I have an arduino powered CNC machine with the Protoneer v3.00 shield. I have a probe setup for auto levelling which works correctly, I get a depth map for the board.
But the issue is that this depth map is created to the point at which the bit touches the board, but the board has some flex in it such that it is raised above the table in the centre. This therefore means that when it comes to milling, any flex in the board gets pushed down by the bit before any milling occurs and so the depth map is not correct as it has not taken account of this.
I realise therefore I need to ensure the board is firmly clamped to the table at all points and so I think a vacuum table is the best option. I have found one which is 210mm x 120mm and has a 10mm x 10mm grid for the vacuum holes (vacuumtablesuk SEAL2 VT2012).
I will be needing to clamp standard FR4 fibreglass PCB board, and I am wondering what vacuum pump would be suitable? I am lost as to how to choose a vacuum pump so any advice and links to suitable pumps would be greatly appreciated!