I've been trying to print a half sphere using Cura and an Ultimaker 3. Because it is used in a friction pairing, it needs to have a really smooth surface, with (ideally) no stair stepping effect.
The first thing I tried was using fine layers, with a height of 0,1 mm. The chosen material was ABS, so it could be chemically smoothed with acetone. After the finishing process, the sphere was looking good on the lower layers, but nearing the top it still had noticeable stair steps. Not only that, but the very top of the print had a bad finish, right where the printer stops extruding. The remaining filament creates a really annoying tip that doesn't get smoothed out with the acetone vapor.
I decided to try out Cura's ironing feature, having had success removing the aforementioned tip with an Ender 3. It hasn't worked out at all with the Ultimaker 3, I get awful finishes when the ironing feature is enabled. I've tried turning the ironing flow off, changing the pattern from concentric to zig-zag and nothing seems to work well.
Recently I've had better looking spheres with a layer height of 0,06 mm, but the top isn't quite working as I would like it to.
Has anyone had similar problems with their finishes? Any tips regarding stair stepping reduction on round surfaces would be very useful.
These are my print settings. Ironing is not enabled, because I haven't had any success with it. Support is enabled because the specific model I'm working with requires it. It doesn't affect the sphere's surface, though. I also have ASA, PLA, iglidur I-180 and Polysmooth at my disposal, with their respective chemicals/finishing tools.
Thank you for your time!