Need help understanding reasons for these print artefacts
 
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tonyk
(@tonyk)
Active Member
Need help understanding reasons for these print artefacts

EDIT: pics are not showing up, although they are visible in the edit? why?

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Hello!

short version: printing the same model on my Mk2.5 comes out worse than on my Mk3S, but only on one far side of the print bed, see pictures. Both are on the same extruder revision. Why is this happening

longer version: I've started building keyboards this year, and tried my luck first with small ortholinear devices, for size, cost, complexity and curiosity reasons. I've modelled a housing that comes in two parts. The main upper part is printed upside down. 

Usually, I just drop the file into PrusaSlicer, select, "f" to place on desired face,  "a" for automatic arrangement, which always ends up horizontally on the print bed, with the high side in the back. I use .3 or .35 for quick prototypes. The grey one in the picture was printed in Prusament PETG with .3 layer height. Then its off to the printer, usually with no changes to a preset, especially for the first iterations.

What happens on the Mk2.5S is that the side of the part that ends up facing the far left side of the print bed comes out drastically worse than the right side of the same print, or either side of the same model when printed on my Mk3. It looks rougher and with more irregular lines, as if either the extruder or the positioning of it was having problems. I briefly considered cooling problems, but both Mk3S and Mk2.5S are on the same extruder revision. 

What is the reason for this?

The printer is about three years old, could maybe use more love, but has received upgrades and care. It also prints other models really nicely, as long as they don't straddle that area. 

Any ideas?

screenshot of PrusaSlicer with example configuration for my Mk2.5S screenshot of PrusaSlicer with example configuration for my Mk2.5Sbad side of another print Prusa PETG, .35, bad side of the printbad side of the print Prusament PETG, .3, bad side of the printgood side of the print Prusament PETG, .3, good side of the print

This topic was modified 1 year ago by tonyk
Posted : 26/09/2022 3:12 pm
cwbullet
(@cwbullet)
Member
RE: Need help understanding reasons for these print artefacts

Wet filament or poor extrusion?  I would dry the filament and try to print it an another time.  

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Chuck H
3D Printer Review Blog

Posted : 27/09/2022 2:16 pm
Diem
 Diem
(@diem)
Illustrious Member

One side only?

I would look at belts and pulleys in case there is uneven travel, and I would look at directional cooling, is the print fan off centre for eg.

Check and clean your fans, check your fan ducts, are there drafts in the room?

What happens if you rotate the part by 180 degrees on the print sheet?  Does the poor printing go with the part or stay with the printer?

Cheerio,

Posted : 27/09/2022 3:59 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Need help understanding reasons for these print artefacts

Possible cause:

There should be a gap (~0.5 mm) between the nozzle and the heater block. The nozzle must be tightened in the heater block, locked against the heat break. Failing to do so will cause leaks and an irregular print surface.

wbr,

Karl

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 : 27/09/2022 4:07 pm
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