I have a 5'x12' vacuum table for my CNC router that I generally keep topped with a 4'x8' spoilboard for sheet cutting. I am cutting some 2" wide rails and have been playing with the table to try to get better suction so these pieces don't move. I have made changes that I think have helped, but it's hard to verify if one change made the difference or another so I thought I would ask for advice here.
First, while I understand that suction applied to a piece is a function of the vacuum power and the surface area of the piece, is there a correlation with the size of my spoilboard and the suction? The way I have it figured, I will get twice as much suction from a 2'x8' spoilboard as I would from a 4'x8' spoilboard because there is [roughly] half as much surface area for the air to pull through. Is this accurate? The guys upstairs are telling me that the table has the same suction whether I have a 1'x1' spoilboard or a 5'x12' spoilboard and I just can't see this being true.
Second, if I were to drill a 10mm hole through my spoilboard directly under where a narrow piece will be cut, will this create a localized increase of vacuum suction at that one spot and help hold the narrow piece in place? My thought is that the hole will provide less resistance than the MDF spoilboard and will create an increased point of suction directly beneath the narrow piece I wish to keep in place while also maintaining the same diffuse suction throughout the board and across the face of the piece. Or does it make no difference because the contact surface area of the narrow piece remains the same?
I would really like to have more control over my vacuum table so any help or advice anyone can provide will be greatly appreciated.
Thanks,
Parker