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Vitt1812

Top layer is smooth and Bottom layer is not and looks ugly

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Hi All,

I need help in fixing my problem regarding bottom layer looking ugly.

Top layer is smooth and perfect. and it feels like bottom layer lines are not merged.

IMG_0386.thumb.JPG.8f12322eac0a7d04bc51f0792fa496e3.JPG, IMG_0387.thumb.JPG.30b04654a1092023a17b139d1112d2be.JPG

Layer height 0.1 mm; Bottom/ Top thickness 0.8 mm; Initial layer thickness 0.3 mm; bottom layer speed 30 mm/s;

Bottom was printed on the support structure. But I have seen similar effect when I print it on the Raft as platform adhesion type.

IMG_0386.thumb.JPG.8f12322eac0a7d04bc51f0792fa496e3.JPG

IMG_0387.thumb.JPG.30b04654a1092023a17b139d1112d2be.JPG

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Hi IRobertl,

Thanks for your reply.

I understand what you are trying to say.

Please check pictures below. This was my earlier print with Raft as platform adhesion type.

In this also Top and bottom layer looks different. Different parts were printed and assembled.

In the picture red marked faces are bottom layers, blue marked face is top layer and black marked is portion of Raft face towards build plate.

Can this be because of distance between bed and nozzle?

Capture2.JPG.2706ff3fdf9b03fbe2fd9a841d3eac8d.JPG, Capture1.JPG.1cb7f907ce5aa220b2153378d757e294.JPG .

Capture2.JPG.2706ff3fdf9b03fbe2fd9a841d3eac8d.JPG

Capture1.JPG.1cb7f907ce5aa220b2153378d757e294.JPG

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Have you tried printing the parts directly on the glass plate, without raft or supports? That should give nice flat bottom layers.

If you print on a raft or on supports, the first layer of the model will always look ugly: there has to be a gap between supports or raft, and print, otherwise you can not remove the support from the model. But that makes the first real model layer sag and distort, thus ugly and with holes in it.

If you don't mind assembling, try modeling the parts in such a way that every part has one big flat plane on which to print it. Else, it is best to design your own supports, or play with the support parameters (closer together, smaller gaps), for finer results.

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The parts I print lately are semi-circular and curved, so I have to use a lot of support material. Making the bottom smooth can be tough, no matter which support type you use. (In my case, some low grit sandpaper helps pry off some stubborn support pieces)

Where you have a flat piece, you should be able to get a great, smooth result from the glass/heated bed.

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...

Making the bottom smooth can be tough, no matter which support type you use.

...

 

Yes, indeed. I also tried lots of different custom support designs for smoothest bottoms.

What works best for me is:

- A thin but solid bottom layer (e.g. 0.4mm).

- Then a sort of tree-like scaffold, which leaves me lots of room to use pliers or hooks later on to pull the support out.

- Then I split the tree in thinner branches.

- Next again a thin solid layer, just below the bottom of the real model.

- And finally small ridges of 0.5mm wide, separated 1mm.

- And a gap of 0.2mm (minimum, for very fine models) to 0.5mm (for bigger models) between these ridges and the real model.

Then the bottom of the model is still not smooth, but at least way smoother than with standard supports (of Cura 14.09, haven't tried later versions yet).

Smaller gaps between the ridges and model give smoother bottom, but make the support more difficult to remove.

Also for supports in-between model parts, I use a similar approach, as shown on this test piece, where I tried out various gap sizes.

support_test5b.thumb.jpg.cec41ea5bad83bd827d1a52732b93e31.jpg

support_test5b.thumb.jpg.cec41ea5bad83bd827d1a52732b93e31.jpg

Edited by Guest

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The parts I print lately are semi-circular and curved, so I have to use a lot of support material.  Making the bottom smooth can be tough, no matter which support type you use.  (In my case, some low grit sandpaper helps pry off some stubborn support pieces)

Where you have a flat piece, you should be able to get a great, smooth result from the glass/heated bed.

 

If you can try a 0.8mm nozzle. Unbelievably the difference on overhangs is stunning. No support used.

5a3311cfcc3ff_greyoverhangbad.thumb.jpg.b78c8add536c35faeed2ff5208c5c12b.jpg

5a3311d0050e6_greyoverhanggood.thumb.jpg.bd8b35c20257905f38bc287daeff6a2a.jpg

5a3311cfcc3ff_greyoverhangbad.thumb.jpg.b78c8add536c35faeed2ff5208c5c12b.jpg

5a3311d0050e6_greyoverhanggood.thumb.jpg.bd8b35c20257905f38bc287daeff6a2a.jpg

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I have a similar problem, currently I'm on version 3.0

I was puzzled by this problem, and finally discovered that Cura removes the very bottom layer. The part on the screenshots should have the bottom layer exactly like the top one, but, it removes 1 layer, and reveals the layer where the lines are skipped one after another.

Top layer, as it should be:

cura_top_layer.thumb.PNG.85ee8d299887cdd440673f1180df43ca.PNG

Bottom layer, 1 is removed

cura_bottom_layer.thumb.PNG.7f5abee5837bd444f08e4509b1c8003e.PNG

Nowhere in the settings could I find anything related to the missing bottom layer.

I print with Anycubic i3 mega (RepRap gcode style), and thus decided to use another printer settings. I went for some of Ultimakers, expecting the settings to be more default-like.

What I saw that for Ultimaker, the top layer was removed together with the bottom one.

Ultimaker 3 top layer:

cura_anycubic_top_layer_default_settings.thumb.PNG.34ad8497e60ec9e326cdcac0bcbf6d91.PNG

Is there any way to have controls of the bottom and top layers removal?

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