Problem when slicing for print.

Hi everyone!

Now i have created my first ever 3D object!
It’s a sign that i can print and put at my postbox that says, in Swedish, “INGEN REKLAM TACK” (translated: NO ADVERTISEMENT PLEASE")
To get the letters appear as holes was a pain in the neck but finally it looks quite ok, especially when considering that i started blender for the first time two days ago and only had time sitting an hour or so a day.

But i have a slight problem that i can’t understand right now:

I export the file as STL and opens it up in my slicer, FlashPrint (from FlashForge).
I lay the object facing down (so i won’t need any supports) and it looks good. Then i say to slice and then, all the letters are gone!
If i put the base down, the letters are fine but the screw holes are gone!

I have never ever seen this on anything that i have downloaded and printed.

So: Is it something with my object? (probably…) Or is it something with the export of the STL, or is it something with my slicer? (first time ever so, seems not plausible).

I have attached the file. Blender 2.79 for Windows.

If there is something that i have to fix in the file, could you please explain how to do it? Remember, i know almost Nothing about this so be more than basic please. (109 KB)

Unapplied object scale. You’re looking at different size mesh than what the tools and modifiers see.
Ctrl+A -> scale to apply.

The normals (face directions) are pointing to the inside, so you’re describing a form that is made out of air and the printer should fill the rest of the universe. Select all, ctrl+N to recalculate them to the outside.

There are two mesh parts, which have overlapping geometry. Some slicing softwares can interpret intersecting geometry, but this is not clearly intersecting, just overlapping faces. Connecting the geometry is one option to fix it, and also allows to make the model hollow throughout if needed.

Most faces are n-gons, which are faces with more than 4 sides, and they’re concave. If the triangulation fails, it might overlap edges or make them overlap faces. Stl file contains triangles. One option is to select all and mesh menu -> clean up -> split concave faces, and if that succeeds, the triangulation should always work because the remaining faces are all convex. Could also test that with triangulation modifier and enabling wire and draw all edges display in object properties.

File -> save as dialog has a compress option. Use that instead of zip or rar, as it’s transparent to the user


skylt_ja12.blend (157 KB)