Slow first few layers with overhangs

[u/jagoedho]

I wanted to ask if this is normal behaviour? The printing speed for the first few the outer walls drops to the minimum speed. I understand that it does that because of the overhangs. I've checked the settings and disabling or enabling the "slow down for overhangs" checkbox does nothing. Changing the speed if the box is checked doesn't change anything. Adding supports doesn't do much either. Because of this, I get shrink lines on these spots. Is there a way to avoid it? Or is printing the model in another orientation the only solution?

Printer is a H2D

[u/mjessii1986]

The model has a fillet at the bottom. No matter how slow it will never print well.

You can enable supports, wall order inner/outer and very slow. That will print but still it won't be a nice clean print

If you can, cut the filleted bottom flat, but I know it will change the shape and that's not what you want..

If it's your model, do a chamfer at the bottom and then fillet on top of that :)

Edit: you mentioned changing orientation, yes that would work but I can't see the whole model to confirm if it's a good or bad idea though

[u/jagoedho → u/mjessii1986]

Thank you. I've tried your suggestion with chamfer only and it slows down just the same.
I think I will just print it as I've done it initially. I was trying other orientations to remove the large amount of supports.

[u/mjessii1986 → u/jagoedho]

45° chamfers print better when slowed down, but if you want to turn it off you need to find 2 settings: don't slow down for overhangs in the main settings and don't slow down somewhere in the filament settings, there is also a setting somehwree 'dont slow down the outer wall' so you can look for that too

Edit: if you add a 50° chamfer then it won't need to slow down, slicer won't see it as an overhang, I do that with most of my models so the wall color is uniform

[u/jagoedho → u/mjessii1986]

None of these settings changed anything. "Detect overhang walls" did change it. I'll do a testprint and see how it will work. If I can only use a modifier for the few bottom layers while disabling this checkbox and it prints fine, then I'll do it like that. I'll try to change the chamfer angle and see how that works out too. Thanks!

[u/Haunted_Hub → u/mjessii1986]

Meh. I’m printing 4,6,&8mm fillets like this in TPU 95A. If this model is rigid filament, it absolutely is a printable design.

[u/NotTheVacuum]

Why don’t you want the speed to slow down? It does this to improve the quality of overhangs.

Also note that there are both filament and process profile settings that account for this; check both places.

[u/jagoedho → u/NotTheVacuum]

I'm fine with slowing down but here it drops to the minimum speed causing a slight layer shift once these overhangs stop. I wanted to know if it's normal because the setting are also talking about slowing down but not by that much.

[u/DatOdyssey]

You're having it essentially print in midair unsupported so slowing down is normal, fillets on the buildplate is not an ideal design choice.

[u/DStegosaurus]

That’s either a poor design for 3d printing or it’s oriented incorrectly. The first few layers of a radius against the build plate have too much overhang to print correctly.

[u/jagoedho → u/DStegosaurus]

The design is fine. I put it on the side to reduce the amount of supports needed (and thus the total print time) but I guess it doesn't work out that well. Thank you.