Prevent thin layer on iPhone cases

[soapergem]

Hi everyone! I just finished building my first 3D printer ever earlier this week, and am hungry to print all sorts of things. The one I built is called a Rigidbot. I've been trying to print some cases for my iPhone 5 that I found on Thingiverse, but I'm running into a small problem. Many of these cases have holes in them by design, spots where the camera can peak through for instance. But my slicing software (Slic3r) is filling in these holes with a thin layer of plastic. When I first load the STL file into my printing program (Repetier Host), it looks like the holes are fine. But as soon as I run the slicer, it's obviously that it's adding a thin layer there instead of letting it remain empty. I assume this is a setting in the slicer that causes this? Could anyone point me in the right direction on how to ensure the slicer software doesn't fill in these empty spaces with unwanted thin layers of plastic? Thanks!

[LambdaFF]

2 questions :
- 1 / are you sure this is not support for another feature ?
- 2 / if it's "hair"-like, you can correct that with better cooling (for PLA only) or modified retraction settings.

Obviously, a photo would help.

[tpete61]

Make sure the slicing software is not setup to print a raft, that might be the problem.