Printhead grinding on ABS infill.

Hi,

I'm having an issue when I'm printing with ABS. The infill on my prints seem to cool slower than the outlines of my prints and therefore shrink less. This means that when my print head goes back over of the next layer it's grinding over the print which I'm worried will damage my machine. It also breaks the prints off the print bed if the item is too tall.

Has anyone else had this issue and could suggest a solution?

Im using a Da Vinci Duo 2.0 with Repetier firmware, prints sliced with Slic3r at 20% infill.

If i understand what your saying, the print head is grinding over the dried print as it warps due to the infill cooling slower than the outside?

In most slicers you can edit the infill print speed. Perhaps lowering this might help. Also what temperature are you printing at? A lower nozzle temperature for the entire print might help.