strings in a tube

[Clemipix]

Hi all ,

I've another problem with an extrusion : it's a tube ( 2cm outside diameter ) and it has to receive a 'male' part so it's shaped as a female part . The problem is that I get strange strings just after the diameter shrinking area . Maybe it has tried to close the tube doing a kind of membrane or such ?

Any idea from where it comes from ? I've tried modifying the Bridge options too but no success .

[greybeard]

Basically two types of stringing problems:
#1-when nozzle pulls away and leaves strings; can happen anywhere on part
#2-poor adhesion of filament to nearby filament or to bed

Your problems looks to be #2 and is most likely due to not sticking to the Bed.

Ensure it sticks to bed:
-use something such as glue-stick, tape, homemade sauce...
-reduce the gap between nozzle tip and bed (I use thin paper for a shim).

[Clemipix]

Hi Greybeard ,
well the big ring part is on the Bed in fact , so it extrudes correctly till it arrives in the smaller diameter area , and there it creates the strings , just at the begining , and after it finish extruding the smaller area without any problem . something occures when it starts extruding the smaller area but it's inside the main tube so it's not possible to put it on the bed ( and I'd prefer not to add supports inside too as it's for a musical instrument and want to preserve a nice smooth surface inside )

[greybeard]

Ahh, I see. Without having posted your parts file, it's difficult to really know what the problems could be.

However, realizing from what you described and seeing more the photo more clearly, I see you're talking about the 'Overhang'. It's difficult to print in 'Air' without supports unless Bridging between two features.

But, if you can Chamfer the undercut of the overhang, it should print ok. Be sure your settings are to print from Outside-In, not Inside-Out.