes a bit of forethought, but after 3-4 days it prints like a dream.
This will be faster in warm climates, but up in the chilly midwest it takes a bit of patience!
I've been printing Sunlu TPU 95a at 11 mm3/s. I've never had much issues with it, but if I'm printing more than one part on the build plate it will string quite a lot.
Thanks for the hard work on doing use cases and examples to demystify these filiments.
I print directly out of a dryer for all filaments due to my short story...
My first roll of TPU was Creality green. I printed with it on an Ender V2 and didn’t have great results. I learned about drying and used a dehydrate function on my air dryer to dry. Prints would start great then fail halfway. Long story short, It absorbed moisture so fast I could dry for 8 hours and within 2 hours it was bubbling again.
I threw away about half a roll of TPU because I couldn’t get it to print reliably on 3 different printers. I changed TPU brands and now I have nothing but great results.
I had printed TPU before ( maybe too wet as I learned right now ) and the results were acceptable. Lately I switched to a 0.3mm nozzle and I just tried to print my TPU again with a total failure. So I learned the hard way not to print TPU with a 0.3mm nozzle but that gives a hint to try it with a 0,6mm - maybe this gives even better results.
Thanks a lot for your very interesting video !
I use PEBA a lot. I used to use TPU95A or 98A, but I found PEBA to be even better.
My application is parts for FPV drones - they take a LOT of physical abuse (eg flying into solid object at 50MPH)
It keeps it's elasticity down to a lower temperature.
It bonds well with Nylon - an inner core of Nylon and an outer coating of PEBA is insanely durable and still quite rigid
It's lighter than TPU
I've found that when printing TPU in an enclosure, larger retraction numbers leads to a loss in print quality, and sometimes a jammed extruder. My theory is that over long periods the extruder heat break starts to get hot because of the high ambient temperature in the enclosure, this leads to the TPU getting soft in the heat break and therefore leads to filament jams because it's just stretching vs. actually retracting, aka just acting like a spring.
I've found small retraction numbers work better. If you have stringing or bubbling it's most likely your printing temperature is too high, or the filament is wet. Limiting the volumetric flow just like you've mentioned is key.
You might say just open the doors on the enclosure, but I've found there are advantages of printing at a higher ambient temperature, including a reduction in shrinking.
Pretty cool! Very in depth and your research gives a lot of good info for designs with these materials. You didn't test compression strength, however. Also, you should augment your stress tests by noticing when plastic (*pun*) deformation takes place. You'd have to ladder your tests and compare relaxed height to notice. With these flexibke materials especially, it's hard to tell when it was a partial deform vs a complete break, and this augmentation would help inform this.
Got some esun tpe 83 on sale last month, been having fun with it
Made a phone case out of a foaming flexible years ago, loved it
can you make a video about how safe those reinforced materials are to your health? small glass/carbon fibers can be dangerous
I'm thinking about trying iron powder. Iron is naturally in your blood so it's probably not that bad...
The materials aren't dangerous to you since the fibers are embedded in the plastic and will not magically leave it unless you burn the plastic away.
How safe these fibers are depends on the diameter of the fibers. I don't know about other countries, but here in Europe most commodity plastic manufacturers have switched to fiber diameters that are considered harmless for workplace safety reasons.
For TPU, I disabled retraction. I print with 30 C bed heat. I also had great success printing at 230 C. I came by the 230 C by manually pushing the filament while heating and picking a number 10 C above that. The on spool recommendations seemed very high to me given that TPU liquifies at a lower temp.
You could use it for RC car chassis, ship hull, or plane wing. Set it to be strong enough to take the lift and air resistance, but soft enough to not break if you crash. If it can withstand fuel, like gasoline, you could store fuel in the wings like real planes, and integrate the fuel tank into the chassis to save space
Love the Green Octopus! 🤘🐙
I designed a 3d-printable Ankle/Foot orthosis (FIDIM) for use with Nylon. That works great, but I've always been extremely impressed with the durability of TPU materials. The hinges on FIDIM are made from it. I'd really like to try a stiffer TPU for these now.
What i learned since i startet 3D-printing TPU nearly 23 years ago is to put some gluestick on the printplate. Since then i am able to reconnect all TPU / TPE parts. This also works great with glas printplate to not chip them (allways a problem with ULTIMAKER)
I have a Flsun Super Racer, and for those who know it, they will understand that it is difficult to print with TPU (95A shore) because it has a really long bowden tube. However, I managed to create a profile on Cura that allows me to always get "good prints," at the expense of a bit of stringing.
The main problem I faced was the retraction speed. I spent days adjusting that value, but nothing seemed to work. So, I solved it simply by removing the retraction. To compensate for the stringing that forms, I raised the Z-hop speed to 200 mm/s and the travel movements to 350 mm/s, thereby reducing the probability of stringing.
As for the brand of filament for the TPU, I used ZIRO.
One of the best investments I made for 3d printing, was dedicated filament dryers for machines. Its made printing things like TPU, and Nylons a extremely reliable process. I live in an area with an average humidity of 95%. Air conditioning is also not common. So Not only do i dry my filament before printing. But I run the dryers while printing (requires a bit of thermal tweaking on filament profiles for temp based on time and flowrate). When printing TPE's at 0.04mm layer heights and a 0.2mm nozzle, you can see a noticeable difference when you hit areas that have high humidity, as it causes the dark filaments to cloud and lighten.
I am really in love with my
EIBOS Series X: Easdry Filament Dryer. It is super cheap (50$ including Shipping) it is small, can be directly printed from. Has a fresh air fan (so actually is able to remove moisture) and is quiet.
I print directly from it, so drying is only required for 1h or so and while printing.
Perfect results!
Softness vs grip. That one can be explained by physics easily. The softer the material, the more "squish" it has, thus if it squishes, its surface or contact area becomes bigger and offers more grip or traction, exactly like in racing, where when maximizing grip, people will oftern take air OUT of the tire to have it conform easier to whatever it's sitting on and having a bigger contact patch since it squishes more with less aire pressure. Also on a second part of the answer, the softer the material, the more it will deform and give before actually moving. On top of that, the bounce back after finally having deformed as much as it could before moving releases the energy towards the pull direction and can create a braking effect making it harder to actually move it since it is now fighting back against the pull force, thus possibly explaining also why at some point it requires more force to keep it moving that actaully getting it to initially move. If all this happens on a very short timeframe (think bouncing back and forth many times a second due to it constantly being pulled) then basically you're releasing and ressetting that braking effect without really seeing it occur.
I’d love to see a video about flex PLA next. I’ve found it to be very similar to TPU, but WAY easier to print
I haven't found much info on TPE filaments, so bought some from 3DPrintingCanada.
The soft rubber feel is similar to overmolding grips in consumer products, really neat.
I noticed a significant difference in friction coefficient when comparing tpu and a rubber-like tpe, where the tpe had much better grip with the same hardness.
Lastly, couldn't get my prints to stick to a textured pei bed using tpe. Tried several different tapes, but finally tried packing tape and worked perfectly! 40C bed. Parts stick very well, are still simple to remove, and the tape comes off easily because of the low bed temperature.
I've had good success setting retraction to zero, and minimizing travel movements to the absolute minimum. Use more walls/concentric infill for top/bottom to avoid those pesky gaps in rectilinear. Makes for some very well filled in parts :)
If you don't use glue, try pouring some isopropyl alcohol on the print once done. It reduces the strength of the bed bond after printing by 90% and it makes it easy to peel off. :)
I love flexibles. The results are so strong and have lots of uses. I've made replacement feet for an aluminium work platform where the original feet had gone brtittle and broken. Also made Shimano hydraulic brake bleed nipple covers, the originals are really soft and easy to lose when cleaning the bike, the TPU ones are bright green and look cool and are easy to find. We've used it at work to make masking covers for PCB connectors on boards that need conformal coating, much quicker to fit than masking tape, more precise and easy to remove
When CNC Kitchen posts, I click.
few key takeaways when I do my tpu tuning, I'm not sure about it's shore hardness but I first tested the vol flow by extruding at a set speed, resulting in 5mm³/s, set that in the slicer, the. proceeding to flow, pressure advance, then retraction, finally got my pa to 0.32, flow rate 1.0, retraction 0.9mm at 30mm/s and yeah, having tpu dry is REALLY crucial to get a successful print!
You can also measure the static coefficient of friction by putting the material on an inclined plane, and increasing the inclination angle until it starts sliding. You can easily measure the coefficient of friction from the angle: f = tan(angle).
Thanks for the video! In particular, thanks for the range you give for Max Volumetric Speeds. This will come in handy as I start experimenting w/ softer tpu / tpe.
a friction and wear comparison between filaments would be cool!
I printed some IEM (earbud) tips in 75A TPE and they work great. All the tips that came with the earbuds didn't stay in my ears very well, so I made a (crude) model of my ears with some blu-tack, scanned it in (poorly), and made a model in Blender around it. Not perfect, but it got the job done.
Finally someone considers friction!!! The only reason I want a TPU/E
You should do a video with that guy that made the flexible rubber toy that jumps up when you turn it inside out because he found films that were way closer to real rubbers and silicones than anything I’ve ever seen
Sorry I cannot comment, I am still overwhelmed by the great content in the video. Tom last video about infill was good but you've done even better.
Well idealized/simplified physics about friction always start with the declaration: for rigid bodies and smooth surfaces. That is why your "anomalies" showed up. For flexible materials friction coefficients are not static. Think of temperatures affecting tyres or how their deformation changes how much friction they have. Try a much heavier weight and you should be getting higher friction coefficient.
I imagine that the properties of TPEs will change moderately with temperature. The difference between 20 and 30 °C could play a role.
Thank you for finally explaining something, I've never had to dry my filaments to get reasonable surface finish, even my black TPU. I guess it's because I print my filaments at the lower temps. Usually 220C for a roll I have sitting out in 30-60% humidity..
For flexibles, I have so many tiny spots where filaments can grab. So, I have to decrease the retraction distance, but usually increase the retract speed to get it out of the way fast. And otherwise avoid retractions when possible.
BambuLab now has TPU 95A High Flow. They don't sell the normal anymore. The High Flow version has a volumetric of 12mm3/s.
IMO one should always work with the maximum volumetric speed. It allows to define the material dependency of the printing speed, even for materials like ABS. The 1D speed limit on the printer movement in X/Y should be used to reflect the mechanical properties of the printer.
Also, instead of retraction I recommend to calibrate linear advance properly, if the printer supports it. Retraction is just a poor-man's version of linear advance ;-)
Stefan you could 3-d print some elastic bands for a catapult or a slingshot. And even a rubber band, Plane . Being so the elasticity is pretty good.
Hi there. Your Setup for the friction test does not work for flexible materials. In addition to the force to overcome the friction, you will use a part of your measured force to elongate the flex material, so your measured force will include friction and elongation (yo can already see the deformation with the softer stuff in your video). That would also explain your abnormal behavior with the greater sliding friction. A better setup would be a simple ramp with adjustable slope. Put your material with some weight on the ramp and increase the slope until it starts moving. From the slope you can calculate your friction coefficient. At least the static friction coefficient should be measurable with this.
who has ever seen how to test the quality of an anvil will not be surprised about the missing correlation between bouncing and beeing soft.
I built a heated chamber around my super cheap printer. The spool holder is in the chamber. I usually set the temp to the drying temp of the filament as that is usually a good temp to prevent warping. Then I just store the filament in desiccant box. Never have to worry about drying. Just used some cheap parts like a heat gun and some purple foam from HD for the chamber. Put the electronics outside the chamber....flexibles are probably my favorite filaments because the layers bond so well And I never have to worry about the part breaking.
I use an electric skillet set at its lowest setting filled with rice or beans (uncooked, of course) and then i sit my cereal boxes slightly buried in the rice and cover the whole thing with a big enough box box. this way the rice acts as a heat buffer. No airflow whatsoever, but it is still good enough to reduce low levels of moisture.
i also put my cereal boxes inside of my car on hot sunny days. again..not as effective since there is no airflow, and a really sunny day could potentially ruin PLA, but it is also a very good option.
4:03 the "bounceability"
My volumetric flow for Ninja Flex (85a) is 6mm/s³. That's with an extruder and hotend combo I designed specifically for TPU on a highly modified Ender 3V2. It's my printer for flexibles while my Vorons and Bambu do everything else. As for bed adhesion, no glue or anything on a textured surface and I have no issues. The trick, set your end Gcode to set you bed temp for 80c. Having the bed heated up significantly increases the ease of getting TPU prints off the bed.
Indeed. Textured PEI. Printing cold. Heating for removal.
Works great. Still be careful and don't rip it off with too much force.
You can print TPU easily on a bowden tube printer if you use a tight bowden tube like the Capricorn brand and decrease your retraction distance dramatically to something like 1.3mm max. That low setting also helps with printing PETG. Sometimes you have to disconnect your bowden tube connector from the extractor end to feed the TPU line in through it though because it sometimes hangs up on the edge of the tube and connector and won't get started through but once you get it in you can screw the connector back in.
That's for soft TPU.. Harder ones, you print basically like a slow PLA print, even on stock, wide Bowdens but with far bigger retraction numbers. I have used up to 13mm at the extruder... but with a 65cm long bowden it was 1.9mm at the nozzle.
You could use the super soft TPE as an elastic element like a spring
I was looking for information about printing flexible material with my Prusa yesterday, and today Stefan drops this great video. What are the odds!
that filaflex material seems like it'd be great for making grippy pads for a tracked vehicle. i would probably suggest something like a plug and socket design rather than trying to print it directly onto the track plates with a multi-filament printer though. also great for anti-slip features in general, be they feet or mounts
Experience: I found a video (from uncle Jessie "Can you 3D Print your own $2,500 Airless Basketball?" for printing balls with overture super pla+. I tried it and it was so worst print experience ever. It warps like ABS without enclosing. I tried to print gears - unuseable. Maybe you will try it for your bouncing experiments.
But I like to use TPUs - never had problems printing it at about 60-70mm/s (Ender 3S1) - and yes, keep them dry! The filament dryers are garbage, they do not release the wet air and replace it with fresh cold (and dry in abs. humidity).
I store them in cereal box with humidity meter and replace desecant if display goes over 20%.
I use eSUN TPE 83A. It works really well, and I printed some custom anti-vibration feet for my Bambulab X1C
I love TPU 95, prints very well on my old direct drive upgraded Ender 3 and the parts are nearly indestructible. One of the best functional printing materials for durable parts if great stiffness is not required and of course great for parts where flexibility is desired like plugs, seals, protective covers, bumpers etc. I have not yet tried the more flexible materials but I would like to when I have the time.
Hello Stefan,
can you make a video on the subject of fine dust and 3D printing, as well as the vapors when printing ABS/ASA and how best to deal with them?
There's a TPE that's described as having a "skin like" feel, for certain products. I wonder of it could be printed in to gloves for "hero arm" style prosthetic limbs? This way the artificial limb could look more like a normal arm and hand, and allow the wearer to have more grip at a lower pressure application when picking things up, such as using a spoon or cracking an egg. Perhaps that 60A is worth a try for this, and then get make-up artist to add freckles and the like to match the wearers skin tones and details.
Locally, finding retailers with TPE's in stock is harder then trying to print them. They're also pretty abrasive to brass nozzles.
I keep my filaments in plastic boxes with plenty of silica gel on bottom. (dirt cheap if you buy the kitty litter quality in large bags). I have a kind of bowden style tubes for filament takeoff. I mount the selected ptfe tube close to printer and the rest of tubes loop back to a quick link connector on box. Any large enough box will do and some tubing can be mounted to hold several rolls in a row.
Food drier and/or vacuum are some methods I've used to dry other filament. After they are dry, they keep dry and print from the box.
Another underrated property of TPU is its thermal resistance against other materials. Rigid TPU 98A is my go to material for car accessories.
I never put glue stick on my print beds. Just make sure you have a properly levelled build surface. I usually print TPU on my smooth PET surface and I cannot complain about too weak or too strong bed adhesion. Same applies to my Ender 2 with stock surface and bowden setup. I lowered the print speeds drastically on the ender, btw.
Ok but others do different.
Dude i swear you need an honorary degree already! Youve done so much more science on this channel than my 3 science degrees combined !!!