I am trying to print the Settlers of Catan hex tiles designed by JAWong (http://www.thingiverse.com/thing:26979). I am brand new to 3d printing and am trying to print these on a free printer at my library. I keep running into the same problem. The back and front corners of the hex (regardless of type) will eventually curl up while printing. This causes the hex to fuse with the raft in these areas. Some are worse than others, but I have yet to print one where the raft breaks away totally clean. I'm using a Makerbot Replicator (I think 5th gen) with PLA filament. Any ideas on how to prevent this from happening?