I have the same problem. I cannot eliminate stringing. It’s fine and wispy and occurs every time there is travel.
Things I have tried:
Normal zhop
Disabled zhop
Disabled retraction on layer change
Disabled wipe on retraction
Retraction 0.2mm → 5mm (0.2mm per step)
Nozzle temperature 190-255 (5c per step)
No part cooling
Max part cooling
Orcaslicer flow test is bang on
Dried Bambu Lab Tough PLA overnight at 50c
Dried and tested Bambu Lab PLA Basic
Replaced hot end with brand new hardened steel one + calibration
Tried printing Orcaslicer retraction tower in latest Bambu Studio
Disabled timelapse
Deleted timelapse G-code
Printing object in different location on the plate
Using external spool holder instead of AMS
Cold pull on both nozzles
Going to have to put a new list of ideas together tomorrow. Wasted multiple days on this so far but at least I am learning a lot. I am guessing there is something fundamentally wrong with my unit. Hopefully not though.
Let me know if you see something I’ve missed.
Edit: Next step will be applying some thermal paste between the hot end and block to see if it’s a heat transfer issue.
Do you have any other brand of pla filament to test with ?
I see they have a travel speed @ 700 mm/s on the A1. Maybe drop it to 250 mm/s to see if it has any effect. It might be pulling filament out of the nozzle with the super fast travel moves.
Unless they have bad batches of nozzles or the part cooling fan is just not cutting it.
I do not have found the proper setting as well…
I do not think it related with the nozzle.
But I do think it has to do with the filament type : brand, type (PLA +, tough, matte, classic) etc.
They all have a different stringing behavior.
Most of the time it is very thin and goes off with the finger or a blazer flame.
However, I noticed one thing after printing the same object several times : stinging appears beside the seam area, just where the retraction happens (the white line and the purple line in the picture). And if you turn the object differently, the stringing follows. I tried and had both cases.
Does it means that the retraction does not work properly and something must be changed ?
Just to show how orientation influences stringing.
Maybe the slicer has something to do with it all. I used Bambustudio. Maybe Orca behaves differently…
Just printed an almost perfect retraction tower in Bambu PLA basic. I put ThermalGrizzly Kryonaut thermal paste between hot end and heating plate then did a bunch of retraction tests starting at 220 and going down to 200. End up going up to 230-235c and it printed perfect.
Will try to do the same with the Tough PLA now.
Also will note that the physical tolerance between the heat plate and the hot end is terrible. I’d like to check with feeler gauges but I need to disassemble it.
So I can’t quite get a stringless retraction tower with the Tough PLA but it’s close. I’ve cleaned the thermal paste on the hotend heating assembly side from between the sensor and the rest of the surface and reassembled doing a few more tests now.
It makes me wonder what you are doing. Fast printers, like the A1, tend to run on the hot side and use dynamic flow control. If you are trying to manipulate it as if it were an old style bed slinger, the results are not going to be desirable. The A1 wasn’t designed to run at 200 C. For PLA it runs at 220 C, the max for PLA. The old style retraction and other towers tend to include g code that can mess with the dynamic flow control system, especially when using an AMS which is quite a distance from the hot end.
What manipulations are you talking about? I am using Bambu Tough PLA with their profile on their printer. I am slicing a retraction test tower in Orcaslicer. The printer strings bad at 220c. Do you think that is normal for the A1? Is the Orcaslicer retraction calibration “old style”? I’m also not going to agree that 220c is max for PLA when Bambu sets their profiles up to 240c on some PLA.
I get these weird strings in normal prints as well which caused me to look into it in the first place.
Edit: Maybe you could be more specific about what you think is not working or what the OP or I have fundamentally wrong.
Edit2: @bernardgaron I am seeing the bad stringing at seams as well. If you watch it during the print you can literally see it create the string on zhop/retraction/travel.
Yes, this may be one of the causes of the stringing problem.
These are my current settings.
So,if stringing occurs with retraction at the seam, maybe we should disable the option of "retract when change layer " ?
But the main question remains why does stringing occurs at all ?
Normally, if you have filaments that behaves differently, then retraction, temperature and speed settings are just there to correct stringing ?
But it does NOT work !
Your tests are here to proove it.
It looks like while retracting, some small quantity of material is not “cut” and is getting pulled between the print and the nozzle.
This stringing problem is all over the web, with different recipes to correct it but no real solution…
Have a look at your stainless hotend to see if it’s twisted. All of mine are not flat. My 0.4 stainless is way worse than my hardened one but I get wispy stringing still with it unfortunately
I just printed an object with a new 0.6 hardened nozzle and 0.3 layer, sliced with Bambu Studio.
It was a catastrophe: stringing was all over !
After looking carefully, I noticed that stringing occurred where the seams were placed, and there was quite a few of them.
I change to Orca slicer and also the seam setting to “Back” and stringing was almost gone.
This proves that stringing occurs at the retraction spot besides the seam and retraction settings have no effect to prevent this, as far as my knowledge goes…
Orientation influences the seam position and quantity, it also depends on the slicer and on the seam setting.
It looks like retraction is not working very well with the A1 mini.
Is it software or is it mecanical ?
Maybe the filament is skiding instead of retracting ?
I can see the wheel turning backward while retracting…
If you go to 240c does the seam stringing go away? Tough PLaa does it worse than Basic for me. There in both though. Better with thermal paste between hotend and heating assembly.
Try placing finger on filament before Bowden tube and see if you feel the retraction maybe.
seams like you guys have ended up throwing the kitchen sink at this. It also Seams, pun intended, you have not found a solution. I am also having this issue as well, only I am using Ninjatek 95A TPU. I have X1 Carbons and use the near generic settings on the bambu slicer without any issues whatsoever. BUT… I purchased an A1 Mini and have copied the settings verbatim. The result is stringing but the biggest issue of all is the Nasty blemishes on the interior surfaces of the print.
Any suggestions here? Have you found a solution?
