Re: [CAD_CAM_EDM_DRO] Re: Using Vacuum to hold down sheet metal.

You don't need to open them up just chamfer them , it's all about
surface area .

cncnovice wrote:

>
> John,
> I built a vacuum box from MDF to hold balsa sheets for my router. I
> used 1/8 inch holes on 1 inch centers. Vacuum source is a shop vac.
> The vacuum also holds the box to the alum table of the router (bottom
> of the box is open). I cover unneeded holes with paper to maximize
> vacuum against the balsa. For small parts, I have to use tape to
> keep them from slipping out of place as the final cut is made, or
> leave tabs which I later cut with a knife to separate the parts from
> the sheet.
>
> I am considering opening the holes to 5/32 or 3/16 to increase
> holding force for the small parts, and I may decrease hole centering
> to 1/2 inch.
>
> If you use other than a shop vac as a vacuum source, be sure you have
> a good filter between the box and the pump.
>
> Regards,
> John Champlain
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com
> <mailto:CAD_CAM_EDM_DRO%40yahoogroups.com>, John Dammeyer <johnd@...>
> wrote:
> >
> > I have some 0.050" thick sheet metal in which I want to drill/mill a
> > number of holes along with a rectangular cut-out. The G-Code is
> done.
> > Things look like they will end up in the right place.
> >
> > I was thinking of building a vacuum assembly to hold the metal down
> > while milling. I've put in mechanical stops to prevent shifting
> but I
> > was thinking if I built a box and connected the shop vac that I'd be
> > able to use lots of little 1/8" holes through the MDF frame to suck
> down
> > the metal.
> >
> > A bit of math tells me that the 7 square inches of a 3" diameter
> vacuum
> > hose translates into about 575 holes 0.125" in diameter.
> >
> > But do I really need that many. I plan on only putting holes under
> the
> > metal where the mill does not do any cutting so no leaks.
> >
> > Would this work? Is it better to use a vane type vacuum pump
> instead?
> > The milling cycle for all the holes is about 00:05:45 so that would
> mean
> > the shop vac would be straining for a fairly long time perhaps
> > overheating.
> >
> > Suggestions?
> >
> > Thanks,
> >
> > John
> >
>
>

--
Ron Kline

American Precision Ceramics .. (Industrial ceramics)
Central Ky.