Print horizontal surfaces (not solid)

[MarcosC 0]

Hello!

I´m trying to print a stl file made of surfaces. I've chequed:

Surface model: Surface

Print thin walls

Layer height_ 0.2

Vertical or so walls are OK, but horizontal surfaces are not printed. Angled faces are not sliced properly. There are gaps between layers. Wider gaps as more close to horizontal.

Tryed Surface mode: both, but then nothind is sliced.

No changes in Top-Bottom options: 0.8 yhickness, 4 layers...

Thanks in advance!

Show you an example with a test file: 

[GregValiant 786]

"Angled faces are not sliced properly. There are gaps between layers. Wider gaps as more close to horizontal."

That's the nature of FDM printing.  The closer you get to horizontal the farther apart the "steps" between layers get.  The formula is TAN(90-Angle) * Layer Height = Step Distance.  When the step distance gets farther apart than your line width the model starts to fall apart into strings as the steps don't get glued together.  It happens on that model because the surfaces have no thickness.  On a regular model there would be material below to fill in the gaps.  It would still need support though.

If you have a surface or overhanging feature that just happened to be 26.565° from horizontal and your layer height is 0.2mm then the formula says:  TAN(63.435) * 0.2 = 0.4.  If your line width happened to be 0.4 then you need support because the outside wall extrusions no longer touch the one below.

 

Your surfaces are infinitely thin.  If Cura doesn't slice right along the plane of the horizontal surface it could be missed and you get what you see.  If you play with the "Initial Layer Height" you may find a number that allows the horizontal surface to be sliced.  It still won't print as the whole thing is over air and so it would need support.

 

 

 

[MarcosC 0]

Ok, thanks!