PLA-CF usually prints very nicely, with a few exceptions. Recently I run into an issue, where surface quality was very poor. It’s an overhang, but normally should not be a problem.
I reprinted only the relevant area of the initial part. Turns out, that the overhang is in perfect quality. Since I have not changed any settings which would be related, I don’t really know where to start. I have even tested various orientations of the part.
Left: poor surface quality. Right: exact same area reprinted with perfect quality. I printed one by one, so no changes regarding overall layer time of the print.
If you see the issue, any suggestions what happened and how to avoid it?
Yes, I also realized that. That is why I was expecting the same to happen to the small part, but it did not. I just printed with standard settings, PLA-CF profile with 0.16mm layer height.
I wonder whether you had some different settings… Perhaps wall order (inner/outer/infill, etc) was different, or max flow was different, or speed was different…
Otherwise the only other thing that comes to mind is vibration/sway, but your model isn’t that tall & skinny.
I’m still working on this issue. I have tried almost everything, as well with bambulab support. I have not found a solution yet.
I have two prints, one is ok, the other one fails. The only obvious difference is that for one print I use 3 colors, in the other one only 1. The print with 3 colors does not work. But since the area of bad surface quality is in completely different layers you should assume that the amount of colors has no impact, right?
I have tried to print only the overhang section many times. I have changed print speeds and have found out that quality is ok for outer wall speeds <50 mm/s. I have varied amount of walls and infill but could not reproduce the error. I even tried differnt orientations to proof that air flow does have no impact.
Ok, what I found out so far is that changing the wall sequence (first outer wall, then inner wall) significantly improves the surface quality.
But there is still something weird. I have created a test part, which I printed in two versions, one with a support layer, one without. All other settings are the same. I printed twice, and I interchanged the positions, to account for the side fan.
As soon as support is involved, something seems to change.
I thought that maybe heat flows change because the support layer somehow insulates more towards the heated bed. But if that would be the reason, the change of surface quality should change in the layers after and not towards the end of the print.
I have sent both files to Bambulab and I hope, they can find a bug or find out at least, whats different.
Take the standard profile for 0.16mm.
-Change outer wall speed from 200 to 50mm
-turn off slow down for overhang
-change wall order (first outer then inner wall)
These adjustments were not good. The first layers come impurely.Are there any other tips on how to get the steeper points done neatly. What are the values of overhang?
