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Prusa i3 MK3S printing little blobs in line prints  

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SnoothDogg
(@snoothdogg)
Active Member
Prusa i3 MK3S printing little blobs in line prints

I've looked through the topics and haven't come across this yet.

Has anyone seen this issue where it prints blobs in line prints?

the attache photo is the z collaboration test print, if you look at the line, its not a solid line, its blobby. I've pushed it up and down tried everything height of the z axis to see if it makes a difference and it doesn't.

I've  had it for 4 or 5 months and it has been an amazing printer and was printing perfectly, until now (nothing changed either) but it doesn't seem to be sticking that well to the bed, it doesn't appear nicely squished (first layer) anymore.

Any thoughts on what it could be?

Best Answer by Peter M:

Check your first layer, i think you need to go lower.

Filament with water inside, raise the z-axis, then extrude filament for longer time, see if it bubbles, then you have to much water in it.

And check, spring on the extruder, and if extruder wheels/teeth are correct build.

Posted : 20/04/2020 8:37 am
SnoothDogg
(@snoothdogg)
Active Member
Topic starter answered:
RE: Prusa i3 MK3S printing little blobs in line prints

Seems to just be the first layer only, strangely still sticks to the bed, just doesn't look good when finished.

I watched it in slow motion and it kind of looks like its either not pushing enough filament out during the first layer or its just not sticking to the bed at certain points and is being dragged to cause the blobby look.

Any help appreciated.

Thanks.

Posted : 20/04/2020 8:52 am
SnoothDogg
(@snoothdogg)
Active Member
Topic starter answered:
RE: Prusa i3 MK3S printing little blobs in line prints

Ok I think i found the problem.

I had recently upgraded firmware on the MK3S and for some reason, I had to choose the smooth1 board again, now it squishes better and doesn't blob anymore.

Just in case someone else has this problem

Posted : 20/04/2020 10:16 am
SnoothDogg
(@snoothdogg)
Active Member
Topic starter answered:
RE: Prusa i3 MK3S printing little blobs in line prints

Ok no.. I called it too early, that didn't fix the problem either, the second print is still the same, could it be the bed isn't heating evenly?

Posted : 20/04/2020 10:25 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Prusa i3 MK3S printing little blobs in line prints

try washing the buildplate with soap and water, rinsing with hot water and drying with paper towels
handle the build plate by it's edges
Make sure your printer is set to use 7x7 mesh bed levelling (49 test points, instead of the normal 9 test points) set this through the LCD Menu!

then try the live Z adjustment process, here

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/

there are three files in a zip file, at the bottom of the first post...
regards Joan 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 20/04/2020 4:04 pm
Peter M
(@peter-m)
Noble Member
RE: Prusa i3 MK3S printing little blobs in line prints

Check your first layer, i think you need to go lower.

Filament with water inside, raise the z-axis, then extrude filament for longer time, see if it bubbles, then you have to much water in it.

And check, spring on the extruder, and if extruder wheels/teeth are correct build.

Posted : 20/04/2020 4:07 pm
Area51
(@area51)
Member
RE: Prusa i3 MK3S printing little blobs in line prints

To me it looks like there is too much moisture in the filament causing bobbles to form when it is heated, as peter-m26 also mention. To test, extrude filament in the air and observe it bobbles is formed and listen after a cracking/popping noise.

Another indicator for too much moisture is that the filament keeps oozing  when preheating.

Solution is to dry the filament in an oven or food dryer.

Have a look at my models on Printables.com 😉

Posted : 20/04/2020 10:08 pm
SnoothDogg
(@snoothdogg)
Active Member
Topic starter answered:
RE: Prusa i3 MK3S printing little blobs in line prints

OMG.... Thank you @joantabb, @peter-m26 and @area51.

Yes you guys are right.. it was the first layer, took your advice and reduced to -1.190 from -1.175 and it made all the difference.

I've printed 5 times now and all has worked perfectly again.

I dont know how it became an issue after upgrading firmware to 3.8.1.

But anyway, thank you so much everyone.

 

Posted : 21/04/2020 9:08 am
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