Print rough higher up - Possible Causes? Please see pic with zoom

[protechtrader]

Hey all,

I wanted to see if any of you could identify the possible cause of this print getting more rough (it wasnt great to begin with I know) part of the way up? I used a 50x pocket microscope and it seems to be some small gaps (see in pic), but why would something like that start happening all the sudden after 20+ layers? I am new and learning so if you can tell me what types of issues can cause this I will start troubleshooting.

It was a ABS print with 100 bed temp, 220 extruder temp and it is repeatable.

Thanks in advance for your suggestions!

3d print rough changeover regular.jpg

[Sebastian Finke]

Under-extrusion.

Extruder calibration is pretty much a visual process, as opposed to a measured process. Under-extrusion is not that visible at lower layers as they pressed up against the build platform causing them bulge out and produce a bit of back pressure. As you go higher this pressure is relieved and little gaps appear.

[Marm]

Also, the print is smaller higher up, so the time between passes decreases, which can also affect how the layers bind.

A good acetone smoothing will help those layers bond better post print, especially if the print is good enough to keep, but just to harden/smooth the layers out.

But follow SF's solution too, it's probably more right.

[ServiceXp]

I would also add after you confirm your calibration, and if it's still present, try slowing the print down.