Cartesian Bot Variations

Weight reduction

Using M3 rods (instead of M8) for the diagonals will reduce the total weight of your RepRap darwin by a couple of kilo's. I don't think this will make much difference in terms of rigidity. If you want to have a more mobile RepRap, this will help a out! You need to add two washers to stay compatible to the [diagonal tie brackets].

Alternatively, we could design printable diagonals. They have to be pretty thick, because plastic stretches a bit. Even a tiny bit of stretching makes the machine less accurate.

Heated base plate

The folks at [Metalab] have had a lot of success with reducing thermal distortion by building on a [heated base plate]. See that link for details.