Hi
I just received my CNC machine (see attached picture) and have been going over it, I have discovered that from the side of the bed to the middle going across the bed, that the bed is not flat and dips down to 1mm-1.5 mm lower than the sides, the manufacturer said that I should use the vacuum bed and the dip in the middle will not be a problem, this doesn't ring true to me, so would like some advice on this issue from some cnc gurus weather or not the bed is meant to be like this for vacuum bed setup, or meant to be dead flat all the way across.
A when I am using clamps I have found I now need to pack the work up level.

Cheers