One thing to consider though if dimensional accuracy is important.  The first few layers, especially the first one are heavily compressed in order to "press" the plastic into the built platform for adherence, so you'll find that the bottom layer will squish outwards, leaving a bit of a lip on that edge, while at the same time being thinner than what it should be.

The amount of deviation is dependent on a lot of things including the actual gap between your nozzle and the print surface, the flow, speed, etc.  Simplest way to find out is to print a test piece, usually a cube of known dimensions, and measuring it after wards.  This way, you can modify the piece you're printing in the CAD program to account for that deviation.

I've bought a Qidi Tech (Flashforge clone) & have had medium success with my first few prints.

I need to prototype simple plates & brackets which will eventually be CNC'd in aluminium. Phone Ringtones

The surface finish I've got off my first print is impressive but ruined by the raft. What should I be doing in Makerbot Desktop to give me a raft that is easy to break away yet leaves me with a good bottom surface. Even something that can be sanded would help?