Bumps on the outside of prints with internal solid layers  

Bumps on the outside of prints with internal solid layers

Hello all,

Will try to explain this the best I can. Where a print has a change between it being normal infill at say 10% and a solid layer, I get ridges on the outside of the print when sliced with the prusa slicer (this does not happen with say simplify3d, so I don't think its a machine issue). You can see this ridge here:

This test print is designed as a box with the top off, so it has an internal cavity:

and that ridge happens as the print transitions from this stage:

through these layers:

As I say, this doesn't happen with simplify3d (I dont own a copy myself so can't "just use that instead"), does anyone know whats causing it or what settings I could play with to rectify it? The issue doesn't seem too bad in this test object, but it can get bad with multiple transitions and can require adding extra clearance between parts that need to slide against each other etc.

Thanks

Charles