Cura 2.5 holes in surface where cylinder mates with cube

[brickZA 0]

Hi,

I made a test model where I imported an octagonal pin with a hole in the middle (Cham10mmhexholepeg.stl from thing:1692326) into FreeCAD and then mounted it on top of a cube.

When slicing this some weird artefacts appear on the top surface of the cube where the pin attached. In the layer preview there are some holes and also places where infill intersects with the top layer.

As far as I can tell my model is solid and watertight and fine in every other respect I know how to check It also seems to slice OK in slic3r 1.2.9. For reference, here are my files: press_fit_test_pin_cura.gcode, press_fit_test_pin.stl, press_fit_test_pin.fcstd

Am I doing something wrong, is the expected behaviour, or a bug?

[burtoogle 500]

The reason that is happening is because the skin is being removed where there is infill above. The infill above is inbetween the inner and outer walls of the hexagonal pin. As you are using Cura 2.5, enable the new "Expand Skins Into Infill" option and that circle of infill will go away. The ability to remove infill that is below features that lie on top of horizontal surfaces is one of the reasons this new feature was created!

[brickZA 0]

Thanks, the "Expand Skins Into Infill" option seems to fix it

The reason that is happening is because the skin is being removed where there is infill above. The infill above is inbetween the inner and outer walls of the hexagonal pin.  As you are using Cura 2.5, enable the new "Expand Skins Into Infill" option and that circle of infill will go away. The ability to remove infill that is below features that lie on top of horizontal surfaces is one of the reasons this new feature was created!