P1S print stringing issues on parts with lots of retractions

I have tried drying the filament, increasing retraction distance .5mm and 1mm (if anything issue got worse), Slowing retraction speed multiple different settings. Nothing has fixed this issue. I did not have this issue for a long time, and it has started more recently on this part specifically that has a lot of retractions. Don’t have this issue on other parts.

I am printing on a P1S with Bambu PLA basic filament. .4mm nozzle base settings. Variable layer height.

Nothing I try seems to improve it at all. Other parts I print that don’t have as many retractions don’t have the issue at all. It is just mainly this one part. I can clean it up with a butane torch, but that is annoying and the finished part does not look as smooth.

Did you dry according to the Filament Drying Recommendations | Bambu Lab Wiki?

Yes, I did. I tried the recommended by Bambu and tried other sites recommendations for drying PLA and no luck.

Strange. Usually that does the trick for PLA in combination with a good calibration.

Did you print abrasive filaments recently? Nozzle wear is another factor that could result in increased stringing.

What I have found to help a lot with PETG is to enable “wipe while retract”.

:crossed_fingers:

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If you use a Bambu filament you might not change the defined printing parameters, but I noticed Bambu uses mainly a top range temperature. Decreasing it 5° to 10° might solve the issue.

Whenever I’ve experienced fine stringing like with Bambu filament it is because my filament had moisture in it.

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Forgot to say in the initial post I tried replacing the nozzle also.

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I actually tried this as one of my first things to try and then at the same time ran into some bad filament that was printing horribly. Thought it was bc i lowered temp, but found out 6 rolls later that it was just a bad batch of filament… I will try this again and see if it helps.

I have tried drying multiple times and at different temps and lengths and none seem to help

Can I ask how you are drying it?

Perhaps I missed it. Is this happening with multiple different spools or only one?

IMG_9989

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I run a lot of these parts I have probably gone through 15-20 spools all doing this. I dry using a Creality space pi dryer 2 spools at a time.

It isn’t wet filament. I have dried it so much it became rubbery and still did this lol :joy:

You’ve appeared to have done most of the common troubleshooting tests. Three things I did not see mentioned though that may be something to review.

  1. If you’re using an AMS, have you tried running it directly to eliminate the AMS from interefering with the retraction?
  2. Have you inspected the extruder gears when you replaced the nozzle for wear and tear and when you replaced your nozzle did you go back after this stringing occured to make sure the extruder did not somehow come out of alignment. Extruder slippage can influence stringing.
  3. Did you inspect the PTFE tubes for wear? That’ really unlikely but try it to rule it out.

One test you can run is a stringing test with the filament hand-fed directly into the nozzle without the PTFE only to see if it affects the results.

A simple 3 prong string test will be enough. Here’s a cut model I use from the String Hell Test from Orca slicer. It takes only 10 minutes to run.
Orca Stringhell.3mf (56.5 KB)

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I stand by it.

Thanks for the reply.

3.I did recently replace all my PTFE tubing and it has not made a difference on this issue (made a difference of my filament wearing through the tubing and not feeding to my printer :rofl:).

  1. I have not checked the extruder gears. I will look at that tonight.

  2. I am using AMS. Although this part is only black, so I could try this. Have never even installed the back bracket for the roll of filament :grin:

While I’ll admit this is a longshot, you are running out of diagnostics steps so that is one that hasn’t been tried.

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The one question I did not see addressed here which really should have been the first question. Does this do this with any other filament?

I ask because Bambu filament lately has gone through some changes and there have been lots of quality complaints. It could be as simple an issue as a bad spool. Trying another manufacturers filament will at least rule out a bad batch if the same issues occur. Of course you will want to calibrate that spool from another maker and simply not rely on defaults.

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I got a couple suggestions to try here I will try out.

  1. Adjusting temp of the nozzle down a bit I need to test again.
  2. Checking the gears for wear on the extruder.
  3. Not using AMS to feed the filament.
  4. Using non bambu filament.

I’ve had success by reducing the extruding temp down a few degrees. Try the lower-end of the extruding temp. I also have a very sharp exacto knife and one of the little irons used to smooth out PLA. I use those a lot when it comes to intricate prints that tend to spiderweb a bit.

this is also a good fix for stringing issues, temperature is an easy adjustment