Printing transparent PLA: stringing within object with 0% infill

[manuelherz 1]

Hello

I'm trying to print a model, that has a basic spheric geometry, but it has a "puffy" or "pillow-ish" double layered skin. I need to print it in a translucent material, and I'm using transparent PLA from the company "Herz" that usually prints very well. (Ultimaker PLA transparent is too yellowish)

I'm printing with a 0.4 mm nozzle, 0,15mm layer height, and have set wall thickness to 1.2mm (i.e. 3 lines) I've also set the infill to 0%, as otherwise I would see the geometry of the infill. (I don't want 100% infill, as this makes the model grey and dull)

During the printing process, unfortunately stringing develops within the thickness of the "puffy" walls. It's not typical stringing of thin lines, but rather has a pearly shape. As I'm printing with transparent material, this starts to shimmer through, and makes the model look messy.

Any advice how to solve this??? Is there anything I can do with print speed, or material flow, or anything else??? I'm getting quite frustrated...

thank you for your suggestions!!!

 

(for some print settings see screenshots)

[gr5 2,266]

The secret word is "combing".

 

You want to disable combing.  And you want to make sure it's really really off so there are probably 2 or 3 other combing settings.  Combing is the word that describes movements within the walls - movements in areas where you normally have infill or shells.  Note that even when you disable combing I think it still combs if the distance is below a certain distance?  Or maybe not.  So here's how you test it before you print:

 

Go into PREVIEW mode after you slice and scroll throught the layers.  Make sure you are looking at it with color scheme set to "line type" and make sure the travel moves (blue) are enabled so you can see them.

 

Now light blue travel moves are retraction moves (this is what you want).  Dark/saturated blue travel moves are non retraction moves (bad - creates internal stringing).

 

Make sure you tweak the settings until all (or 99%) of the dark blue lines are gone.

[manuelherz 1]

Thank you gr5 for your prompt response. That's very helpful.

I have found only a single (main) setting for combing, and have turned it off. Now the preview mode only shows me light blue lines. You're right, that there were many dark blue lines coinciding where these artefacts are appearing in the actual 3d print.

I will try printing the new file as soon as my printer is finished with the current model. 

Thanks so much for your help!