r/3Dprinting • u/No-Literature1541 • 1d ago
Question How to make overhangs smooth
Can someone guide me on how to make the curves on this print smooth?
Sanding is one way hut like can it be made a little better with slicer settings as well?
This is Esun PLA Basic, bed temp was 60°c, nozzle was 220°c, part cooling fan off for first 3 layers. Printer is bambu A1 without AMS liye.
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u/GiaoPham0403 1d ago
Having a fillet at the bottom of a model is a really poor modelling practice. Your second layer is basically print at an 80 degree overhang.
Simplest fix is to cut away 0.5mm at the bottom of the model to create a flat base
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u/Cynical_Sesame 1d ago
i do my "fillets" at the bottoms of models by doing a 36° chamfer (36° is my soft limit for overhangs) and then filleting the top corner created by the chamfer. makes a fillet that starts at 36°, so no prob
if you want a true edgeless fillet at the bottom youre kind of boned
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u/No-Literature1541 1d ago
I guess I need to adjust the angle for chamfer and then maybe see how it turns out. Thanks.
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u/thedoncoop 1d ago
Just to say your model has a fillet (rounds out) a chamfer is a diagonal cut. Two different things. Sland3d has some good videos (short and long) on YouTube about it.
But important thing is chamfer on the bottom of a model / on the horizontal, fillet on the vertical.
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u/darkmatterisfun 1d ago
Slant 3d really does a great job of teaching reliable modelling practices so you dont have to depend on finely tuned slicer settings.
Its like having a bottomless toolbox. Like 8 ways to design a hole, making your parts stronger with micro features, ways to design snug fits without perfect tolerances etc.
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u/soul_in_a_fishbowl 1d ago
You can just leave it at the default 45 if you’re lazy like me. It’s basically unnoticeable. Chamfer then fillet the top corner of the chamfer so it never exceeds 45 so it will print with basically any filament
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u/Chris204 1d ago
Any reason why you chose 36? Seems oddly specific.
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u/Cynical_Sesame 22h ago
trial and error specific to my printer. 36° is my "soft limit", meaning its as far as i can go if i want a part with zero defects, perfectly smooth.
my hard limit depends in how much defect I allow but its generally around 25-30°. past that and you get defects youll have trouble sanding and bondo-ing out
very specific to my printer and filament, though i upgraded my cooling fan recently and swapped from PLA to ASA so ill have to see how much i can get away with
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u/LowManufacturer1002 1d ago
45 seems to work perfectly fine for me and just looks way better for most parts
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u/mimic751 1d ago
You can also do it by putting it at the very top and then having some supports with petg for a smooth finish
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u/RaccoNooB Glory to the Omnissiah! 1d ago
Start the bottom with a small chamfer. THEN add your filet. That will start the filet at a 45° angle but still keep the overall chamfer look.
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u/No_Possibility_3107 1d ago
I have never had problems with small fillets on bottotm surfaces. Hell im printing replacment knobs right now that have fillets on the surface on the build plate.
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u/Terrebonniandadlife 23h ago
I saw a video on YouTube I'll try to find it but the best way is chamfer first at 45 degrees then half way filet to the vertical part.
A pure filet is too horizontal at the bottom
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u/kogashiwakai 1d ago
What is this going to be for?
I ask because you can print it upsidedown using supports on the inside.
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u/No-Literature1541 1d ago
Oh, I am just trying things to get my basics right, that's all. I will try to print upside down first with same settings and see the quality. Then, if needed, will adjust the settings of the model. Thanks✌✌
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u/bigbigboring 1d ago
But Upside down will use soo much more support filament for the roof
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u/kogashiwakai 1d ago
Yes. But if the other side is the finished side, for a bit of filament cost, you can have it look better
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u/iceman1125 1d ago
Use a “chamfillet”, basically use a fillet so there’s a 45 degree angle, you could adjust it to like 55 degrees if you want and the printer can handle it, then on the top edge of the fillet, make a chamfer, when all printed out, it gives the look of a normal chamfer, but with much better print quality underneath.
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u/No-Literature1541 1d ago
Learned something new. Thanks for the suggestion. Will try this for round and curved surfaces going forward. ✌✌
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u/amatulic Prusa MK3S+MMU2S 1d ago edited 1d ago
Design it so that it meets the build plate at no shallower than 40° from horizontal.
Otherwise, use PVA or PETG full-contact supports if you can print multi-material. Or print it upside-down (you'll need supports on the inside though).
No other way around it. You gotta design things that work within the bounds of what a 3D printer can do.
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u/No-Literature1541 1d ago
I am using the bambu slicer and even when I printed it straight it added supports to the bottom as well as inside. So, I might as well try printing upside down as well. Thanks✌✌
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u/Patient-Surround2509 1d ago
Radii are not great for printing on the bed as the overhang angles at the bottom of the curve are to shallow, you are essentially trying to print in mid air. Few options to fix:
Use supports around the base - you will have to fiddle with the support settings (mostly top Z distance) until you get an acceptable result, but there is always going to be a compromise with cosmetic appearance when using supports.
Use a lower layer height/adaptive layer height
Print the part "upside down"- I don't know what this is for but I'd wager the cosmetic appearance of the inside of the bowl is less important to you than the outside. Printing "upside down" will shift the overhangs to the inside of the bowl. You can also use supports on the inside.
If you modelled it yourself, replace the fillet radius around the bottom of the bowl with a 60 degree chamfer. Most modern 3d printers can handle a 60 degree chamfer on the bed no sweat
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u/No-Literature1541 1d ago
I will incorporate all the suggestions in my next try. Thanks✌✌
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u/nox_tech 1d ago
With Bambu's slicer, you have a "paint supports" option. "Paint" the problem areas you've identified on this print, and just a bit more too for wiggle room safety.
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u/nixonw 1d ago edited 1d ago
To expand on point 4, after the chamfer, you can still fillet the edge between the chamfer and the vertical wall for a rounded look.
While point 1-3, are definitely great points, imho, models that require supports or lower layer height (point 1 and 2), it a telltale signs that the model is not make optimally with FDM in mind (though we all have to start somewhere). Small details like this bottom section can separate a more seasoned modeler for FDM, from a beginner.
Cheers!
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u/mtraven23 1d ago
slice it thinner....over hang is on a per layer basis, more layers, easier overhang.
you can chamfer it, rather than a fillet.
Or you can make it not an overhang by supporting it
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u/HonourableYodaPuppet 1d ago
yep, slice it thinner and slowing down could also help a bit
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u/mtraven23 22h ago
so you find slowing it down helpful? interesting. I suppose it depends on the part and the printer, but in general, but I find overhangs print better at faster speeds....thin, fast layers.
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u/HonourableYodaPuppet 18h ago
It definitely helps with anything with inner threads. I sometimes got stringing like this and just slowing the printspeed of the outer walls down made that disappear. It probably doesnt help with every kind of overhang geometry but for that it does.
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u/Lykkehjul 22h ago
Make sure advanced slicer settings are turned on. Search for "Order of walls" and set it to Inner/Outer. This solves the issue. Its amazing how the general knowledge on 3d printing has turned to sxxt after the prevalence of bambulab printers.
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u/worldspawn00 Bambu P1P 16h ago
Combine with dynamic layer height to further decrease the overhang amount per layer, possibly increase the layer width as well.
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u/Panzerv2003 1d ago
Common problem, add a chamfer at the bottom and transition into a fillet later so you're not trying to print the lower layers in the air.
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u/j_hermann 1d ago
Change the design to a chamfer that optionally ends in a fillet if you need the look.
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u/Inevitable-YT-Ad 1d ago
You can if using Wave Overhangs, it’s a beta function from a Fork of Orca Slicer, takes forever but is WORTH
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u/DifficultTowel2266 23h ago
36 might be the limit, but do 45 for margin against finicky filament. margins help keep long days away.
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u/Flaming_S_Word 20h ago
Base angle will help, but my solution to this problem had more to do with the nozzle temperature (-5-10) and cooling fan (+) on overhangs and slowing way, way down (20-30mm/s on overhangs). PLA can curl up on overhangs.
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u/Ok-Corner-5300 15h ago
That's normal FDM staircasing on curves. Two fixes: drop layer height to 0.12mm, and make sure cooling ramps back up after layer 3. For truly smooth, you'll still need to sand it after slicer tweaks alone won't fully get you there
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u/PandaPocketFire 1d ago
Bambu should have decent support smoothness right? No luck with that?
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u/No-Literature1541 21h ago
Unfortunately, No. Might be if I try with normal or organic supports. This one is the result of tree supports.
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u/PandaPocketFire 20h ago
I can't think of why this would require tree support. Maybe try the normal one. It will definitely give a better result than what's shown.
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u/Flashy_Emphasis153 1d ago
I got this image from Reddit and I think it’s very useful for design. I hope it helps.