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PETG Blobs on nozel  

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MasonVX
(@masonvx)
New Member
PETG Blobs on nozel

Hallo, 

I already did quite a bit of research, but I seam not to find a proper solution.

I'm printing with Prusa white PETG and I'm using the settings in the Prusa slicer. I usually have issues with blobs forming under the nozzle which is a problem especially when I'm doing large area prints. I usually make a 2-3 breaks inbetween the prints to remove the blob, but I can't seem to fix it. I reduced the flow to 97% which seems to help a bit but I believe it makes the top layer look bad (see picture).

I should mention that I have the printer in an enclosure. I'm happy to provide any further information.

Any help would be greatly appreciated. 

This is the nozzle after I removed a blob after print

Here the top layer of a print (you might know the print from the prusa blog), which I'm also not happy with.

I made a photo during print and marked the blob.

 

Posted : 18/05/2020 11:20 pm
MasonVX
(@masonvx)
New Member
Topic starter answered:
RE: PETG Blobs on nozel

Ok, I found the solution myself and I'm gonna explain the problem, if someone else has the problem.

It seams, that even so I thought my first layer was fine, it was actually to low, which kind of dragged the nozzle all the time through the filament.

I was about 110 um to low. 

I took time and kind of used the method:  Live level adjustment

I think the most important thing is to just print one square an make rather obvious changes. In the picture I tried 6 different heights and when you put you finger over those, it is pretty obvious what is good and what is bad. Those vales are minus values.

 After the first one I did an other one with less changes.

 

I ended up with 618 and I did a 10 hour print yesterday and I had no blob problem during the print, where I had to remove blobs before every 30-40 minutes with the help of a print pause.

 

Another thing I did, I adjusted the starting g-code in prusa slicer so that it heated the bad with first layer bad heat and the nozzle up to 160 degrees. Than I did the leveling, moved the head to wipe position and heated then the nozzle up to the first layer extrusion temperature. This way you have no problem with dripping filament which you need to remove before the print.

For the gcode adjustment I orientated my self on this article: Bob’s Project Notebook gcode custom

Maybe this helps someone who has the same problems.

 

Posted : 20/05/2020 10:32 am
Don and bobstro liked
Don
 Don
(@don)
Active Member
RE: PETG Blobs on nozel

@masonvx

Thanks for this. I am printing with PETG as I type, and just paused to cut a small blob off of my print. 

 

 

 

Posted : 05/07/2020 3:40 pm
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