Printer: P1S
Nozzle: 0,4
Filament: SUNLU Meta PLA
Print-Temp: 220°C
Hi,
I am having trouble getting rid of loose strands of filament (strands which i can pull of the print because they dont stick to the rest of the print) when printing stuff with overhangs and activated tree supports. I hope someone can give me a hint what the problem is… Is it the temperature, or rather the support settings? I have set top z distance and support/object first layer gap to 0,25 as I have seen it in a video regarding best support settings…
Hi @Vortilion ,
It would help if you would be able to show pictures of the defect. It makes troubleshooting much easier.
In general, the first thing to do when observing stringing is to dry the filament. Especially new filament has travelled the seven seas in bags that are not able to keep moisture out completely. And moisture in the filament needs to be driven out by heat.
There are other defects though which may occur and some visual information would be helpful. Are the strings more akin to hair like whisps or thicker strands like thin twigs? The former points to drying, retract settings while the latter indicates, for example, nozzle wipe issues.
& 
Based on your description, it sounds like the outer wall is getting dragged instead of staying put. If so, there are a few ways to tackle this.
-
Layer Height will affect how much material the outer wall will have to hold on to. Contact comes from the inner wall and the layer below it. In the below example, the one on the left has very little to stick to. The one on the right has smaller layer heights which overlap and provide more contact for the outer wall.
Since setting a small layer height for the entire model can lead to increased print times, you can use something called adaptive layer height aka variable layer height.
Variable Layer Height | Bambu Lab Wiki
-
Outer wall speed - lowering this value will give the outer wall a longer time to cool and adhere to the inner wall and the layer below it. To reduce it, there are a few ways. The easiest is to simply reduce the outer wall speed for the entire model. A more targeted approach would be to use a modifier to target just the overhanging layers for a slower outer wall speed. Another way to target overhangs only (without modifiers or slowing down the whole model) would be to lower the % values of overhang speeds (on the Speed tab in Process settings in Studio). Note that depending on the filament this can affect the sheen of the outside of the part. Generally I favour reducing the overall outer wall speed so as to get a consistent finish. But if speed is favoured over sheen, then the target approach is better.
As for which to use, sometimes you need both, sometimes one or the other. Both will affect print times. I would play around in the slicer to see how it impacts print time and whether it matters for your particular needs.
4 Likes
