So I just started having this issue. When I print and the model has a hole (for magnets) and its printing, when the top of hole is printed, directly after that is lines and layer adhesion issues.
I’ve run a bunch of calibration tests and tuned what I could but don’t understand what is happening here.
which material?
If it is PETG basic, that filament was seriously flawed. Reducing all speeds to 100 or max 120 should help.
It’s probably speed related. Recent update did some major changes around overhang speed changes and the smoothing of them.
Use the preview ‘speed’ view. Does it expose the issue? That is you would see color changes right where the issue is. If so smooth it out by setting smooth coefficient on quality tab to 0.1, and or get outer wall and overhang speeds closer together.
Whats the pressure advance set to? Also, what is minimum fan speed set to? Could try a lower PA or try setting minimum fan to 0 and unchecking “keep fan on always”.
Ive seen both cause it. Pa being high or fans being high when the printer is moving slow. Overcooling the areas that the printer is slowing down for. Causes that layer to shrink
I have all my speeds at 100 or less already. Thanks.
Pressure advance is set at 0.042. That was calibrated 4 or 5 times to get to that value.
All thanks for the advice. Looking at each of these and seeing what I can come up with.
try .02, Just to see. .042 is pretty high. Not saying you do this, but when doing the pa line test, dont just look at the right side of the lines. The left side will show you acceleration and the right shows deceleration. You want to pick the middle ground of both. Looking only at the right side will give you a higher pa #
I don’t normally use the PA Line test. I use the tower method. I’ll try the line method and see what I come up with. Thanks.
So my guess of material was right? You haven’t answered that yet 
The Bambu PETG basic is the only filament that I have made similar experiences with.
Maybe in addition to reduced speeds, you also have to reduce accelerations?
Sorry, yes it is Basic PETG. I’ve slowed down my speed below every recommended speed by significant amount. I am currently doing a print with my accelerations also reduced.
With PETG Basic, I usually use speeds below 100 and accelerations at 25% of defaults. For curling prevention in overhang areas (such as holes) I also use adaptive layer height.
I just run it at its max flow rate minus 5.
Thanks for all the help. Speed helped, PA helped, acceleration helped, and the variable layers fixed what the others did not.
