A traditional vacuum system incorporates a multi-zone approach whereby vacuum flow is directed through a tabletop grid surface and fixture board to hold-down a desired blank(s). This is a very efficient hold-down method due to the use of gasketing to seal off the vacuum right near the part edge being machined. The fixture board is usually a piece of 3/4-in.-thick cabinetmaker’s plywood for long life.
The fixture can be quickly and accurately machined using the actual part program. For production jobs, this hold-down system is most economical. For best results we recommend hold-down zones every 12 in. of table length for ease of setup and a milled top pattern that covers the entire aluminum table top on a 1-inch square basis. A 3- to 5-hp rotary vacuum pump with a continuous duty rating is required.