Started getting incomplete coverage/holes in flat horizontal surfaces
 

Started getting incomplete coverage/holes in flat horizontal surfaces  

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Marc Liyanage
(@marc-liyanage)
Active Member

My Prusa mini was working perfectly for months using different materials until today, when I started getting these stretches of incomplete coverage in solid horizontal areas shown in the photos below. The failing print was something small that I printed several times successfully over the last few days with the same roll of filament (Prusament PLA).

After I noticed the failure mid-print, I cancelled the print and did a purge and then I tried again and I am getting the same issue.

The only thing that could be related is that today I tried to clean the hotend, which had some PETG smeared all around it from earlier failed prints a while ago. That crusted material alone did not cause any issues, it was just cosmetic.

I tried to clean it first by just heating it up and pulling away the material, but it is just a very thin layer so that didn't do much. I then tried to let it cool down and clean the hotend with a bit of acetone on a paper towel. That also didn't do much so I just left it alone, since it didn't impact the printing.

Then later today I started getting these issues.

I checked the Prusa knowledge base but I did not find any photos that looked like my issue.

 

 

 

 

Posted : 20/11/2020 5:49 am
karl-herbert
(@karl-herbert)
Illustrious Member
Posted by: @marc-liyanage

My Prusa mini was working perfectly for months using different materials until today, when I started getting these stretches of incomplete coverage in solid horizontal areas shown in the photos below. The failing print was something small that I printed several times successfully over the last few days with the same roll of filament (Prusament PLA).

After I noticed the failure mid-print, I cancelled the print and did a purge and then I tried again and I am getting the same issue.

The only thing that could be related is that today I tried to clean the hotend, which had some PETG smeared all around it from earlier failed prints a while ago. That crusted material alone did not cause any issues, it was just cosmetic.

I tried to clean it first by just heating it up and pulling away the material, but it is just a very thin layer so that didn't do much. I then tried to let it cool down and clean the hotend with a bit of acetone on a paper towel. That also didn't do much so I just left it alone, since it didn't impact the printing.

Then later today I started getting these issues.

I checked the Prusa knowledge base but I did not find any photos that looked like my issue.

IMG_0571.jpg

Under extrusion, partially clogged hotend, too high friction in PTFE, nozzles temperature fluctuations or irregular extruder filament transport. A widespread and frequently discussed problem:

https://help.prusa3d.com/en/article/clogged-nozzle-hotend-mini_112011

https://help.prusa3d.com/en/article/extrusion-problems-prevention_2027

https://help.prusa3d.com/en/article/under-extrusion_2007

https://help.prusa3d.com/en/article/under-extrusion_2007

https://help.prusa3d.com/en/guide/how-to-replace-a-hotend-ptfe-tube-mini_119449

 

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 20/11/2020 12:49 pm
Marc Liyanage
(@marc-liyanage)
Active Member

@karl-herbert

Thank you! The https://help.prusa3d.com/en/article/under-extrusion_2007 article has photos that look exactly like my issue, I'll try the various fixes.

One thing that I forgot to mention is that the very first layer always looks good, the problem only appears on higher layers. I was a bit surprised about that. 

For reference, this is the article I checked, a list of print quality issues: https://help.prusa3d.com/en/tag/mini/print-quality-troubleshooting_225. It doesn't seem to have an entry for under-extrusion, but it probably should, given that it seems to be a common problem.

 

This post was modified 5 months ago by Marc Liyanage
Posted : 20/11/2020 6:14 pm
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