Banding on my prints
What's happening here ?
I'm getting banding at certain layers on my prints.
I tried a few times, but I get the same result.
The prints were done using PrusaSlicer 2.o.o - 201905201652, while the bottom one was done using Cura 4.2.1.
You can see the difference between the slicers.
They were printed upright and along the x axis.
Regards
Michael.
RE: Banding on my prints
Check the grub screw on the bondtech gear on your motor shaft for a tight fit against the flat part of the shaft. Irregular extrusion can come from a loose fit of the gear.
RE: Banding on my prints
Those part photos look like a side view, not the top view. If so, then then problem is bed adhesion: the parts are warping and lifting off the bed and when they do this, it compresses layers and plastic oozes out the side of the part (it no where else to go when the part is pressing up against the nozzle).
The middle bands are probably due to another part on the bed that isn't being shown, that changes the layer print time. Slicer will slow print speeds when a layer takes less than 20 seconds to print. This speed change affects perimeter quality.
RE: Banding on my prints
timo-m
This doesn't explain why the problem happens at the same layer height on all the prints.
And why it doesn't happen with the Cura version.
tim-m30
Yes, they are side views.
I printed these as a single item, and some with a skirt. So bed adhesion isn't the problem.
I did a test print by printing 6 of these with varying lengths, and they all had the banding.
I did another print yesterday, and the bottom quarter of the print had a ripple effect with the ripples spaced about 5mm apart,on both sides of the print.
Would the thickness of the part have anything to do with it, as I printed a test cube, and a torture test model and they didn't show signs of the banding.
RE: Banding on my prints
tim-m30
I printed these as a single item, and some with a skirt. So bed adhesion isn't the problem.
Actually lifting - or warping - can do some odd things like what you are seeing. These two areas are exactly what warping does as the part lifts - the nozzle gets buried into the part and plastic extrudes horizontally. The images are rather conclusive. Though if you said the second one is brim residue...
As for the other lines, is there any structure on the back of the part? Or inside the part? If you can post the STL (zipped of course), it would be helpful for understanding what might be going on. After all - people print squares and blocks all the time. And most us of don't see what you are seeing unless there are other things happening.
A few of us did some rather lengthy testing for similar linear artifacts - bulges - caused by wall width, print speed, print direction. Bob has a few pointers at minimizing them by controlling wall thickness. Probably worth your reading.
RE: Banding on my prints
Here's the STL file of the test item I'm trying to print.
If anyone would like to give it a go and see what results you get.
It's the legs of a colonnade, so that's why it needs printing in this orientation.
RE: Banding on my prints
Can you say FINITE RESOLUTION at the same time as FDM?
RE: Banding on my prints
So here's the part: notice the obvious "artifact" isn't an artifact. It's in the design of the part.
The full print:
But what is happening is the part tapers to a knife edge. FDM can't print these types of edges well. The step is where the slicer changes from two perimeters to one perimeter.
RE: Banding on my prints
Here's a better view of where Plicer is reducing from 2 to 1 perimeters:
RE: Banding on my prints
That looks like the same result I got.
it seems the full model prints better than the test piece.
I tried it using Cura 4.2.1, and it seems to handle it better.
I don't get the step in the surface that I do with the PrusaSlicer version.
RE: Banding on my prints
If you get a chance, post up a preview of Cura's slice where the parts goes from two to one perimeter extrusion.
RE: Banding on my prints
Here's a comparison of the PrusaSlicer results with the Cura results.
The Cura one is the top one.
And screen captures of both programs after slicing.
RE: Banding on my prints
Looks like you should stick to Cura for that print. Are the other parameters the same between the two prints? From the stairsteps towards the corner of your print it looks like the Cura print used coarser layer heights?
RE: Banding on my prints
Cura is simply chopping off the part early to avoid the thin wall problem in some areas, and thickening the walls in other areas.
Cura
Slicer
