Rubber Baby Banana Bumper

I wouldn't say this is nearly as convenient as the plastic shields Next Thing offers for the CHIP, but if you need something a little more rugged and/or needs to be mounted to something, this should serve as a decent alternative. The tolerances were kept fairly tight for the sake of the rubber filament it's intended for. Similarly, the tiny recess in the corner will let your screw of choice get a good grip. Even without it, the one I printed on my M3D keeps a firm hold on the board and wouldn't fall out even with a decent shake.

Infill was about 40%. Sorry for no exact figures; I'm still using the default software M3D provides (haven't tried Cura yet). However, I certainly do not recommend a raft as this gives you a nice, broad, flat surface to apply your favorite adhesive.