ugly print needs help diagnosing [solved]

[ultradryan 9]

 

my ultimaker 3 was working just fine most of the time, until i hv to print this egg (with PLA).

the bottom left of the egg always got deformed, always the same spot, the bottom left part where it faces the left side of the printer, no matter how i rotate it.

I suspected bad bed leveling causes the issue, so I hv tried to do manual and active bed leveling, problem persists, still the same spot gets deformed.

 

It seemed like the egg was cooling down unevenly while print, causing the left side to somewhat accumulate oozing and collapse.

Interestingly, I hv no problem printing other things, and if this egg was printed up side down, similar problem does not occur.

 

Any one hv any idea why this is happening?  really wanna print it just up right without that deforming.

 

[UPDATE]

 

PRINTING slower or setting minimum layer time does solve the problem. it seemed that the accumulated oozing and collapse was caused by not enough cooling time per layer.

 

Although it is unclear why the part where it collapses always happens on the same spot.....

 

Edited May 14, 2019 by ultradryan

[geert_2 556]

This reminds me somewhat of my cooling-tests (colorFabb PLA/PHA):

 

 

When printing rather hot and on small areas, the surface does not get enough time to cool down, and the nozzle above it keeps radiating heat. So the model stays molten and it gets this weird overextrusion effect. Adding a dummy cooling tower (right models) reduces the effect, but does not eliminate it. The blobs tend to accumulate more on one side.

Another effect that I see on overhangs, is that the overhang curls up, and then the nozzle bangs into it and pushes it down again. This also gives an ugly sidewall with lots of defects and ridges.

 

I am not sure if these are the effect you experience, but it could be? Printing as cool as possible, slow, and with larger layer heights for overhangs, seems to help for me. Layers of 0.2mm give a much better look than my usual 0.1mm. Also use more than one sidewall, for added stability.

 

[yellowshark 153]

@geert_2 is right, on that geometry slow and cool is key. I wonder what your settings are?; personally I would go no faster than 30mm/s and 190-195 degrees depending on layer height. Now another thing that could help you...

 

These two versions were printed with the same filament and settings except the first one used a 0.4 nozzle and the second one a 0.8 nozzle. I guess I may have pushed the extruder temp up 5 degrees for the extra flow of filament from the 8mm nozzle. I cannot guarantee it would work, your curve is convex and mine concave but the principle is the same, more material in the the wall being printed laying down on the previous layer. Err lol I was shocked too!

Edited May 14, 2019 by yellowshark

[ultradryan 9]

3 hours ago, yellowshark said:

@geert_2 is right, on that geometry slow and cool is key. I wonder what your settings are?; personally I would go no faster than 30mm/s and 190-195 degrees depending on layer height. Now another thing that could help you...

 

These two versions were printed with the same filament and settings except the first one used a 0.4 nozzle and the second one a 0.8 nozzle. I guess I may have pushed the extruder temp up 5 degrees for the extra flow of filament from the 8mm nozzle. I cannot guarantee it would work, your curve is convex and mine concave but the principle is the same, more material in the the wall being printed laying down on the previous layer. Err lol I was shocked too!

Thanks all, printing slow does fix the problem. At first i thought it's the leveling that caused the collapsing. Printing slow or with a prime tower does allow more time for cooling and solved the issue.