For months now I have had this maddening problem where filament samples kept printing really well, but then when I bought more it kept failing. I thought polymaker was pulling a fast one in me. This explains so much.
Been printing for about 2 years now. Just finally got some tpu and 4 prints later, can't get the walls to stick. Slowed down to 20mm and temp at 210 to help with stringing. This video came in handy.
I just wanted to thank you for your TPU videos They've helped me time everything in and my TPU printing game is strong now. Nice and smooth and super glossy. TPU ROCKS!!!!!!
I'm running custom direct drive Titan extruder with stock Ender 3 hotend via about 45 mm of Bowden from the nozzle to guts of the extruder. So far low tension and a sort of flexibles no issues. It looks like that short PTFE makes no issues or just the geometry of Titan makes it running nice. And quite speedy with good surface quality. In many cases thanks to You findings!
I bought this 3D printer 2 years ago and bought the TPU 75A and I have the same problem. I bought the TPU 95 and everything is fine. I was waiting maybe for new gears or another solution. And I couldn't print the 75A. Now I realize that I may have had a problem with the filament sensor and the spool trying to spin. Thank you!
I'm thinking the same thing! We print NinjaFlex (85A) almost exclusively. Our CR-10 S5's have Microswiss direct extruders, and work well, but we decided to get more printers and went with the Creality CR-M4. Same issue as the video! We are about ready to return them, but I'm going to try some way of removing the pretension. We're looking at adding 8 printers to our farm and this may have made my life a little easier!
I made the same comment in a bit more detail and then scrolled down to see your comment about adding a drive motor to create TPU filament slack above the 3D printer's extruder. I'd considered making a filament detensioner when trying to get TPU to print properly a few years ago. I sell a TPU 3D printed product, so I have a lot of experience printing TPU. I'm surprised there isn't an aftermarket product that is mounted between the filament run out sensor and the extruder to ensure there is no tension in the TPU filament. I mostly solved that problem by hanging the filament two feet above the printer and using smooth rollers so there is very little tension in the filament when it feeds straight down into the extruder. I recently upgraded to a Neptune 4 Pro. I didn't even consider 3D printers such as the Anycubic Kobra 2 that have a reverse Bowden tube, because that's going to cause problems when printing with TPU.
Brilliant, problem solved straight away. I just spooled off a foot from the main reel and kept doing that during the print. Would have to come up with a better solution for longer prints but at least we know what we working with. Many thanks!
I believe that i just stumbled onto the solution for a problem that I unknowingly ran into just today. I'll strip tpu off the spool and retry my print to see if the problem goes away. Thank you!
Brilliant! Thank you. I print a fair amount of TPU. The easiest are Ninjatek Cheetah and Overture High Speed. For softer applications Polyflex 90A works well but I have to print much slower. After seeing this video I am looking forward to retrying the softer materials I have struggled with in the past. Thanks.
After a month of continuous tests, I have been able to successfully print in TPU 60 on my Stock* Ender 3 S1 Pro, I did change the nozzle to a Creality brand 0.8mm nozzle that was supposed to have a much smoother and more polished channel compared to the normal brass nozzles. I was now able to have consistent pressures pushing forward to print but I do need to babysit my printer to ensure I always have filament slack to reduce any possible drag. I should post a vid on my findings. Thanks for the helpful tips Lost in Tech!
I tried printing an object using Ninjaflex 85A, and got the same results you did, after successfully printing a temp tower and retraction tower. Good info and thanks! Special note, I had just taken it out of my filament dryer, probably didn't help the situation.
Im very glad i watched this. Just printing tpu 1st time on my new ender3 s1 plus. No issues yet but i didnt actually know about that tension screw, so if i do get an issue i know what im checking.
Thank you for sharing your great observations that substantially increase the community knowledge on TPU printing. I sell a product that I 3D print from TPU 98 and I'm developing a TPU 95 version. I pull a foot of TPU filament off the reel when I start a new print to prevent the extruder from stretching the filament that could cause a slight under extrusion on the critical initial layers and have the extrusion variable set to compensate for filament stretch but that's difficult to adjust because the moving print head unreels filament when at the edge of the part's print envelope (under extruding during this process) and then prints from the slack filament the rest of the time. I recently upgraded to an Elegoo Neptune 4 Pro and I'm still experimenting and learning about TPU on this new extruder. Your observations were very useful in helping me understand what's happening although I think I had a good intuitive understanding of the problematic TPU extrusion based on a few years of manufacturing experience. I'll definitely try extruder pull out tests on a couple of durometers of TPU, and I'll weigh some test cubes with TPU printed off the reel versus TPU with slack filament above the extruder. I'd previously considered building a TPU detensioner that is essentially a driven gear and sensor just below the filament run out sensor that pulls the TPU off the reel to keep constant slack in the TPU as it feeds into the extruder. It may be time to revisit that project for printing softer TPU filaments. I long ago switched to hanging the reels a couple of feet above the printers and feeding the filament directly down into the extruder. That's the only way I could get TPU to print. I can't believe people try to feed TPU through a reverse Bowden tube. I didn't even consider 3D printers with a reverse Bowden tube such as the Anycubic Kobra 2 because I print a lot of TPU.
Good stuff! I've only printed 95a TPU so far with the sprite and it prints as well as PLA in my experience. Good to note I may run into issues with the softer stuff. I appreciate the effort you put into this video.
Great explanation thank you. I was about to buy a dual gear extruder for TPU without ever testing my current ender extruder which i've converted to DD using all original hardware.
So, this week I was writing a long post for your Discord on precisely this problem. Ninja flex on a 1KG real is heavy enough but then add the most bulky spool holder of any of the filaments I’ve come across and it leads to too much tension causing problems. Strange thing is that it is not a consistent problem. My next step in solving this will be to up the tension on the Hemera but unspooling has made the most difference to my under extrusion issues so far. Thanks for another great vid.
This is an interesting dilemma, since softer filaments seem to also tend to be hydroscopic. I do a little with TPU, but more so working with PVA, I run both out of a drybox and while there are rollers in the dry box, the drag is still noticeable.
I had a similar issue and fixed it with hanging the 3KG TPU 82A roll off a rod, and greasing the inside of the roll (where it touches the rod) with vaseline. Works perfectly now. ^^
I have an old Fablicator FM1 that has a smooth bearing roller that swaps out when using TPU for this very reason. That printer has always excelled with TPU (even NinjaFlex) My Prusa's - I had to loosen the tension on the bondtech double gears, also switching to a .6mm nozzle did wonders. Prints flawless.
My Sprite was too tight for TPU, it squashed it, got caught in the extrusion gears & made an almighty mess. I stripped it down & sorted that, adjusted the gears set to minimum pressure & it happened again. This time I squashed the spring with pliers so it's about 1 to 1.5mm shorter, now the adjustment will back off so there is no pressure on the filament. I have found the best setting for me is adjust until it touches the filament & then 1/2 a turn. Prints nicely now & still has plenty of pressure adjustment for the harder filaments. My spool holder is basically an H shape with 4 bearings for the spool to sit & roll on & for now, cable tied to the gantry top.
You want to minimize any drag between the spool and extruder. In addition to making the spool spin easily, adding a reverse Bowden tube (PTFE with a 3mm inner diameter) to guide the filament to the extruder will avoid it getting snagged on something.
@@LostInTech3D I've always heard you should use 3mm ID tube for reverse bowden, to minimise friction as much as possible (given it's not actually acting as a bowden tube)
Reverse bowden tube can actually make things worse in this aspect. If you run a reverse bowden tube, you effectively make the distance between the spool and the hotend contstant. If you don't the distance changes with the print head location. This means, whenever the print head moves away from the spool, it will jerk on the fliament, releasing more filament from the spool than necessary, which loosens the tension after the jerk. Since the jerk is strong enough to overcome static friction (and it's also very short), you will have a lot less friction in the system in total. Also, a reverse bowden tube adds friction (even one with 3mm inner diameter), so if you are trying to reduce (static) friction, a reverse bowden tube is the wrong tool.
@@LostInTech3D It did :D I did a test where i would print a cylinder in vase mode, 20 layers with slacking filament, the next 20 without slack and a small weight on the spool (to simulate the filament sensor, which i had bypassed) and so on. The difference is clearly visible.
I wonder if a second extruder set up just to feed the filament from the spool would help. Better yet would be some way to measure tension on the feed filament to make sure it's always slightly slack.
I use a paint roller with bearings from the hardware store as the base for my spool holder. Maintaining a desirable level of tension for stiffer plastics is the bigger problem for that thing.
@@LostInTech3D Next time your in a hardware store, just give the green Wooster brand paint roller a feel. It's smoother than quite a few of the VXB bearing based print your own spool designs I tried when loaded and I spent less on that then the bearings. The only problem are those spools with the tiny 3/4in center holes.
I recently upgraded my Ender-3 V2 and put a Sprite Pro extruder on it. This will come in handy when I go to use the TPU I'm getting for Christmas (no idea what rating it is). Also, "put cactus here" 🤣
found out the same thing. When using flexible filament you need to manually loosen the filament off the roll. Larger rolls have higher resistance than smaller rolls. I get great results by doing this. A pain, but necessary.
I think I'll have to try the tug test with my Bondtech dual gears. I believe the spacing of the two hobbed channels is significantly closer on those than what you depict here. I've not had issues with TPU as low as 82A yet.
Love your tpu videos! you've covered the bowden worst-case, would you be interested in covering the 'new printer' worst case? Something like tpu with all metal hotend and oddly designed direct drive gearing?
I have had the same results needing to reduce resistance to get it to print using a single gear extruder. The dual gear extruder have worked better, but I have yet to test other flexible TPU materials. I have a longer LLK5 PRO for the single gear extruder, and a Sovol 4 3d printer with dual gear direct drive.
PRUSA MK3s with SaintSmart TPU. Loosening one turn the tensioner seems to work. Also bypassing the MMU2 is imperative. Fil rol on top of the extruder with the standard PRUSA trays that came with the MMU2 and have ball bearings. Slack is not necessary except when loading
Yay, the notebook is back! So does whichever printer you've used for soft TPU video have a spool holder with bearings, and no filament sensor? Wasn't it SKREnder?
I don't think so - it could be variance in the teeth, but yeah you can't achieve that, it's determined by the hardware. I suspect they are just not that well made and not perfectly round.
I mean I've been using the E3D hobb goblin on my Neptune 2 and the Bowden extruder design from Tech2c for over a year, it's one of the best TPU printers I have
Wow...I never think about this one....I´m having the same problem and stops coming out. I realise that there was something wrong with the tention on gears because incresing it was working for sometime and stops coming out again. I´m going to try removin that friction and post a coment. I´m using an Ender 5 S1 with Winkle Tenaflex maybe 90A.
here's a rough theory of the moment..... if your mainboard has an unused driver, you could add another stepper motor to the spool holder. something like adding a rubber wheel to it in the middle to turn the spool in increments. you'd have to figure out gcode to rotate the spool for every x amount of filament extruded. it'd likely look something like your screenshot of bearings in the spool holder from the vid. that should unload the tension from the filament before the extruder. not sure, but you might be able to piggy back the signal off the extruder circuit so that they both turn at the same time like a dual z. might work, might end up with a giant pile of unwound spool depending on gear ratio, wheel size and extrusion rate. let me know if you actually try it. i'm curious to see if it works.
You always need to adjust your tension depending on the material you use. With PLA / PETG it´s just not noticeble at all you will be usually fine but as you can see here TPU is a different story. Also the dual gear extruder in general is not a great solution since one of the two gears will be always out of "sync" you will always get surface inconsistency with this style of mechanism. The forces in our 3D Printers are usually very small, so for most applications a direct drive single gear extrudder with a PTFE boden tube (non all metal hotend) will be the best technical solution for PLA / PETG / TPU especially TPU though.
Obviously when there is tension in the soft TPU the diameter reduces - thus no grip. The natural “grip” you will get from rubber against a clean metal bearing should be very good as long as you can really tension that filament
I have micro swiss direc drive, it works Great with TPU. But I have the same problem with my TPU 60A. I think to build a motor on the spol to roll off filament at the same speed.
@@LostInTech3D it becomes too complicated (for me) with a motor on the spool, because the speed changes the less thread there is on the spool. I'm going to start by making a ball bearing center for the spool to see if it is enough. Otherwise, I'm thinking of trying to combine the bowden and direct drive. however, I don't know if the electronics can handle it.. I know electricity, not electronics. I just want to be able to print TPU 60A easily.
OH! PULL THE FILAMENT OFF THE SPOOL. That makes sense. Especially as I dried my Filamentum 98A in a dessicator and the filament seems to want to stick to itself and takes more effort to pull off the reel.
I think slapping a small fan on the extruder will cool down the filament a bit and make it less like hot taffee. I alsways print new cores for my spools so they sit absolutely centered on the support and roll smooth as silk.
I have noticed on my direct drive extruder when printing with 95A TPU a brand new 1kg roll has slight under extrusion defects that self corrects as the roll is used up.
Hi there all. I have recently tried the Filaflex 70A on my X1 Carbon.... with no luck . I am so glad to have seen this video. My thoughts were very much the same , so I am in the process of making a top mount spool holder with bearings , and I am swapping out the stock Bowden tube with some extra smooth tube . I have only recently got my own printer so I am not quite ready to start taking apart the head but it may happen because I have an opportunity to make some money if i can get the 70A to actually work . The 82A works ok but not show room quality and not to spec for my application. Also I am using 0.4 hardened steel hot end . I don't think that is Ideal but have been told conflicting opinions on going bigger . Have you tried the 70A on an X1 Carbon?
I have same issue. I use 3mm id bowden tube to feed filament to my direct drive extruder on my diy core XY. Decided to try TPU for the first time after printing exclusively PETG for 2 years and my TPU first try failed because of friction in bowden tube. now i have to design new spool holder to feed filament without restriction
Wow finally someone that has my exact problem! It's been months of stress and tests and i finally came to this video. The point on the sprite extruder of the s1 is that even at full tightness it doesn't grip well TPU 85A or less. I upgraded to a full metal heatbreak and i use a smooth spool holder (bypassing the filament sensor obviously) but it seems like i can't go faster than 20 mm/s and i can't push retraction over 2 mm, wich is absurd. Even with theese settings my prints are far from great. Do you suggest replacing one of the extruder gears? What is the real solution to this? Is the sprite extruder bad at printing TPU and i can't do anything about it? That would be actually funny since i bought the S1 to print TPU. If you have an answer to this please tell me 'cause i'm out of hope right now.
I thought when I saw the video start.... I wonder if he rolls it off the spool! I spent days trying to work this out on my Orbiter2 extruders using Overture TPU - on Cardboard spools. I kept getting what I thought were clogs on 2 different printers. Only by pure accident I noticed excess filament I rolled off printing just fine, then as soon as it went taught and had to pull on the spool it had under extrusion again.
I had this last year printing 70A filaflex. I solved it by using lithium grease on the stock mount. Just don't do what I did the first time and apply it with a spray. It does not aid bed adhesion.
Have you used the LGX Lite? It’s been on my Ender 3 Pro since June of this year. In DD setup it flys through 65A TPU (CoexFlex brand). Could be an interesting video!
I've been meaning to build a better spool holder, I currently have my spools in a dry box next to the printer, it's on rollers and rolls fine but the filament needs to travel through the filament detector and across the frame and that's really not ideal. When I was printing TPU I just let the spool on its side on the desk next to my printer, it basically unspooled itself without any issue. It doesn't work with PLA or PETG but I don't have issue with those, at least the issues aren't as severe. I did print a hanging filament spool holder with bearing but there's very little friction, it turns out you want a little friction because the whole spool basically ran out.
if the gears were larger diameter it would allow a larger contact patch which may well solve this issue , im obviously talking a new design from the gears out but probably a better all round unit
I would hope that you do test it (that single gear actually is better than dual gear with tpu) at some point, because you spent 2 videos ive seen inferring it.
this is exactly the results I had. I printed 95a with no issues at all.. but determined my part needed softer filament... so I movedd to 85a and started getting under extrusion. Trial and error showed that if I pulled the filament out and bypassed the filament sensor I could get good prints. Even after switching to a spool holder that had bearings, it was still a problem. The mass of the spool was enough to cause the under extrusion. Problem is that with a 12 hour print I needed to just sit there and pull out filament.. not going to happen. I am still searching for a solution, going to try a small reallly light spool on the bearing holder next.
I am noticing a similar issue with my new Top Feed system. I have recently replaced the hot end and then upgraded to a Direct feed system. I also added an all aluminum extruder to avoid some of the issues with slippage on the plastic one my original printer came with. I am running simple PLA from Overture, one of the best PLAs I can get through my machine. But the 1kg spool weighs too much for the extruder to pull the filament. The only way to get a perfect print is to pull filament off the spool. Any suggestions on how to incease the pulling power on the motor that drives the filament?
Is there any way of trying a dual motor extruder, one being the main extruder motor (situated at the extruder like a normal direct drive) and the other one just pulling filament from the roll (situated near the filament roll like a bowden one) mimicking the main extruder movement, so the tension generated by the extruder from pulling the filament is removed. In short, a printer with two motors for the extrusion system, one normal direct drive extruder and the another motor as a bowden extruder that work with exactly the same movements.
Do you think the bowden hotends print TPU better than all metal hotends? my all metal direct drive setup is having issues with friction in the hotend but a sprite bowden setup might fix that
fundamentally no, I use a fair few all metal hotends that perform adequately for 95A TPU, at much better than bowden speeds. Unless you're printing 70A then I would try to fix your metal DD, or try another heat break maybe.
@@LostInTech3D yeah I’ve been printing with Filaflex 70a, which was going somewhat smoothly. until I swapped from my stock ender 3 hotend+ a micro Swiss heatbreak and cooling block to an e3d heating block+ micro Swiss heatbreak and cooling block. I might have to swap both the heat break and the cooling block though because I can’t seam to separate them. Another weird thing I’ve encountered is that my temps need to be much higher to print since I swapped to the e3d themrisistor, but I probably just need to change the values of the thermisistor resistance table in the firmware.
Took me a few days to watch this, but very interesting. I have the regular S1 and I have super soft Ninja Flex, which doesn't print nicely, but I'll try this next time. Why bypass the runout sensor?
The runout sensor is a huge source of friction, and also hard to load. Best to bypass it, if you can't, theres an option of stuffing a piece of PLA in there.
Why is the hobb so deep? Straight edges prevents varying extrusion if filament travels between sides, but still... Can't we have compact extruder with both (all) gears driven? Like OMG but closer to LGX in size
I am now printing decent 95A TPU filament with ball bearing filament holder, ball bearing filament feeder, 30 mm/s outer layer, 3mm/s retraction, 10mm/s first layer, 220 C extruder 60 C bed my cheap/trusty good ol' Ender 3! Thank you for the knowledge 🧠
Oh, just buy it. Review will confirm that when it finally comes out, THIS WEEKEND I PROMISE! They might run out of stock so don't wait for me. Any questions, come ask me on discord.
Don't know about dumping on all dual gear extruders just because of this one. Those teeth are massively far apart at max tension. A few different designs out there that might work better than this one.
Interesting! Never have a problem with any TPU on my Prusa, And actually run less pressure on the rollers than harder filaments….as recommended by Prusa….course it isn’t Bowden tube😎
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For months now I have had this maddening problem where filament samples kept printing really well, but then when I bought more it kept failing. I thought polymaker was pulling a fast one in me. This explains so much.
Haha yes !
This video is still helping people printing TPU after a year! Thank you very much!
glad to help!
Been printing for about 2 years now. Just finally got some tpu and 4 prints later, can't get the walls to stick. Slowed down to 20mm and temp at 210 to help with stringing. This video came in handy.
I just wanted to thank you for your TPU videos They've helped me time everything in and my TPU printing game is strong now. Nice and smooth and super glossy. TPU ROCKS!!!!!!
I'm running custom direct drive Titan extruder with stock Ender 3 hotend via about 45 mm of Bowden from the nozzle to guts of the extruder. So far low tension and a sort of flexibles no issues. It looks like that short PTFE makes no issues or just the geometry of Titan makes it running nice. And quite speedy with good surface quality. In many cases thanks to You findings!
This video is AMAZING! Thanks for making it - at first sight it wouldn’t deserve such a lengthy one, but I truly enjoyed the journey 😊
Appreciate the comments 😁👍👍
I bought this 3D printer 2 years ago and bought the TPU 75A and I have the same problem. I bought the TPU 95 and everything is fine. I was waiting maybe for new gears or another solution. And I couldn't print the 75A. Now I realize that I may have had a problem with the filament sensor and the spool trying to spin. Thank you!
maybe an even more overkill solution is to have an extra stepper motor to pre pull the filament so there's a perpetual slack
I'm thinking the same thing! We print NinjaFlex (85A) almost exclusively. Our CR-10 S5's have Microswiss direct extruders, and work well, but we decided to get more printers and went with the Creality CR-M4. Same issue as the video! We are about ready to return them, but I'm going to try some way of removing the pretension. We're looking at adding 8 printers to our farm and this may have made my life a little easier!
Yeah like adding a one gear extruder behind that is plugged on the same cable and extrudes the same amount so the slack is kept the same lenght
That is exactly what I was going to say.
I made the same comment in a bit more detail and then scrolled down to see your comment about adding a drive motor to create TPU filament slack above the 3D printer's extruder. I'd considered making a filament detensioner when trying to get TPU to print properly a few years ago. I sell a TPU 3D printed product, so I have a lot of experience printing TPU. I'm surprised there isn't an aftermarket product that is mounted between the filament run out sensor and the extruder to ensure there is no tension in the TPU filament. I mostly solved that problem by hanging the filament two feet above the printer and using smooth rollers so there is very little tension in the filament when it feeds straight down into the extruder.
I recently upgraded to a Neptune 4 Pro. I didn't even consider 3D printers such as the Anycubic Kobra 2 that have a reverse Bowden tube, because that's going to cause problems when printing with TPU.
My buddy is dumping his 2 Ender-3 Pros & just got the S1. He loves his flexibles so I'm sure this vid will be helpful.
I have wanted to make a pre-feed device for some time now with my delta printers. This is giving me more reason to do it.
Brilliant, problem solved straight away. I just spooled off a foot from the main reel and kept doing that during the print. Would have to come up with a better solution for longer prints but at least we know what we working with. Many thanks!
I believe that i just stumbled onto the solution for a problem that I unknowingly ran into just today. I'll strip tpu off the spool and retry my print to see if the problem goes away. Thank you!
Brilliant! Thank you.
I print a fair amount of TPU. The easiest are Ninjatek Cheetah and Overture High Speed. For softer applications Polyflex 90A works well but I have to print much slower.
After seeing this video I am looking forward to retrying the softer materials I have struggled with in the past.
Thanks.
After a month of continuous tests, I have been able to successfully print in TPU 60 on my Stock* Ender 3 S1 Pro, I did change the nozzle to a Creality brand 0.8mm nozzle that was supposed to have a much smoother and more polished channel compared to the normal brass nozzles. I was now able to have consistent pressures pushing forward to print but I do need to babysit my printer to ensure I always have filament slack to reduce any possible drag. I should post a vid on my findings. Thanks for the helpful tips Lost in Tech!
I tried printing an object using Ninjaflex 85A, and got the same results you did, after successfully printing a temp tower and retraction tower. Good info and thanks! Special note, I had just taken it out of my filament dryer, probably didn't help the situation.
Im very glad i watched this. Just printing tpu 1st time on my new ender3 s1 plus. No issues yet but i didnt actually know about that tension screw, so if i do get an issue i know what im checking.
Add this to what we learned from MirageC and it seems that dual gear direct drive isn't the golden gun we think it is
No, it absolutely isn't! And the prusa lines problem that mihai talked about was a dual gear thing too. Boo, down with dual gear!
Decided to hop out of CNC Kitchens new video for this
😮you better hop back in after!
@@LostInTech3D conical slicing
I did the same
Both vids were at the top of my feed. I came here 1st. On my way to CNC now
I haven't got to that fir video yet, I will but might not be today. It's longer too ;)
Thank you for sharing your great observations that substantially increase the community knowledge on TPU printing. I sell a product that I 3D print from TPU 98 and I'm developing a TPU 95 version. I pull a foot of TPU filament off the reel when I start a new print to prevent the extruder from stretching the filament that could cause a slight under extrusion on the critical initial layers and have the extrusion variable set to compensate for filament stretch but that's difficult to adjust because the moving print head unreels filament when at the edge of the part's print envelope (under extruding during this process) and then prints from the slack filament the rest of the time.
I recently upgraded to an Elegoo Neptune 4 Pro and I'm still experimenting and learning about TPU on this new extruder. Your observations were very useful in helping me understand what's happening although I think I had a good intuitive understanding of the problematic TPU extrusion based on a few years of manufacturing experience. I'll definitely try extruder pull out tests on a couple of durometers of TPU, and I'll weigh some test cubes with TPU printed off the reel versus TPU with slack filament above the extruder.
I'd previously considered building a TPU detensioner that is essentially a driven gear and sensor just below the filament run out sensor that pulls the TPU off the reel to keep constant slack in the TPU as it feeds into the extruder. It may be time to revisit that project for printing softer TPU filaments.
I long ago switched to hanging the reels a couple of feet above the printers and feeding the filament directly down into the extruder. That's the only way I could get TPU to print. I can't believe people try to feed TPU through a reverse Bowden tube. I didn't even consider 3D printers with a reverse Bowden tube such as the Anycubic Kobra 2 because I print a lot of TPU.
Good stuff! I've only printed 95a TPU so far with the sprite and it prints as well as PLA in my experience. Good to note I may run into issues with the softer stuff. I appreciate the effort you put into this video.
Great explanation thank you. I was about to buy a dual gear extruder for TPU without ever testing my current ender extruder which i've converted to DD using all original hardware.
So, this week I was writing a long post for your Discord on precisely this problem. Ninja flex on a 1KG real is heavy enough but then add the most bulky spool holder of any of the filaments I’ve come across and it leads to too much tension causing problems. Strange thing is that it is not a consistent problem. My next step in solving this will be to up the tension on the Hemera but unspooling has made the most difference to my under extrusion issues so far. Thanks for another great vid.
This is an interesting dilemma, since softer filaments seem to also tend to be hydroscopic. I do a little with TPU, but more so working with PVA, I run both out of a drybox and while there are rollers in the dry box, the drag is still noticeable.
I had a similar issue and fixed it with hanging the 3KG TPU 82A roll off a rod, and greasing the inside of the roll (where it touches the rod) with vaseline. Works perfectly now. ^^
I have an old Fablicator FM1 that has a smooth bearing roller that swaps out when using TPU for this very reason. That printer has always excelled with TPU (even NinjaFlex)
My Prusa's - I had to loosen the tension on the bondtech double gears, also switching to a .6mm nozzle did wonders. Prints flawless.
Very interesting indeed. This makes me not feel so uncool for still running EZR extruders on half of my machines😁
My Sprite was too tight for TPU, it squashed it, got caught in the extrusion gears & made an almighty mess. I stripped it down & sorted that, adjusted the gears set to minimum pressure & it happened again. This time I squashed the spring with pliers so it's about 1 to 1.5mm shorter, now the adjustment will back off so there is no pressure on the filament. I have found the best setting for me is adjust until it touches the filament & then 1/2 a turn. Prints nicely now & still has plenty of pressure adjustment for the harder filaments. My spool holder is basically an H shape with 4 bearings for the spool to sit & roll on & for now, cable tied to the gantry top.
I love your videos, man. Entertaining and educational. Cheers
super helpful, thank so much for sharing this
thanks, helpful. I get this kind of under extraction on my S1 and this may be the reason.
You want to minimize any drag between the spool and extruder. In addition to making the spool spin easily, adding a reverse Bowden tube (PTFE with a 3mm inner diameter) to guide the filament to the extruder will avoid it getting snagged on something.
3mm PTFE 👀 I should test that
I picked up some reverse bowden tube from Capricorn at ERRF. It's larger inside diameter
@@LostInTech3D I've always heard you should use 3mm ID tube for reverse bowden, to minimise friction as much as possible (given it's not actually acting as a bowden tube)
Reverse bowden tube can actually make things worse in this aspect. If you run a reverse bowden tube, you effectively make the distance between the spool and the hotend contstant. If you don't the distance changes with the print head location. This means, whenever the print head moves away from the spool, it will jerk on the fliament, releasing more filament from the spool than necessary, which loosens the tension after the jerk.
Since the jerk is strong enough to overcome static friction (and it's also very short), you will have a lot less friction in the system in total.
Also, a reverse bowden tube adds friction (even one with 3mm inner diameter), so if you are trying to reduce (static) friction, a reverse bowden tube is the wrong tool.
Omg thank you!
I also have an Ender 3S1 and i've noticed that exact problem with 85A TPU. I'll try that right away :D
Good luck, I'm sure it will work!
@@LostInTech3D It did :D
I did a test where i would print a cylinder in vase mode, 20 layers with slacking filament, the next 20 without slack and a small weight on the spool (to simulate the filament sensor, which i had bypassed) and so on. The difference is clearly visible.
I wonder if a second extruder set up just to feed the filament from the spool would help. Better yet would be some way to measure tension on the feed filament to make sure it's always slightly slack.
That's actually a fascinating idea
I use a paint roller with bearings from the hardware store as the base for my spool holder. Maintaining a desirable level of tension for stiffer plastics is the bigger problem for that thing.
That's a good solution!
@@LostInTech3D Next time your in a hardware store, just give the green Wooster brand paint roller a feel. It's smoother than quite a few of the VXB bearing based print your own spool designs I tried when loaded and I spent less on that then the bearings. The only problem are those spools with the tiny 3/4in center holes.
I recently upgraded my Ender-3 V2 and put a Sprite Pro extruder on it. This will come in handy when I go to use the TPU I'm getting for Christmas (no idea what rating it is).
Also, "put cactus here" 🤣
Also if you have tension before the extruder, wouldn't you will be pulling through material that is less than 1.75mm because it will be stretched
yes I mentioned that, and absolutely the case 👍
Very good ser!
found out the same thing. When using flexible filament you need to manually loosen the filament off the roll. Larger rolls have higher resistance than smaller rolls. I get great results by doing this. A pain, but necessary.
I think I'll have to try the tug test with my Bondtech dual gears. I believe the spacing of the two hobbed channels is significantly closer on those than what you depict here. I've not had issues with TPU as low as 82A yet.
Could the roll spin on really good bearings to lower the resistance? Using opposing magnets might be cool to totally remove the resistance.
Thank you.
Love your tpu videos! you've covered the bowden worst-case, would you be interested in covering the 'new printer' worst case? Something like tpu with all metal hotend and oddly designed direct drive gearing?
I have had the same results needing to reduce resistance to get it to print using a single gear extruder. The dual gear extruder have worked better, but I have yet to test other flexible TPU materials. I have a longer LLK5 PRO for the single gear extruder, and a Sovol 4 3d printer with dual gear direct drive.
PRUSA MK3s with SaintSmart TPU. Loosening one turn the tensioner seems to work. Also bypassing the MMU2 is imperative. Fil rol on top of the extruder with the standard PRUSA trays that came with the MMU2 and have ball bearings. Slack is not necessary except when loading
Concave feeder gears are the best imo. better grip overall
Yay, the notebook is back!
So does whichever printer you've used for soft TPU video have a spool holder with bearings, and no filament sensor? Wasn't it SKREnder?
skrender has the holder right above, but it was nowhere near as neat as this, I previously didnt think you could FDM 70A this neatly
At 8:54 in the video, you can see that the wheels are closer together.
How did you achieve this?
I don't think so - it could be variance in the teeth, but yeah you can't achieve that, it's determined by the hardware. I suspect they are just not that well made and not perfectly round.
3:07 surely that the minimum spacing not the maximum. It would be the maximum grab.
I mean I've been using the E3D hobb goblin on my Neptune 2 and the Bowden extruder design from Tech2c for over a year, it's one of the best TPU printers I have
that's a good name for an extruder, I get the reference haha
@@LostInTech3D actually the hobb goblin is just the drive gear, they're about a fiver mate, go get one :P
I'll buy anything from E3D that's only a fiver!😂
Wow...I never think about this one....I´m having the same problem and stops coming out. I realise that there was something wrong with the tention on gears because incresing it was working for sometime and stops coming out again. I´m going to try removin that friction and post a coment.
I´m using an Ender 5 S1 with Winkle Tenaflex maybe 90A.
Thank you. Yes, it works with your solution.
here's a rough theory of the moment..... if your mainboard has an unused driver, you could add another stepper motor to the spool holder. something like adding a rubber wheel to it in the middle to turn the spool in increments. you'd have to figure out gcode to rotate the spool for every x amount of filament extruded. it'd likely look something like your screenshot of bearings in the spool holder from the vid. that should unload the tension from the filament before the extruder.
not sure, but you might be able to piggy back the signal off the extruder circuit so that they both turn at the same time like a dual z. might work, might end up with a giant pile of unwound spool depending on gear ratio, wheel size and extrusion rate. let me know if you actually try it. i'm curious to see if it works.
If the spool can still move with friction instead of being directly connected to the motor, you could probably get away with it moving more slowly.
Or you could just add another tensioner/motor on the filament at the top.
You always need to adjust your tension depending on the material you use. With PLA / PETG it´s just not noticeble at all you will be usually fine but as you can see here TPU is a different story.
Also the dual gear extruder in general is not a great solution since one of the two gears will be always out of "sync" you will always get surface inconsistency with this style of mechanism.
The forces in our 3D Printers are usually very small, so for most applications a direct drive single gear extrudder with a PTFE boden tube (non all metal hotend) will be the best technical solution for PLA / PETG / TPU especially TPU though.
Obviously when there is tension in the soft TPU the diameter reduces - thus no grip. The natural “grip” you will get from rubber against a clean metal bearing should be very good as long as you can really tension that filament
Have you tried the Omniadrop Extruder for printing flexibles? In my opinion, it beats every other extruder out there!
I saw it at TCT but I've not got my hands on one yet
@@LostInTech3D Get in touch with Max from Dropeffect. It's definitely a blast printing with one of them!
That thing looks awesome, thx for the heads up!
I have micro swiss direc drive, it works Great with TPU. But I have the same problem with my TPU 60A. I think to build a motor on the spol to roll off filament at the same speed.
That would be really interesting, I hope if you get anywhere with it you keep me updated!
@@LostInTech3D
it becomes too complicated (for me) with a motor on the spool, because the speed changes the less thread there is on the spool. I'm going to start by making a ball bearing center for the spool to see if it is enough. Otherwise, I'm thinking of trying to combine the bowden and direct drive. however, I don't know if the electronics can handle it.. I know electricity, not electronics. I just want to be able to print TPU 60A easily.
OH! PULL THE FILAMENT OFF THE SPOOL.
That makes sense. Especially as I dried my Filamentum 98A in a dessicator and the filament seems to want to stick to itself and takes more effort to pull off the reel.
I think slapping a small fan on the extruder will cool down the filament a bit and make it less like hot taffee. I alsways print new cores for my spools so they sit absolutely centered on the support and roll smooth as silk.
Thats why I like the old Titan Extruder 🙂
The real (or accurate clone) one with hobbed gear and stupid arm or clone with straight gear and arm with bearing?
Actually, the Anycubic Clone was or is really good. Even on a large Delta i was able to print TPU 👍😊.
I have noticed on my direct drive extruder when printing with 95A TPU a brand new 1kg roll has slight under extrusion defects that self corrects as the roll is used up.
For any tpu you need filament support with some bearing, even for 95A
Hi there all. I have recently tried the Filaflex 70A on my X1 Carbon.... with no luck . I am so glad to have seen this video. My thoughts were very much the same , so I am in the process of making a top mount spool holder with bearings , and I am swapping out the stock Bowden tube with some extra smooth tube . I have only recently got my own printer so I am not quite ready to start taking apart the head but it may happen because I have an opportunity to make some money if i can get the 70A to actually work . The 82A works ok but not show room quality and not to spec for my application. Also I am using 0.4 hardened steel hot end . I don't think that is Ideal but have been told conflicting opinions on going bigger . Have you tried the 70A on an X1 Carbon?
"Also what I'm saying here is entirely irrelevant for subtitles. How about this instead: 🐇." Hahaha welcome to the Matrix, man!
Off topic, how to you like the screw driver? I was concerned it would not have enough torque... you seem to use it with no issues. Recommend?
it's more of an assisted driver than doing the work itself, you can drive and turn it. It's _okay_
I have same issue. I use 3mm id bowden tube to feed filament to my direct drive extruder on my diy core XY. Decided to try TPU for the first time after printing exclusively PETG for 2 years and my TPU first try failed because of friction in bowden tube. now i have to design new spool holder to feed filament without restriction
Wow finally someone that has my exact problem! It's been months of stress and tests and i finally came to this video. The point on the sprite extruder of the s1 is that even at full tightness it doesn't grip well TPU 85A or less. I upgraded to a full metal heatbreak and i use a smooth spool holder (bypassing the filament sensor obviously) but it seems like i can't go faster than 20 mm/s and i can't push retraction over 2 mm, wich is absurd. Even with theese settings my prints are far from great. Do you suggest replacing one of the extruder gears? What is the real solution to this? Is the sprite extruder bad at printing TPU and i can't do anything about it? That would be actually funny since i bought the S1 to print TPU. If you have an answer to this please tell me 'cause i'm out of hope right now.
I thought when I saw the video start.... I wonder if he rolls it off the spool!
I spent days trying to work this out on my Orbiter2 extruders using Overture TPU - on Cardboard spools. I kept getting what I thought were clogs on 2 different printers. Only by pure accident I noticed excess filament I rolled off printing just fine, then as soon as it went taught and had to pull on the spool it had under extrusion again.
Hey! Thank you for the very detailed information exept for one: Which filament did you use exactly?! Link would be much appreciated ;)
Oh - haha, it's recreus filaflex 70A.
I had this last year printing 70A filaflex. I solved it by using lithium grease on the stock mount. Just don't do what I did the first time and apply it with a spray. It does not aid bed adhesion.
Hahaha no, greasing the bed is probably not good 😂
Have you used the LGX Lite? It’s been on my Ender 3 Pro since June of this year. In DD setup it flys through 65A TPU (CoexFlex brand). Could be an interesting video!
I've been meaning to build a better spool holder, I currently have my spools in a dry box next to the printer, it's on rollers and rolls fine but the filament needs to travel through the filament detector and across the frame and that's really not ideal. When I was printing TPU I just let the spool on its side on the desk next to my printer, it basically unspooled itself without any issue. It doesn't work with PLA or PETG but I don't have issue with those, at least the issues aren't as severe. I did print a hanging filament spool holder with bearing but there's very little friction, it turns out you want a little friction because the whole spool basically ran out.
THANKS SOLVED ON SPRITE PRO NEW SUB
if the gears were larger diameter it would allow a larger contact patch which may well solve this issue , im obviously talking a new design from the gears out but probably a better all round unit
I unwind 1kg spools onto empty spools with 200g filament on them. Seems to help.
What brand TPU are you using? And have you tried printing the 70A on Bowden?
See the video before this one 👍
What's with the rectangle drawn around the print ? Seems superfluous
It's to purge the nozzle
@@LostInTech3D oh right, my printer just does a single line out of the way
I would hope that you do test it (that single gear actually is better than dual gear with tpu) at some point, because you spent 2 videos ive seen inferring it.
this is exactly the results I had. I printed 95a with no issues at all.. but determined my part needed softer filament... so I movedd to 85a and started getting under extrusion. Trial and error showed that if I pulled the filament out and bypassed the filament sensor I could get good prints. Even after switching to a spool holder that had bearings, it was still a problem. The mass of the spool was enough to cause the under extrusion. Problem is that with a 12 hour print I needed to just sit there and pull out filament.. not going to happen.
I am still searching for a solution, going to try a small reallly light spool on the bearing holder next.
I am noticing a similar issue with my new Top Feed system. I have recently replaced the hot end and then upgraded to a Direct feed system. I also added an all aluminum extruder to avoid some of the issues with slippage on the plastic one my original printer came with.
I am running simple PLA from Overture, one of the best PLAs I can get through my machine. But the 1kg spool weighs too much for the extruder to pull the filament. The only way to get a perfect print is to pull filament off the spool.
Any suggestions on how to incease the pulling power on the motor that drives the filament?
you could try a spool holder with bearings in it, if you aren't already.
@@LostInTech3D Awesome! Thanks for the quick reply.
genius sir
Is there any way of trying a dual motor extruder, one being the main extruder motor (situated at the extruder like a normal direct drive) and the other one just pulling filament from the roll (situated near the filament roll like a bowden one) mimicking the main extruder movement, so the tension generated by the extruder from pulling the filament is removed. In short, a printer with two motors for the extrusion system, one normal direct drive extruder and the another motor as a bowden extruder that work with exactly the same movements.
yes - it should work in fact, perhaps with some attention to how to allow it to slip if it doesnt sync exactly
I suspect that MK8 and Wade geared/belted variants are the best extruders ever created and I don't know how we got where we got.
Do you think the bowden hotends print TPU better than all metal hotends? my all metal direct drive setup is having issues with friction in the hotend but a sprite bowden setup might fix that
fundamentally no, I use a fair few all metal hotends that perform adequately for 95A TPU, at much better than bowden speeds. Unless you're printing 70A then I would try to fix your metal DD, or try another heat break maybe.
@@LostInTech3D yeah I’ve been printing with Filaflex 70a, which was going somewhat smoothly. until I swapped from my stock ender 3 hotend+ a micro Swiss heatbreak and cooling block to an e3d heating block+ micro Swiss heatbreak and cooling block. I might have to swap both the heat break and the cooling block though because I can’t seam to separate them. Another weird thing I’ve encountered is that my temps need to be much higher to print since I swapped to the e3d themrisistor, but I probably just need to change the values of the thermisistor resistance table in the firmware.
Took me a few days to watch this, but very interesting. I have the regular S1 and I have super soft Ninja Flex, which doesn't print nicely, but I'll try this next time. Why bypass the runout sensor?
The runout sensor is a huge source of friction, and also hard to load. Best to bypass it, if you can't, theres an option of stuffing a piece of PLA in there.
How would you say the Sprite compares to the Microswiss NG?
I've not used it, opinions seem mixed on microswiss
Have been printing a bunch with 85A TPU on my Ender S1 without problems.
what are your settings? i'm having a real hard time
@@FedericoPorta super slow, 0% fan
I wonder if this is why the Flexion was soo good for flexible filaments.
If i want to bypass the filament sensor you can just put a piece of filament in there so its always giving off a blue light
Yep
I had this issue with pla, but sure its dirty inside the extruder
Why is the hobb so deep? Straight edges prevents varying extrusion if filament travels between sides, but still...
Can't we have compact extruder with both (all) gears driven? Like OMG but closer to LGX in size
I am now printing decent 95A TPU filament with ball bearing filament holder, ball bearing filament feeder, 30 mm/s outer layer, 3mm/s retraction, 10mm/s first layer, 220 C extruder 60 C bed my cheap/trusty good ol' Ender 3! Thank you for the knowledge 🧠
Bondtech lgx ff. G10 build plate. Tpu perfection....
Does anyone know gow to print tpu on entina2 printer
he might have different definitions of simple in mind 😂
do the single gear dd extruder video! do the single gear dd extruder video!
I did 75a with a ender 3 neo max and got a wolverine cowl at 102% in 11 days .04 nozzle I couldn't di 95a it kept messing up. Just a Capricorn.
Give us the NEPTUNE 3 PRO review pleeaseee
im waiting with my finger on the trigger
Oh, just buy it. Review will confirm that when it finally comes out, THIS WEEKEND I PROMISE! They might run out of stock so don't wait for me. Any questions, come ask me on discord.
@@LostInTech3D You've got a point about the stock, especially with elegoo
no pressure, obviously hahaha
@@LostInTech3D btw love your style of vids and humor, never stop improving!
PS: Got my anet a6 7 goggly eyes aswell, its an biblically accurate angel
Put sunrise extruder and all you're problems will fade
Tpu sucks up moisture like a sponge. Key is to keep it dry.
Don't know about dumping on all dual gear extruders just because of this one. Those teeth are massively far apart at max tension. A few different designs out there that might work better than this one.
No doubt, but all the extruders I tried suffered to some extent.
If you think about it, the problem is intrinsic to the design.
the subtitles not matching the actual video content is incredibly annoying
The major take away here: Spreadsheets are creepy.
Interesting!
Never have a problem with any TPU on my Prusa, And actually run less pressure on the rollers than harder filaments….as recommended by Prusa….course it isn’t Bowden tube😎
Have you printed 70A TPU on it though? :)