All new FlashForge 3D Printers now ship with 2x Polycarbonate boards as opposed to 3M Blue Painters Tape.
Here are a few things you can do to prolong the life of the Polycarbonate Board.
1. Do not use a scrapper. No matter how thin it is, a scrapper will damage the board. Use a penknife and keep it flat on the board. Think of it as "cutting" the model off as opposed to removing the model from the board.
2. Clean your board with Acetone. This gets rid of any oily residue that may have been left over from the previous print.
3. When prints stop sticking, re-level the build plate and this time make the gap between nozzle and build plate slightly smaller.
4. If all else fails, use UHU glue over the polycarbonate board. But remember to clean it up once in a while, otherwise you'll get very rough finished on your object.
Always remember, sticking too well to the build plate is a better problem to have than not sticking well.