Hello,
I need your help on this. I’m trying to print a led cover / diffuser in PETG translucent clear and after 10-15 tests, I still cannot get rid of the vertical lines. I don’t think it is VFA since I print very slowly.
Here is what I’m talking about:
You can see them a bit on the left and right and those lines show when light is diffused. Is it a limitation of the printer (the stepper motor?) I did all the calibration, check the belt tensions and alignment (I even tried different tensions).
I also found a limitation in orcaslicer / bambu studio. Arc fitting doesn’t work in vase mode because it uses the Arc Welder script and by default the z is not enabled because some printer doesn’t support different Z with G2, G3 commands. So I ran the arc welder script manually to enable z
-z - If supplied, 3D arcs will be allowed (supports spiral vase mode). Not all firmware supports this.
and it did improved the result but not completely fixed it.
any other suggestion I could try? Does any of you have similar issues with slow print?
Thank you
Did you import the object as an stl or use a built in primitive?
I have found a 3mf export from CAD and subsequent import to give the best results.
If it is VFA, you are likely to see a variation of the pattern around the cylinder. If not, it is likely a geometry export/import artifact.
Finally, I have found white to make a more appealing diffusor tgan transparent, but it really depends on the use case and personal prefference.
for the geometry I tried primitive, step, and stl, I tried 100k geometry for a 100mm diameter circle which is a bit crazy since primitive is around 3k.
I played with the precision and with arc fitting it change everything to arc anyway.
At first, in the slicer you could see the vertical lines when the arc fitting wasn’t working on vase.
But after running manually arc welding on the gcode, those line were not visible anymore in the slicer.
I did tried at first white PLA because I already had a spool. I don’t mind trying white PETG, maybe with a PETG HF I could mitigate the issue with higher speed, but still I’m a bit disappointed of the printer at that price.
it is my the first time trying to build a diffuser, so I haven’t done much tests with different filament.
There’s another simple check you can do on the prior print. If the ripples have a pitch of 2mm, it is possible that they are VFA artifacts and therefore due to the printer.
If the pitch is different (it looks smaller to me in the pic), it is likely the model geometry so that a 3mf CAD export can help.
PETG has its own tricks and translucent again a few more. PETG rewards printing slower and using the Generic PETG cooling settings. It also needs to be well dried.
PETG Transparent shows VFA’s better than most other materials and there are special settings for best translucency. But first, it would be good to get a good geometry print to see if you want that or if you want to go for a more opaque diffusor.
I would appreciate if someone can test this. It is a small test, only 4.20g. I did not enabled vase because, arc fitting doesn’t work otherwise and the geometry issues would show up. So this test will have a stitch, which is fine. test-cylinder.3mf (38.0 KB)
I have the same 2mm a lot more visible on transparent filament, I also tried in grey pla, they are also there but almost not visible, I guess the PETG transparent amplify the issue. I don’t know if the 2mm lines are coming from the belt teeth or the 1.8deg stepper motor.
I was able to reduce by a lot the vertical line when printing at 20mm/s. but when I tried at 0.08mm layer height I did get those lines and it was very narrow. I think it would be related to the extruder this time. Because when I try 0.16mm layer height, it is fine. The next thing to try is 0.08 again but with a higher line width like 0.6mm, otherwise I don’t have other hotend to try
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