Vacuum Table Advice

[Minium]

Thanks Peter,

I've attached a photo to show how I was doing it. Obviously all 6 locations had a box in them. Each aperture in the jig is 140mm x 80mm. The unused holes around the edge are blanked with masking tape.

Playing around this morning I'm almost convinced that it's a lack of suck from the vacuum cleaner. Sticking a box onto the end of the hose, via a holey rubber mat, it felt like I had enough retention. However, I guess that via the vacuum table that amount of suction is being divided 6 ways.

When you say that most vacuum pumps are 'positive displacement' what does that mean?