Vertical ripples/horizontal lines/Z-banding
Hi everyone. I'm currently reprinting some parts of my VC4 using eSUN PA6-CF with a SiC nozzle.
I have some strange horizontal lines (vertical ripples). See picture. The peak distance is around 1mm. The lines are going around the complete part, so it's not an X or Y layer shift.
For me it looks like the flow for the outer perimeter is changing with height. (which cannot be IMHO)
I have redone PID for hotend, flow and PA is calibrated.
A calibration cube does not show those lines.
Any ideas what else to check or where the problem can be found?
3 Replies
I just printed the same part using JAYO PETG filament. It shows no horizontal lines now.
So I guess it's not an issue caused by hardware alone and has to do something with the filament.
I measured the thickness of the filament for around 1m.... Diameter does not change.
I did some more test prints (simple cubes) with varying print parameters (Number of walls, Speed, etc.).
My first print was with two cubes at once and the second print with one cube alone.
The distance between the ripples doubled from two cubes to one cube, which means there is definitely some problem with the filament...
Z-axis i definitely not the problem otherwise the distance between ripples wouldn't change...
I remeasured 1m of filament (each 5 cm). Diameter stays between 1,7 and 1,67 mm, so it cannot be excessive material. Maybe varying density?
Or does it have to do something with hotend and 0,4 nozzle?
Or did I just get a bad spool? (Well I ordered another one to check this)
Tried also with print speed down to 100mm/sec, did not help either...
Print three cylinders, place them where the head measures for tri level.
Are any one of them worse than the other?
Hmmm, very strange... All three cylinders look the same and without ripples...
Only difference: The filament was not totally dry and cold. Before I dried it for at least 6 hours and used the still warm spool...
But this should not make a difference regarding the ripples, right?
Nevertheless: I started drying and will retry printing the cylinders. Let's see if this makes any difference...
Again all three cylinders look okay and no ripples.
Then I tested again with cubes at the exact same position (tri level measurement position). The cubes now look also okay with almost no ripples (only minor, barely visible and random; I'd consider them normal, maybe double layers caused by warping)
Then I tested with two cubes in the center of the plate. The ripples are visible now again.
This really confuses me... Maybe they are visible due to the matte finish of this filament. In fact it looks worse than it is?
Today I also did a larger print with PETG in the center of the plate and there were no ripples visible at all. I checked with a knife-edge square..