Re: Vacuum Table

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "cncnovice" <crcitser@...> wrote:

>
> Group,
> I have a 5ft x 5ft cnc router I built a couple of years ago. It has an
> aluminum table, and I now want to add as a accessory a vacuum hold down
> table of about 2ft(X) by 4 ft.(Y).
>
> Does anyone have any advice or plans that they would care to share?
>
> TIA,
> John Champlain
>

It is really simple to make such a table. the underlying table needs
to be flat, and if you check think and tinker, I think they carry a
foam that can be used for sealing the part.

A shop vac should be all you need for larger parts, as the total
surface area will potentially have tons of force.

Even at 10 inches of water (1/3 psi) per sq inch, a 3 sq inch area
would have one pound of force. That is about 50 pounds per sq foot,
or for a 4x8 sheet, about 1,500 pounds.

a stronger vacuum will offer more.

http://www.dwyer-inst.com/htdocs/pressure/ManometerIntroduction.cfm

A plastic tube hanging from the ceiling, filled with some food
coloring, and a tape measure would offer a crude, but simple way to
measure the vacuum pressure.

An auto store should have a vacuum gauge like this
Harbor Freight ITEM 93547-2VGA

Another tip is that a shop vac that is totally sealed may not deliver
as much vacuum as one that has a leak. the opening allows the pump to
move air, and work more in a sweet spot.

Dave