Re: Vaccuum table holes

Dave,

I've made vacuum hold down platforms that were like a waffle iron,
lots of open area between raised pads with little pieces of sand
paper on the pads for friction. If your parts can be marked on the
back side use little prick points like the end of a center punch
protruding up from the pads for more side-holding than sandpaper.
It's best to use locating pins to positively prevent the parts from
sliding sideways across the vacuum table if the part design permits.

Only one vacuum inlet is needed. The platform's outside perimeter is
sealed with a closed cell foam strip in a routed groove.

Use a reverse spiral, downcutting bit to eliminate the tendency of
the cutter to lift the part off the table.

For the ultimate, tie a vacuum actuated switch into your machine e-
stop circuit. If you get a sudden vacuum loss the machine shuts down.

With aluminum, most likely you won't want to cut it dry. Be careful
with coolant or mist if you're using a common Gast or similiar oil-
less pump, they can't tolerate any liquid being sucked in.

Doug

--- In CAD_CAM_EDM_DRO@y..., "turbulatordude" <davemucha@j...> wrote:
> 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