cura incorrect cube slicing

[seredos 1]

Hi, I've recently started working with 3d printing and have created a small object in Blender, which I'm trying to print using cura (printer: anycubic i3 mega s).

 

It is a simple cube which has text on each side. In Blender and Cura the object is displayed correctly. However, in the preview version, the top and bottom of the object are not labeled. - So far, the slicing with Cura has worked smoothly and I am now a bit puzzled why it simply omits the font.

[Smithy 997]

How deep is the cut out of the text? 

Maybe is is not enough for the layer height of 0.2m but I am just guessing.

 

Or your object itself has some problems, not really watertight or something like that.

[seredos 1]

The cube itself has a side length of 2.5 cm. The text currently has a depth of 0.5 mm. However, I had already tried a depth of 1 mm, which led to the same result.

 

If I rotate the cube by 90 degrees around the Y-axis, so that the upper side of the cube is no longer on top, it is cut correctly.

 

However, the text that is ultimately at the top or bottom is never cut correctly.

text_cube.stl

[gr5 1,734]

I took a look.  The normals for the letters are all backwards.  Facing in towards the air in each letter instead of in towards the plastic.

 

In STL files it's an unordered list of triangles and each triangle has a "normal" which tells the slicer which side of each triangle faces plastic and which side faces air.  You have it backwards.  Cura gets confused and thinks the letters should be filled in.

 

Blender has a feature to fix the normals - 

Quote

if using blender - here's how to fix your model
I went into edit mode with the object in Blender 2.83 and pressed "a" which selects all faces / vertices / edges, depending on what select mode you are in. The entire object should be highlighted. I then went to "Mesh" (see images), went to the "Normals" section, and selected "Recalculate Outside". This probably will not fix any edges that are not merged, but it will fix the faces that are inverted on the object. 

 

You can also install the cura mesh tools and fix the normals that way but I recommend fixing them in blender.

[seredos 1]

Arrgh... it's been so long since I've made anything with blender.... I often had to recalculate normals. And still did not get the idea that it is because of it.

Now it works... thank you 🙂