Sticky residue buildup in PTFE Tube
Sticky residue buildup in PTFE Tube
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
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.
Just make sure you didn't melt PTFE since its kinda unhealthy
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
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
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.