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Sticky residue buildup in PTFE Tube (lemm.ee)
submitted 1 year ago* (last edited 1 year ago) by zevrant@lemm.ee to c/3dprinting@lemmy.world
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Trying to reduce the amount of constant maintenance the my ender 3 printers require and one of the biggest issues i'm having is a buildup of sticky residue inside the ptfe tube inside the hotend/ptfe tube. It's not leaking as i visually inspect before cleaning and i can see where the tube connects and there's a clear line and no visible signs of leakage. Usually some rubbing alcohol and a scrub brush will fix the issue for about 100hours of print time before needing to clean it again.

I'm wondering if i might need to reduce the flow rate on the printers or maybe i'm missing something. Running this with a direct drive extruder so the ptfe tube is pretty short and since the residue is building up inside the heater and nozzle too i don't think that's the issue.

Things i have tried:

  • less heat printing at 200 instead of 205 - marginal / no difference
  • printing speed turned down to 20mm/s - it takes longer for the buildup to become an issue but it also takes as long for the prints to complete
  • lowered retraction distance i thought the high retraction distance might be causing issues, while it made it better now i have stringing to deal with

EDIT: Added requested Photos -> https://imgur.com/a/XPKGI7D

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[-] rambos@lemmy.world 3 points 1 year ago

BTW if you didn't mod your printer you don't have direct drive. Bowden tube is not long, but its still bowden setup. I'm not sure what sticky thing is, but it can be filament, PTFE or dust (on the outside of your filament - you can guide filament trough some kind of sponge to clean it before extruder). Nothing else should be there. If reducing retractions fixed the problem you might check your hotend fan. For high retractions you need proper cooling to avoid heat creep (assuming thats the problem). Not having all metal hotend with heat break makes it much harder ofc. What retraction settings do you use (now and before)?

You can also reduce stringing by increasing travel speed, using lower temps and smaller nozzle.

[-] rambos@lemmy.world 3 points 1 year ago

Just make sure you didn't melt PTFE since its kinda unhealthy

[-] Rolive@discuss.tchncs.de 1 points 1 year ago

It's unhealthy for us and will quickly kill (pet) birds. Better get an all metal hot end. I've had good success with the MicroSwiss on my Ender 5.

[-] rambos@lemmy.world 1 points 1 year ago

Yeah all metal is proper way of doing it , even tho lot of people had great success with stock hot end. Im confused because it looks like OP have all metal

[-] Uranium_Green@sh.itjust.works 1 points 1 year ago

Am I being silly?

To me it looks like the stock ender 3 V1 hot end that OP is using, which I didn't think was all metal, then again I don't know what constitutes all metal...

[-] rambos@lemmy.world 2 points 1 year ago

In all metal hotend ptfe should not go all the way to the nozzle. Nozzle should be tightened against the heat break to stop heat from going upwards. Ptfe just guides the filament, upper area is not heated and therefore cant leak unlike ender style hot end that requires pressure between ptfe tube and heated nozzle.

[-] Uranium_Green@sh.itjust.works 1 points 1 year ago

I want to say PTFE starts to become a problem around 240C, so it shouldn't be that, but this advice is useful.

I'm curious as to what filament OP is using and if they've got a picture of the residue...

[-] zevrant@lemm.ee 1 points 1 year ago

will get a picture out soon but it's the wholesale stuff creality sells or at least used to sell on the cheap

[-] zevrant@lemm.ee 1 points 1 year ago

pictures can be found here https://imgur.com/a/XPKGI7D

Apologies for the blurriness the stupid camera wouldn't stop auto focusing on the wrong parts of the frame

[-] zevrant@lemm.ee 1 points 1 year ago* (last edited 1 year ago)

it's probably not fair to call it an ender3 how modded it is at this point :) also it didn't fix the problem just made it noticeably better.

Retraction was at 7mm but was causing clogs due to heat creap so i reduced it to 3mm.

I'm not worries about stringing as much as the residue

[-] rambos@lemmy.world 1 points 1 year ago* (last edited 1 year ago)

Pic would help, but it seems like be your bowden tube is not seated properly. I had 5-6 mm retraction on 750 mm long bowden tube, and after I reduced play in push-fit connectors Im using <5 mm. If you need 7 mm to remove stringing its obvious sign that something is wrong. Make sure your bowden tube is not moving too much. You can try diferent retraction speed as well. Also, some filaments are just bad with stringing, especially wet petg. Sometimes I have to accept some amount of stringing to avoid using dangerous retraction distance.

To fix play in bowden tube, you can cut 10 mm of tube on both ends. Your locking mechanism will bite fresh part of bowden tube. After you push the tube in the connector, lift collar with your nail, then push the tube even more, then press the collar in and pull it out with safety clip while still pushing bowden tube.

It might be diferent on your hotend side, since your nozzle will push against bowden tube. If you have play there you will have bad time (leaking, clog, etc).

Make sure you cut the tube perpendicular enough for good joint and tighten your nozzle when heated

Edit: typo

[-] zevrant@lemm.ee 1 points 1 year ago* (last edited 1 year ago)

the 7mm was a holdover from before i moved the extruder over to be mounted onto the x axisi don't care so much about strining that's simple to fix it's the heatbreak clogging that's the issue. As mentioned above, it's not an issue with improper bowden seating as the residue is only inside the heatbreak and not where the ptfe tube sits. Also the ptfe tube is factory cut so definitely not the issue there. Nozzle does not push against the hotend tube as it sits on top of the heatbreak and does not go all the way through.

I'm thinking probably heat creep but turning down the temps should have helped with that.

there are pics please look at the imagur link.

I cannot post the pictures directly as the site is broken and i get a 400 invalid json error.

in case you didn't notice the edit: https://imgur.com/a/XPKGI7D

[-] rambos@lemmy.world 1 points 1 year ago

Is this your hotend?

You moded your hotend by any chance?

[-] solarbird@kbin.social 1 points 1 year ago

Y'know just in general I really strongly recommend going all-metal or better bimetallic on your hot end? It cleared up so many problems for me. The Ender 3-series hotends really aren't bad if you just back that PTFE up a bit.

I like this one (no affiliation other than I bought one) quite a lot, and I got it on sale so it was cheaper than the current price. But even at the current price I'd definitely say it's still worth it.

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this post was submitted on 27 Jul 2023
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