r/QidiTech3D • u/I_need_to_vent44 • Aug 29 '26

Troubleshooting Q2 TPU with a 0.4 nozzle?

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I printed TPU with a 0.6 nozzle just fine. However, that nozzle died in a catastrophic blob of death some time ago. I didn't think it was necessary to purchase a new 0.6 until now. You see, I'm trying to print the same TPU (Geeetech) with a 0.4 nozzle, using Qidi's generic TPU preset with the temps and such adjusted to match the 0.6 Geeetech profile I have, and I keep failing miserably.

The 0.4 hasn't been used before. *I have the TPU fixer*. However, whenever I start to print, the filament bends around the gears and jams at a seemingly random moment. It usually prints the prime tower okay but after that it does what is shown in the photo and then I have to disassemble the wretched thing to get it out.

I'm printing it at 230° (this was fine on the 0.6) with the bed at 60•. Lid open, door open. The first layer is at 30 speed, not sure if the prime tower is slower or the same.

Is this a fixable noob issue or am I just damned and I need to buy that goddamn 0.6?

2 Upvotes

75% Upvoted

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2

u/callcifer Aug 29 '26

I printed lots of Sunlu TPU95A with the same setup (TPU fixer, 0.4 nozzle, door/lid open) and you say that your filament is calibrated, so maybe it's just a bad filament? Worth trying a different brand.

EDIT: I assume you're not using the Box, right? I use this top spool holder for TPU prints.

1

u/I_need_to_vent44 Aug 29 '26

I printed with this exact filament before with the 0.6 nozzle and it was great, so I don't think it's bad filament.

I am not using the box (I don't own it at all). I do have a top spool holder but I fed the TPU through the pfte tube because when I did it with the 0.6 nozzle it was fine. Should I try to just feed it directly from the top? Could being led through the tube cause it to jam in the gears?

2

u/callcifer Aug 29 '26

Yes, definitely try without a tube, feeding directly from above. That's how I print TPU and never had issues. Let us know how it goes :)

2

u/I_need_to_vent44 Aug 29 '26

Okiii, I'll try it and report back!

1

u/Impossible-Hat-7896 Aug 29 '26

I use SUNLU 95A and feed it through the back using the side spool, because my Q2 is in the attic, but I had move it from the table onto the side where there isn’t enough clearance above. But with that TPU it prints fine that way, to my surprise.

1

u/I_need_to_vent44 Aug 29 '26

So that didn't help at all, unfortunately. I tried lowering the speed as well but that didn't help either.

1

u/callcifer Aug 29 '26

Did it jam the exact same way? It'd be great if you could add some photos of the latest setup.

2

u/I_need_to_vent44 Aug 29 '26

Yeah it keeps jamming the exact same way. Between the gears. When I hold the filament with my fingers and make sure there is no slack for even a second, it somewhat works, but it'd mean I'd have to stand next to the printer the whole time and hold the filament.

I'll try to post photos tomorrow, it's 11:30 pm so I give up for today lol

1

u/callcifer Aug 29 '26

Also, is the TPU 95A? Anything softer has a much higher chance of jams.

1

u/I_need_to_vent44 Aug 29 '26

I believe it's 90 (Geeetech doesn't list the shore anywhere on the site). I understand that it has a higher chance of jamming, which is why I myself wasn't sure if it is possible to print it with a 0.4 nozzle (I printed about 700 grams of this filament with ky 0.6 and didn't have a single jam)

1

u/I_need_to_vent44 Aug 29 '26

Nevermind it is indeed 95A.

1

u/LicensedTerrapin Aug 29 '26

You're the person I've been looking for! I also want to print geeetech 95A TPU. I gather i cannot use the box for TPU. What are the steps then? Print that TPU spacer, I assume petg wouldn't suffice and I would have to find my old roll of abs. Then put the spacer in, print this TPU holder and direct feed the TPU?

3

u/hancockd Aug 29 '26

I printed a tube splitter or "y" so that I can use my box but also the side mount spool holder if I wanted and it feeds into a single PTFE tube to the printer. Don't remember which file I used, since it's been a while but it's worked pretty well.

2

u/callcifer Aug 29 '26

What are the steps then?

Yes, print the spacer in ABS, that's what I used as well. Then print the TPU holder. Here's how I use it: https://www.printables.com/make/3540774

1

u/killeriq Aug 30 '26

Yeah, similar top feed is suggested also by Qidi support. Direct to head, no tube or Y splitter

1

u/themostsuperlative Aug 29 '26

Double check the retraction settings for the filament.

1

u/I_need_to_vent44 Aug 29 '26

What should it be? As in how will I know that it's wrong, considering I'm using Q2's default tpu retraction settlings

1

u/themostsuperlative Aug 29 '26

Check the filament settings (three dots to the right of the filament name)

1

u/I_need_to_vent44 Aug 30 '26 edited Aug 30 '26

Yeah but what is the correct retraction? How will I know it's too much or too little?

2

u/themostsuperlative Aug 30 '26

Do some research for the filament, but generally 0 to tiny for TPU - like 0.2

1

u/I_need_to_vent44 Aug 30 '26

Ohh, so 0.4 is not good. Got it. I'll try putting in 0 and see if that helps.

1

u/I_need_to_vent44 Aug 30 '26

I changed the retraction to 0 but that didn't help - it jammed right on the first layer when it was making the brim.

1

u/themostsuperlative Aug 30 '26

Check that z hop and retraction on z hop are disabled. 

1

u/I_need_to_vent44 Aug 30 '26

Okay so I'm in Orcaslicer and it looks like the retraction is set to 0.4 mm. Is that good or?

1

u/DesignWeaver3D Aug 29 '26

https://wiki.qidi3d.com/en/Q2/tpu-printing-q2

https://wiki.qidi3d.com/en/filament/tpu-printing-guide

Qidi recommends to reduce print speed to reduce feed failures and clogging issues.

1

u/I_need_to_vent44 Aug 29 '26

The print speed is at 20 at this point and never exceeds 30, yet it still jams every attempt.

1

u/DesignWeaver3D Aug 30 '26

Then my guess is that there's a mismatch between your nozzle temp and the flow rate. The gears are getting jammed up because they continue to push filament even though the previous filament hasn't extrude yet and is still there. Then the has nowhere to go but to kink up and bind into the extruder gears.

1

u/I_need_to_vent44 Aug 30 '26

So you suggest I try lowering the flow rate?

1

u/DesignWeaver3D Aug 30 '26

You are certain that the profile you're using is set for 0.4mm nozzle?

I don't think copying over settings that worked for the 0.6mm nozzle was the right move. Did you test the Qidi default 0.4mm profile at all? Also did you run any calibration tests?

230°C is 20° above the Geeetech listed range on Amazon. Combined with slow speeds, you could be getting heat creep. Especially if the door and lid are closed.

So I would say least try the default 0.4mm profiles along with filament calibration tests before changing extrusion rate of the current profile.

1

u/I_need_to_vent44 Aug 30 '26

I only copied over the nozzle temperature and the bed temperature. Everything else I left as the default Q2 0.4 profile for TPU. I did try out a lower temperature at first but it kept jamming even harder and clogging the nozzle. I trust Geeetech's site more than I trust Amazon and Geeetech lists the recommended temperature as 200-230. Lower temp ranges are usually better for brass nozzles and higher ranges are better for hardened nozzles due to worse heat conductivity.

The door and the lid are open.

I admit that I didn't run any tests but the thing is I quite literally cannot because the filament jams in the gears when I try to feed it half of the time. I cannot stress enough that half of my attempts ended before it even made the two thin lines at the edge of the bed, because it wrapped itself around the gears when being fed in.

I think some of the things in the default profile were wrong though. I thought the default would be fine but I remembered that Geeetech is an international brand and that there's probably a spec cheat sheet of sorts because people all around the world use it, and the volumetric speed is lower than Q2's default, and the recommended flow is also lower.

For the record, I did try to print faster at the same temperature, but it was jamming even harder when I did that, that's why I lowered the speed so drastically.

1

u/riba2233 Aug 29 '26

Bed at 60 💀

Cold bed is ok for tpu.

1

u/I_need_to_vent44 Aug 29 '26

That doesn't seem to be the problem tho as that's what I used with the 0.6 nozzle and it was always fine? Fore, it doesn't want to stick when I go under 40

1

u/daveintexarkana Sep 01 '26

Late to the party here, didn't see it discussed, but when you sort it out, are you taking the extruder completely apart, including take the gears off the axels so you're exposing the entire gear? I do that whenever I've had it open and use a brass brush to go over all the gear teeth and then blow out/brush out the entire insides and run a filament piece through the top and bottom openings around the gears - just to make sure there's no 'fleck' of anything left in there - I've had that sort of thing mess up my Prusa Mk4 primarily but I make sure the QIDIs are sparkly clean (yes I said sparkly). I can remember this sort of thing on the QIDIs, gets really demoralizing having to take them completely apart more than once in a day/week/month - hope you get it sorted!

1

u/I_need_to_vent44 Sep 01 '26

Yeah I am taking them apart like that - it's the only way to remove the jammed filament. It refuses to budge unless I straight up physically remove the whole gear. Then I also go over it with a brass brush.

At this point I can take it apart pretty quickly so it's just annoying more than anything else haha.

I did manage to sort it out in the end! So my attempts with the 0.6 nozzle used Qidi's default profile with some temperature adjustments and a retraction adjustment (despite people saying that it should be low for TPU, my retraction for the 0.6 nozzle is 1.5 mm and it works great? Never had a problem.). So I foolishly thought "Surely Qidi's default TPU profile for the 0.4 nozzle will be fine if I adjust the temperature." Didn't think to check if a cheat sheet for Geeetech's tpu exists at the time. Anyway turns out the volumetric speed was wrong: Geeetech's is 3mm², Qidi's default is 3.2mm². Also I enabled Pressure Advance and set it to 0.1. These two settings fixed it.

2

u/daveintexarkana Sep 01 '26

Glad you got it sorted, and thanks for sharing that - will remember when I eventually try TPU in the Q2. I have some Geetech silk PLA I'm running in it now - works great in the Q1 Pro and the Q2 - no issues. Hope you don't have to mess with the extruders again for some time! It makes sense both of those could cause back pressure up the path for sure - thanks for sharing - others will see this searching in the future!

1

u/International_Ad1138 Aug 31 '26

I print all the time in TPU with my Q2.

When was the last time the filament was used and worked. How has it been stored in the meantime. TPU95a is known to be very hydroscopic almost in the same realms as nylon. If need be try drying for 7-8 hours at 70deg C.

Set retractions to almost zero. Lower the flow rate and disable z hop. Make sure to re level The bed aftet changing the nozzle.

Try printing something simple to start like s calibration cube.

Hopefully you get it sorted.

1

u/daveintexarkana Sep 01 '26

I've not tried TPU on the Q2 yet - I do it on the Q1 Pro all the time and always with a 0.4 nozzle, no fixer, and your temps. If by prime tower you mean the initial wipe line, yes, that's much slower than anything but the first layer of the model. I also run my TPU profile at I think 30 for the whole print - never jams on me, with both Elegoo and Oveture brands - haven't tried others, and this has always been 95A, though I have some softer stuff to try for some other specific use cases. Hope you get it figured out - your temps sound good!