S3D creating unwanted solid layers in a hollow part

[Stefan_Koch]

Hi everybody,

I´m printing a rather large hollow part (39 cm high). As the part is hollow, and the geometry allows it, I´m printing without infill or support. I´m not using the "spiral vase" function, however, as the .stl came already hollow, and the wall thickness is more than just one perimeter.

For some reason, when calculating the gcode, S3D puts in three solid layers at seemingly random intervals. At layer no. 627, 657 and 917 of 987 layers. I don´t see a system here, and the option to create a solid infill every xx layer is not activated.

Here´s layer 626, still everything hollow and fine:

And then there is the mysterious solid layer:

These solid layers actually cause the print to me ruined, as most of the filament falls to the bottom, but some keeps stuck on the rim, bends into every direction, and then jams the hotend on it´s next pass.

Any idea what causes these unwanted solid layers ? I can of course edit them out in the gcode, but maybe there is a simpler way to avoid this happening.

I´ve attached the fff file:

S3D-3PO-ABS-1mm.zip

(2.31 KiB) Downloaded 200 times

Thanks in advance for any input

[KC_703]

Check that the model is manifold, self intersecting surfaces, or reversed faces. Problems in the original STL file can create weird slicing artifacts...

I didn't bother to import the FFF file (profile), can you post the original STL or factory file?

[jimc]

Check that the model is manifold, self intersecting surfaces, or reversed faces. Problems in the original STL file can create weird slicing artifacts...

I didn't bother to import the FFF file (profile), can you post the original STL or factory file?

x2

thats a sign of a model problem. run it through netfabb and reslice it.

[Tetraodon]

I'd suspect a model problem too. Are you by any chance running multiple processes?

[Stefan_Koch]

Well, when I "hollowed out" the originally massive part (with Netfabb), I used the automatic repair funcion there, as hollowing always creates small errors. But I can check the part again in Netfabb.

I suspect indeed that the artifacts have something to do with the "hollowed out" part. I sliced the massive part version yesterday, with just perimeters, and no top layers, and it came out fine in the preview. The actual print will happen tomorrow after work.

Thanks for your input so far !

Stefan