How to make the top of a hemisphere smooth?

[ultimaker_user 0]

Hi, I printed a hemisphere but from about 2-3mm towards the top, it does not look smooth nor as uniform as the rest of the print. From what I know, adaptive layering is already set by default. Does Cura has other smooth functions? Could you please advice on how to make the top and the whole sphere perfectly around and smooth? Also, where is the Adaptive layers threshold? It seems to have disappeared. Thanks

Edited April 1, 2021 by ultimaker_user

[Torgeir 242]

Hi @ultimaker_user,

 

"use adaptive layers" is not set by default, you need to select it yourself.

Go to "preferences", then select settings and then select; "check all". Close preferences.

Next, select "printer settings" go to "experimental" and select; "use adaptive layers".

That's all.

 

Thanks

Torgeir

Edited April 1, 2021 by Torgeir
More text.

[ultimaker_user 0]

Thanks. When I checked this option, the check marks were already there. I guess I might have checked them few months ago. If I use adaptive layers, do values in Quality->Layer Height and Initial Layer Height have an effect on the prints? If I want only the first layer to be 0.2mm but the rest to start to have lower adaptive layers, what shall I do?

 

Besides this function, that what else can I do to make the prints smooth?

Edited April 1, 2021 by ultimaker_user

[Torgeir 242]

Well, this depend a little.

You can try to print using "spiralize mode" (single wall), but then you will not have a full covered top (about max 95 deg).

Using this simply leave a small hole in the hi point.

 

To print it fully closed, you will need to use a gradually thicker wall as you approaching the top.

If you need it to "be/look" nice at the inner wall as well you'll need support.

 

But it will be better if you have a dual nozzle system and using PVA or "break away" as support.

 

The way you design you "dome" and how it's size matching nozzle width also count in order to improve here.

 

You'll need to try and tune your setting / material type for best result here.

 

Good luck

Torgeir

 

 

 

 

 

 

Edited April 1, 2021 by Torgeir
Error corr.

[GregValiant 1,250]

Well @ultimaker_user, as usual, Torgeir gives good advice.  You can try his methods to see how much you can improve the finish.

 

Unfortunately,  FDM uses layers to put the plastic down.  Those layers are going to have a thickness.  Yes, you can lower the layer height to .08 (or if you're really brave, maybe .06).  There will still be steps...they will just be lower and therefore less noticeable.  If you want it smooth you need to hand finish it.  You can get sandpaper down to 4000 grit at an auto-parts store or you can use a high filling primer and paint to get it perfectly smooth.

 

Right now I'm printing a model that is essentially a 100mm diameter ball.  I'm using adaptive layers but there are going to be steps.  The larger the radius, the more pronounced the steps.  It's the nature of the beast and in the end that puts an absolute limit on the finish you can get from the machine.