Issue with 0.25 nozzle PETG and external perimeter stringing/lip
 
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Charon
(@charon)
New Member
Issue with 0.25 nozzle PETG and external perimeter stringing/lip

Trying to print a PETG case with a 0.25 nozzle and 0.1 layer height. But its causing stringing and odd build up on the outside of the print. The inside looks great, fill is good and its not lifting from the bed. But when printing it feels like its creating a raised lip along the outside perimeter and may be dragging the nozzle through or causing the stringing as in the photo? 

Could it be over extrusion? 

I have some of the following settings for PETG

Extrusion Multiplier: 1.03, Speed is really slow max at 40mm/s, Extrusion width is 0.3  with first layer and external at 0.35, Temp 230

Higher res photo: https://imgur.com/a/MxHH9cf

This topic was modified 5 years ago by Charon
Posted : 21/05/2019 6:35 pm
bobstro
(@bobstro)
Illustrious Member
RE: Issue with 0.25 nozzle PETG and external perimeter stringing/lip

PETG is stringy by nature, so there's only so much you can do. You can disable z-hop if not needed, and play with retraction and wipe settings. A small nozzle can require very different settings than a larger one. A quick pass with a heat gun may be your best bet.

How did you arrive at that extrusion multiplier? Over-extrusion will definitely contribute to stringing.

A 0.25mm is really likely to be a waste for something that's supposed to be durable like a case unless you've got a lot of detail on the horizontal surfaces. Thicker extrusions from a larger nozzle will be much more robust, not to mention much faster to print. A 0.10mm layer height is similarly not likely to gain you a lot for a case unless it has a lot of detail in the vertical surfaces.

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 21/05/2019 10:13 pm
Charon
(@charon)
New Member
Topic starter answered:
RE: Issue with 0.25 nozzle PETG and external perimeter stringing/lip

I am printing at .25 as I am looking for detail. And the strings are not so bad if it was just the strings. But they are kinda globing on the outside and creating larger messes. I was able to print at this .25 before with a nearly perfect finish but cannot seem to do that again. 

I have another print running, but its globbing a little bit on the outer perimeter, not sure as to why. The inside perimeters look really good. 

Posted : 21/05/2019 10:16 pm
GregB
(@gregb)
Trusted Member
RE: Issue with 0.25 nozzle PETG and external perimeter stringing/lip
Posted by: Charon

I am printing at .25 as I am looking for detail. And the strings are not so bad if it was just the strings. But they are kinda globing on the outside and creating larger messes. I was able to print at this .25 before with a nearly perfect finish but cannot seem to do that again. 

I have another print running, but its globbing a little bit on the outer perimeter, not sure as to why. The inside perimeters look really good. 

Might it have something to do with the atmospheric conditions?  I'm thinking of that as we enter another humid summer.

Posted : 22/05/2019 8:26 pm
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