vaccum Plenum table chamber

[eloid]

looking to design vaccum Plenum table chamber
for 4x8 table, was thinking of integrating t slot (for safty )if I loose vacum or power with out worring about my material shift from it 0,0 orgin
What is design is most popular how many zone etc do you have?.

[eloid]

I found few ideas for a vaccum Plenum table top I like
see attached pictures. I plan on making a diy nemi pod system to be used
with my Plenum.. with independant zones,

[nomedia="http://www.youtube.com/watch?v=SfvQoQnQgmQ"]YouTube- The versatility of the PATENTED NEMI Slider Pod![/nomedia]
[nomedia="http://www.youtube.com/watch?v=X6hVL9bomh4&feature=related"]YouTube- Two Minute Setup![/nomedia]


I would like to use flow threw spoil brd as well for sheet good
if you have a Plenum table top pls post pictures of it

[CtrlZ]

I like this idea. I would be interested in seeing what diy design you come up with for the pods. Will they be similar to the nemi pods?

[Boltz]

The first question in planning a vacuum workholding system needs to be "is 3 phase power available." The amount of power required to run a flow through system is truly jaw-dropping.

If you're doing vacuum hold down on a 4 x 8, you'll need a 10-15 HP vacuum pump if you're working with MDF or thinner plywood. 20-25 HP would be best, but if you onion-skin and plan your cut order, you can probably get by with 10-15.

Obviously the first choice is 480v 3 phase, but if you have enough single phase you can run a converter.

Some of the Shopbot guys get by with a pair of Fein vacuum cleaners with a bleeder board, it works, but just barely.

I researched this for about a month and wound up buying a 10HP roots blower for my 4 x 4, hopefully tomorrow I'll have it up and running.

regards,
-Jim Hart

[eloid]

The first question in planning a vacuum workholding system needs to be "is 3 phase power available." The amount of power required to run a flow through system is truly jaw-dropping.

will be using ported system with plugs sys (prototype Plenum will be small scale at frist) yes 3 phase dyi rotar convert will be made ...
2x2
If you're doing vacuum hold down on a 4 x 8, you'll need a 10-15 HP vacuum pump if you're working with MDF or thinner plywood. 20-25 HP would be best, but if you onion-skin and plan your cut order, you can probably get by with 10-15. I agree ...read below..

yes I will onion skin my mfd sheet/ spoil brd..( plan on making blind pockets 1/2 diameter on one side ..more than half way into the mdf spoil brd ... on a 2 inch grid ) and use mask rubber gaskets seals mask off the require port location... will not be vaccum entire area ...just under the part as require in key location.

Obviously the first choice is 480v 3 phase, but if you have enough single phase you can run a converter.
yes see above

Some of the Shopbot guys get by with a pair of Fein vacuum cleaners with a bleeder board, it works, but just barely.

[nomedia="http://www.youtube.com/watch?v=NBN5sK0CyXg&feature=related"]YouTube- Building a Vacuum Hold down System - Part 1 of 2[/nomedia]

[nomedia="http://www.youtube.com/watch?v=l5h7m7vJJfs&feature=related"]YouTube- Building a Vacuum Hold down System - Part 2 of 2 (revised)[/nomedia]
this guy has a simular concept however

1. torsion box chamber to large for the "vaccum" chamber req.. idea is to have small Plenum chamber takes less time to pull a vaccum and small race ways from hole to hole( 1/4 raceway from plud to plug in the Plenum
2. He losing to much vaccum from 2 sheets of mfd on his donner brd and Plenum top
3. it not a port / plug table top so you cant mask out region of required vaccum
4. Plenum is mfd need to be hdpe something that dont leak .
5. you can make pods for small jobs or mask out regions and open the required plugs and seal area with rubber seal on Plenum and still use a onion skin spoil brd out of mdf.


I researched this for about a month and wound up buying a 10HP roots blower for my 4 x 4, hopefully tomorrow I'll have it up and running.

[ger21]

Some of the Shopbot guys get by with a pair of Fein vacuum cleaners with a bleeder board, it works, but just barely.

The current trend seems to be running up to 4 of these.
http://www.centralvacuummotor.com/shopbot.htm

http://www.talkshopbot.com/forum/sho...1&postcount=94

This one is really sweet.

http://www.talkshopbot.com/forum/showthread.php?t=440

[Boltz]

Yeah, I started adding up the cost of those blowers and looking at their expected lifespan and decided I needed to think differently.

For a grand I was able to buy a Gardner Denver Cycloblower (which is somewhere in between a roots blower and a helical screw) with 10HP motor, motor starter, filter, muffler, and relief valve, mounted on a welded steel base. It'll pull 200CFM at 16" with this motor, and the spec sheet rates it for up to a 15HP motor, which would move 338 cfm, and it's built to run 24/7 for multiple years before needing rebuilding.

There are 4 more similar units on ebay. The "giant sucking sound" has never been cheaper!

The recession has resulted in a lot of top quality industrial equipment selling at fire sale prices. There are about a half dozen 15HP Reitschle vane style pumps listed on ebay for $1999 or best offer. One is about 5 years old, and looks like it's hardly been used.

-Jim Hart

[eloid]

anyone know where to source the black vaccum foam that would be simlaur to the frist post that work in the techno style of Plenum,

Also looking for afordable dyi also solution, if you know of products that work well.

[ger21]

www.allstaradhesives.com

[Boltz]

I have more time than money, so I searched a bit more and was able to find the 1/4" closed cell neoprene (I can't see that well, but it looks like that's what Techno is using) without adhesive from Mcmaster. If you're on a shoestring budget you can get a big sheet of it and slice it into strips with a good sharp blade and a straightedge.

Keep us updated on what you're using for a vacuum source!

-Jim Hart

[Dave's_Not_Here]

Worn out Shop Vac, 2x4's, 9ply plywood and a grid system of holes, surfaced top... And I can cut sheet goods without issue. The picture of my 4th axis captures the vacuum table....

The vacuum table is held steady by cam-clamps. There are (4) 2x4 cross members inside the table. The top is only screwed down and sealed on the seams with silicone. This way, if I need to replace the top before I get my table modified for the Fuji Ring Compressor, I don't have to destroy the vacuum table in the process. I didn't even worry about jointing the edges of the 2x4's, as the silicone and surfacing the table would correct the abnormalities.

I have tried to dislodge the panels and I cannot make them budge. Putting channels into the table for making smaller grids using gasket material, would make it more universal... but for my projects, it was not necessary.

I have a 10HP Fuji Blower (New for $800) and a 10HP VFD (New for $1K) to take the place of the shop vac.

I am making my own table extension for my Techno Isel table, as $3K for a 6" x 50" factory extension kit is waaaaaay over the top....

I cut dozens of panels below, on my $50 vacuum table... and charged $225 for each 4'x8' panel I processed... pretty good ROI

Dave

[ger21]

It's not really a $50 vacuum table if you spent $1800 for the pump, is it?