Vaccuum table holes

Hi Group,

I am working on the table/platform of a router and want to hold parts
with a vacuum.

Can anybody guide me along the right path ?

it seems that a vacuum would remove pressure from one side and the
air pressure would the force the part down. At the same time, the
surface area that the part has in contact with the table would offer
friction also.

more holes, more pressure less friction, less holes, less force
greater friction.....

I want to trim the edges of sheet metal parts, aluminum, so the
cutting forces would be on the side trying to slide the part on the
table.

TIA
Dave