TPU Filament Getting Jammed - Page 1
Forum section: electronics / general

author: bostonman
author_rank: Super Contributor
timestamp: July 07, 2024, 11:08:04 pm
content: Has anyone experienced TPU filament getting jammed?Months ago when I figure purchased this roll, I printed some test stuff at 0.3mm layer height (0.35mm first layer height).Today I tried printing something at 0.15mm layer height, 210 degrees C at first, and then 220 degrees C after. After three or four attempts, the TPU was coming out of the side of the nozzle housing (Anet A8).Initially I thought 210 degrees C was too cold and causing it to seize in the nozzle, so I increased it to 220. After I thought the roll wasn't spinning easy enough and causing too much resistance, so I unrolled slack.My guess is the 0.15mm layer height is causing the filament to bunch up inside the nozzle since I didn't seem to have issues with printing a 0.3mm.Has anyone experienced this issue and how should I resolve it?

author: Whales
author_rank: Super Contributor
timestamp: July 07, 2024, 11:47:26 pm
content: Yes. On my cheap printer TPU filament starts coming out of the extruder sideways if too much extrusion force is needed to get it through the nozzle.A better extruder design is the most effective solution. My design is borderline, it works IF I put the temperature up a bit higher, print slower and make sure the first layer has a big gap between nozzle and bed.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: July 07, 2024, 11:58:41 pm
content: I have also encountered TPU jamming under unusual circumstances. A glitch on the power line caused the print to stop. With the fans not running the heat soaked back up the filament path and softened the filament. I did not realize the heat soak issue a restarted the print. The filament retracted and kinked inside the direct drive extruder. Any similar issues might cause a similar issue.

author: MarkF
author_rank: Super Contributor
timestamp: July 08, 2024, 12:19:54 am
content: I've not printed TPU. But, I've seen where the gap between the extruder gear and the hotend is too big and the flexible TPU squishes out. There are various ways to try to fix this. Take a look at this video to see what I'm talking about.https://youtu.be/6kZkxkSRndM?t=170Every brand of TPU will act differently. What brand are you using?For temperatures, I usually start with values in the middle of the manufacture's recommendations.Do you know what the hardness is of the TPU that you are using?See...https://youtu.be/iWZw7RO2Sks?t=168

author: bostonman
author_rank: Super Contributor
timestamp: July 08, 2024, 02:04:21 am
content: MarkF,Just an FYI, I was trying to print the Agilent knob you created for me. My goal was to see if it would be hard enough that it can't be squeezed, but have the subtle rubber grip as the original.I'll check the filament brand and stuff later.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: July 08, 2024, 02:46:16 am
content: TPU is prone to moisture ingress. If your spool was not humidity controlled, the moisture could boil off inside the extruder and result in jams.

author: MarkF
author_rank: Super Contributor
timestamp: July 08, 2024, 11:07:28 am
content: Quote from: bostonman on July 08, 2024, 02:04:21 amThat's what I suspected.Overall, I believe TPU will be too soft and flexible for a knob.That's why I asked about the TPU hardness you're using. A different brand may be desirable.In the first video, he made a print at 235oC.The print turned out to be harder and less shiny. Both desired characteristics in this case.A high percentage of infill should make it harder also.Try a print 5oor 10ohotter to see what you get.If you look close at the bottom edge of your knob, it looks like it's made in two piece.A hard inner core, wrapped with a soft cover.However, printing a hollow soft outer cover for a knob would be problematic.

author: bostonman
author_rank: Super Contributor
timestamp: July 08, 2024, 01:22:58 pm
content: This is the stuff I bought (description directly form Amazon):GIANTARM TPU Filament, 95A TPU Filament 1.75mm, Dimensional Accuracy +/- 0.03, Flexible Soft 3D Printer Filament 1kg Spool(2.2 lbs), Vacuum Packaging (Clear)

author: MarkF
author_rank: Super Contributor
timestamp: July 08, 2024, 01:45:47 pm
content: The 'shore hardness' of 95A is what I was curious about.It will be interesting to see how you make out.Amazon has TPU with a 98A shore hardness if your knob ends up being too soft.

author: jm_araujo
author_rank: Regular Contributor
timestamp: July 08, 2024, 01:46:57 pm
content: Not knowing your slicer, are you using a TPU profile and/or did you change the speeds?I don't have much experience with TPU, but when I tried it I found that in my old printer (bowden extruder noname chinese) I had to slow everything down by at least 50%, or else something will fail.

author: bostonman
author_rank: Super Contributor
timestamp: July 08, 2024, 02:07:47 pm
content: QuoteMaybe that's another problem. I never play with any of the settings, usually I just change infill, temp, bed temp (220 for extruder and 50 on the bed for TPU), and layer heights. Edit my slicing software doesn't have a TPU setting or PLA setting.Since this is a small knob, maybe the filament is being fed too fast and jamming where as before the gasket I downloaded to do a test print was larger, so the head was moving faster.Due to reducing layer height to 0.15 and the knob being small, it's possible feed speed is the issue. I don't know for sure, but it seems the failure occurs around the same height in all three cases.

author: MarkF
author_rank: Super Contributor
timestamp: July 08, 2024, 03:06:32 pm
content: From the Amazon page for the GIANTARM TPU:Temperature: 195 - 230oCBed Temperature: 40 ~ 60oCPrint Speed: 30 ~ 45mm/sLayer Height: >= 0.25mmNozzle: >= 0.5mmYou might want to try:230oC temp, 50oC bed, 30mm/s speed, and 0.20mm layer (or 0.16mm)At least knock off 10mm/s from each speed value in your slicer

author: abeyer
author_rank: Frequent Contributor
timestamp: July 08, 2024, 07:08:23 pm
content: Quote from: MarkF on July 08, 2024, 11:07:28 amI haven't had a chance to try it yet... but I have access to a prusaxl with multiple print heads now, and want to experiment doing some multi-material knobs and buttons with both a rigid structure in petg/pla/etc and a tpu surface as a monolithic print. Seems like that could be the best of both worlds and give a result similar to the overmolding processes often used to produce that type of thing commercially.

author: bostonman
author_rank: Super Contributor
timestamp: July 09, 2024, 01:31:57 pm
content: Nozzle and bed temperatures were basically already set to those values because I saw that on Amazon and/or the spool tag. Initially I may have accidentally ran at 200 degrees C the first time it jammed, but then changed it to 220 and then 225 based off your advice (although you said 230). Bed temperature has been at 50 too and the nozzle setting is a default 0.4mm. I'm uncertain if my nozzle is 0.4 or 0.5, but I've never tinkered with this setting since I never had clogging issues until now.Also, I had tinkered with layer height by decreasing it to 0.15, but changed it to to your recommended 0.25mm.Unfortunately it jammed again with basically all the settings suggested, this time at maybe a layer or two higher than before, but still jammed.When I pull out the filament, after it unwinds from looping to the outside, it makes sort of a suction sound leading me to believe it's feeding too slow and getting bunched up inside the nozzle.Ignoring that I doubt printing a knob with TPU will be ideal (I think you're correct MarkF, it will be too soft), the part may be too small so the retracting is causing the end to curl and/or it's getting curled due to sitting in the nozzle for long periods while the head prints the small sections of the knob.Attached are the default values of my slicer. It's unclear which is the "print speed", but maybe the one I tweaked to 30mm/s was incorrect.MarkF, on a side note, I didn't realize TPU came in different shore ratings. Buying the TPU filament was a spur of the moment decision to tinker with different material, so I didn't investigate at all. It does seem the knob either has a rubber overlay or was dipped in something (good eye). After looking closer, the main section is hard plastic and then I see a small line indicating different material. So a fully printed TPU knob may not be similar unless, as you suggested, I go with a 98A, but then I'm diving into buying approx. $20 spools to experiment with printing a knob.

author: Ian.M
author_rank: Super Contributor
timestamp: July 09, 2024, 02:02:06 pm
content: How close is your extruder's throat tube to the extruder gear and pinch bearing? For flexible filaments, there should only be just enough clearance for the gear to turn freely and the pinch bearing not to contact the throat tube with no filament present. See:https://youtu.be/B71GGLBrQDU?t=82

author: MarkF
author_rank: Super Contributor
timestamp: July 09, 2024, 02:13:55 pm
content: First, have you done anything to eliminate the gap between the extruder gear and the hotend as described in that first video I posted? This insures that the soft TPU is pushed into the hotend and doesn't bend away.Before and after screenshots from video:On the speeds, there are more than just one speed. A slicer normally has multiple speeds depending on what it is doing at a particular time. For instance, one for traveling (just moving the head), one for printing a perimeter, another for printing in-fill, etc. Here are my PrusaSlicer settings for normal PLA:In this case for a knob I printed for my model railroad throttle.You are already printing much faster than I print for PLA. I can't push PLA to those speeds with my Creality CR-10.I would suggest knocking down all of the speeds in the 'Speed for print moves' section.Start by limiting the speeds to 30mm/s.Most printers come with a 0.4mm nozzle. So, unless you changed it?

author: jm_araujo
author_rank: Regular Contributor
timestamp: July 09, 2024, 02:16:25 pm
content: Try halving all the speeds. In your settings they are "Perimeters" (set to 30), "Infill" (set to 40) and "Bridges" (set to 30).You could leave as is "Supports" (which you probably are not using), and "First Layer speed" as you said you didn't have problems in the first layers.

author: MarkF
author_rank: Super Contributor
timestamp: July 09, 2024, 02:27:47 pm
content: And, I suggested pushing the high end of the temperature range because the video said the higher print temperature made the print harder. So, high temperature and a lot of infill to make you knob harder. You are NOT looking for the typical soft flexible TPU print use case here.

author: bostonman
author_rank: Super Contributor
timestamp: July 10, 2024, 12:43:04 am
content: QuoteI first wanted to rule out print settings before dismantling and making mechanical adjustments. Unfortunately those settings didn't work either, so it's off to figure out the gap.MarkF,This time I got a bit more of the knob printed; not much more but more. Using 230 degrees C either made it stiffer or due to getting more physically printed. The shaft hole doesn't seem to have the same resolution as PLA, but, due to it stretching, might fit. I was thinking, would it be possible to make the inside more hollow like the original knob and then I can fill it with two-part epoxy?This way the outside will be rubber, but it can't be squeezed due to the hard epoxy.Just a thought. You've already done quite a bit helping with two knobs, so I'm grateful to have the solution in place (i.e. you helping with the design and living in a world with 3D printers).

author: MarkF
author_rank: Super Contributor
timestamp: July 10, 2024, 01:19:55 am
content: Quote from: bostonman on July 10, 2024, 12:43:04 amNot sure I understand what you want.In your slicer (at least in the PrusaSlicer and Cura slicers) you can use a 'grid' infill and set the number of bottom layers to zero.The higher hotend temperature will make it easier to push the filament threw.Don't forget to go to theThingiverse linkin the video and printout that filler part before tearing apart your printer.

author: bostonman
author_rank: Super Contributor
timestamp: July 10, 2024, 01:54:03 am
content: The STL you provided shows a solid (see attached) inside in the 3D view.I set infill to 80% to make it harder, but, since the 3D model view showed a solid, I thought you just made it solid all the way through to save time and didn't pay attention to the possibility of it being more hollow.My slicer software gives the option of how many top and bottom layers to make solid. I set the bottom to 0, and, if it doesn't cause the software to crash, allows me to do as you stated.If I print it as you suggested, this may be a pretty cool knob providing I can get some two-part epoxy inside to stiffen it. Maybe I'll invest in a spool of gray TPU, and, with some tweaking, may not even notice the knob isn't original.Update: hopefully I'm not too late updating my post. I'll gladly print that filler part, but will it melt/bend/warp sitting in the hot end area that's 230 degrees C?

author: MarkF
author_rank: Super Contributor
timestamp: July 10, 2024, 02:12:39 am
content: FreeCAD and other 3D modelling software produce a solid object unless you've carved out interior holes.Your slicer settings determines how the inside is printed. (i.e. the interior pattern and percent of fill)Through the slicer you can make it hollow, solid, or something in between.I have a bowden tube setup on my CR-10.If I understand the Anet, you should have the extruder drive gear -> heatbreak -> hotend (heating element) -> nozzle.That part goes in the drive gear mechanism, before the heatbreak. It should never get hot unless your fan fails.

author: MarkF
author_rank: Super Contributor
timestamp: July 10, 2024, 02:44:32 am
content: Here is the modification on a bowden setup:Notice how the point of the modified part (highlighted in red) goes right in between the gear and the idler preventing the TPU from escaping from being pushed into the hotend. The Anet mod only has the triangle wedge. The filament is then fed into the hotend and nozzle. It should never get hot.

author: bostonman
author_rank: Super Contributor
timestamp: July 23, 2024, 02:27:43 am
content: QuoteThanks for the feedback.Others have provided similar feedback and the current most likely solution is to dismantle the head, check the spacing, and install a 3D printed TPU guide. This suggestion makes perfect sense because if the feed gear (?) is too far from the nozzle, the TPU will begin curling. Reducing the space seems the most likely solution.Unfortunately I've been over my head in projects and haven't had a chance to return to the printer. Long story short, this issue began because I'm printing a replacement knob with TPU for a recently repaired oscilloscope. Due to some issues, I've been elbows deep with trying to get the scope reassembled; thus delaying the need for the knob. Thankfully the scope is fully reassembled, needs to do some self calibration and tests, but soon I can divert my attention to the printer.Also, the 3D TPU Guide part is suggested to print in ABS. I have a roll, however, I haven't opened it yet nor have experience with ABS.

author: bostonman
author_rank: Super Contributor
timestamp: August 11, 2024, 02:24:57 pm
content: That filament guide was recommended to be printed with ABS. Due to never printing with ABS, it was a complete failure as I didn't investigate bed temperature and adhesive (I just went with extruder temp settings listed on the filament spool).I quickly noticed the part wasn't sticking to the bed, so I stopped. Also, the part came in different sizes and I didn't know which I'd need. My plan was to print all of them and figure it out once I dismantled the printer.Since my printer has needed major attention, I decided to just dive into it and figure out adding the filament guide later.Everyone was correct, the distance was too far. Trying to figure out how to get the hollow screw closer without hitting the gear isn't easy on this printer.Currently I'm wiring in a new heater and thermocouple as the old block had gunk all over it. The heater wasn't tight in the block, so chances are it wasn't conducting heat efficiently. Also, I realized my nozzle is 0.4mm but I've been using the default 0.5mm in the slicing software (or maybe I accidentally changed it at one time).Not sure if setting the nozzle to 0.5 instead of 0.4 would affect prints.I still need to fix the bed rails as I remember lots of tension existed for some reason.

author: MarkF
author_rank: Super Contributor
timestamp: August 11, 2024, 05:16:48 pm
content: QuoteI don't know if you are aware that ABS is toxic. Be careful to check your ventilation if you print a lot of it.QuoteI haven't been able to find a clear closeup picture of your extruder gear and I didn't download your filler part. On my Creality CR-10, the new filament guide has a short piece of PTFE tubing is trimmed into a V point to fit close to the gear. I think yours is different. I don't know how close it needs to be.QuoteMore important, a loose nozzle is more likely to cause layer shifts and might cause jamming inside the filament path through the hotend. Temperature wouldn't be my first concern. You are actually trying toblockheat transfer from the heater and nozzle getting up into the printer.QuoteI'm thinking it's probably over extruding filament unless you calibrated the error out through the e-steps/mm.I would think it would also introduce errors in the xy position.

author: bostonman
author_rank: Super Contributor
timestamp: August 12, 2024, 01:26:53 am
content: I didn't know ABS was toxic. Does a typical soldering iron air cleaner work or does the ABS need to be vented outside?The extruder wasn't loose, it was the heater that goes into the block.Attached is the spacing in the extruder before I changed the height.

author: MarkF
author_rank: Super Contributor
timestamp: August 12, 2024, 08:54:54 am
content: Another thing I forgot to mention is that ABS is susceptible to air drafts while printing.Also be aware that bed temperatures above 80oC will destroy the magnetism of those flexible bed plates!To start, I think I'll just point you to two resources to checkout.First, this short write-up gives a good overview:https://all3dp.com/2/printing-with-abs-tips-tricks/Second, this video:

author: janoc
author_rank: Super Contributor
timestamp: August 12, 2024, 09:09:35 am
content: There is this video from CNC Kitchen on printing flexibles:https://youtu.be/4InFd5DoZa4Quote from: bostonman on August 12, 2024, 01:26:53 amABS isn't toxic. Or rather - it is not toxic in the sense that you would keel over if you print it.It is not healthy though - heated ABS releases styrene, fine particles and few other things being released while printing (anyone who ever printed ABS will recognize the smell) - could cause asthma over time and similar issues. Most 3D printing filaments release similar fumes and particulates to some degree - even PETG, PLA or Nylon.So you will want to ventilate the room and ideally don't have it next to you when it is printing. But unless you are running a printing farm blasting out ABS parts 24/7 in a warehouse somewhere, you don't need to worry too much about ABS. The resins used by resin printers are waaay worse for your health than any ABS emissions you can get.However, do protect the machine itself from drafts! Certainly don't run a fan/forced ventilation there - that will cause air currents around the print, uneven cooling which makes the plastic warp and you get lifted corners, delaminated layers (with loud cracks as the part cools), etc, especially if you are don't have an enclosed machine.If you operate the printer in an enclosure then that will pretty much keep the particulates and any styrene emissions from ABS printing down as well.

author: MarkF
author_rank: Super Contributor
timestamp: August 12, 2024, 09:19:48 am
content: As for the four different STL files in the Thingiverse download, it appears the only difference is the depth of the pocket where the filament goes through. You can probably estimate the minimum pocket depth you need to make the part fit flush on top of the hotend mount.

author: bostonman
author_rank: Super Contributor
timestamp: August 13, 2024, 01:54:14 am
content: I overhauled my printer.The heater block and nozzle had gunk all over it from the previous owner, so I replaced it with a new one. As mentioned, the heater itself wasn't tight in the block so chances are it had poor thermal conductivity, and that got replaced with a new one (including the thermocouple).The hollow screw was far from the roller and gear, so I moved those closer. Most of the screws on the frame were loose and needed to be re-tightened.The wire routing wasn't to my liking, so I rerouted the wires, zip tied them, etc... to make it much prettier.The remaining item is calibrating the printer and maybe finding something better for the bed other than using painters tape over glass. Often times the painters tape rips and I need to replace it, plus removing PLA printed items is challenging at times.I printed the knob that I had been trying to print with TPU and this time the filament didn't buckle at all and the knob printed fully. Unfortunately I don't remember the settings I used for this G Code file, but I need to tweak things anyway.I'm uncertain if I'll use the filament guide (still need to tackle printing with ABS). Seems this guide would make feeding new filament difficult without dissembling the head and reassembling the head is a pain; not to mention I fear the servo mounting holes will strip soon from screwing and unscrewing.Either way, at least I've somewhat solved the TPU jamming issue. It's a matter of the distance in the head and possibly needing the filament guide. So everyone was correct regarding checking the distance.

author: MarkF
author_rank: Super Contributor
timestamp: August 13, 2024, 09:36:31 am
content: I also print on glass with my CR-10.You might want to try hairspray instead of painters tape.I can get many prints before needed to clean it off and re-applying.I do add a little extra spray between cleanings to places that I print over and over.(Like many small parts printed at the center.)I mostly print PLA and PETG and print remove is easy if I let the bed cool to room temperature.I tend to be impatient and pry the little devils off with a putty knife that came with the printer.Careful, hard prying will mess up the bed leveling.With all your changes, you might want to re-run all the steps/mm values for all axis and extruder.I replaced my brass extruder gear with a steel one and it significantly changed the required e-steps value.Especially with your mix up with the nozzle size.There should be some videos I linked to showing the process.

author: bostonman
author_rank: Super Contributor
timestamp: September 15, 2024, 01:52:29 pm
content: If anyone remembers, I moved the nozzle screw to reduce the space, but never printed the piece recommended (I had issues trying to print with ABS).In any case, I enlarged the hole on the knob I want to print and tried again Friday, but this time it jammed again. Fortunately it didn't much matter as I made the hole on the knob too large anyway, but it was disappointing to see the jam.I want to buy a roll of grey TPU anyway so the knob color somewhat matches.As for the jamming, no need to reply with more suggestions as most of you already gave some great input. It was my fault for not implementing more such as installing that piece.

author: unseenninja
author_rank: Regular Contributor
timestamp: September 27, 2024, 12:58:32 pm
content: For printing knobs and other small parts with fine detail, a resin printer beats any FDM printer hands down.I had held off getting a resin printer for a long time as they were too expensive. Recently the price of an Anycubic Photon Mono 2 came down to just $150 and that's what I print these types of object with now. The results are excellent.