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fabrica
Registered
Username: Daya
Post Number: 101
Registered: 10-2006
| | Posted on Monday, December 04, 2006 - 06:54 am: | 
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Now That I have made satisfactory progress with the table. I have to start thinking of a Vac or some other Hold down system.
Gerald, by reading varous threads on this subject I have understood that the Vacuum Hold down system is the best choice but is quite expensive. Do you have any DIY Vac system in mind which could bring down the cost. |
Gerald_D
Registered
Username: Gerald_d
Post Number: 778
Registered: 11-2005
| | Posted on Friday, January 26, 2007 - 01:25 am: |
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And then yesterday Fabrica asked here: "If I am to do a vac hold down what should the specs be for a vacuum pump. If I know the correct specs maybe I could find a used one from a Junk yard."
Fabrica, if electricity is cheap for you, and you have a lot of spare capacity at your factory, you can look for something around 15kW or 20 HP, made of cast iron, with 75mm [3"] pipe connections. Might sound huge, but this is what the really "industrial" guys use. (We use g-clamps...I can't come to grips with using 15kW of the earth's fuels to replace 3 clamps.....)
He replied: "Gerald, Same form here electricity in this country is damn expensive. So we will just forget it for the moment. It costs around US $ 0.08 per unit.
True I too will stick to G clamps and double sided tapes for the moment. " |
Gerald_D
Registered
Username: Gerald_d
Post Number: 781
Registered: 11-2005
| | Posted on Friday, January 26, 2007 - 01:48 am: |
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The size & price of buying and running a vacuum hold down is decided by the size of parts that you are cutting loose from the original boards...
Kitchen cupboard doors are big and you could manage with a cheap vacuum system. If you cut small jigsaw puzzle pieces then even the biggest vacuum pump in the world won't be big enough.
So, what a lot of people do, is to use small cheap "pumps", and when they have to cut out tiny pieces then they don't cut them loose. The small parts stay attached by bridges/tabs or skins which are broken right at the end.
The cheap "pumps" are vacuum motors or fully packaged industrial vacuum cleaners.
Good vacuum motors: (noisy if not mounted in an enclosure)
Grainger 2M433
Grainger 3HV25
Maybe better prices here? Another source.
Good vacuum cleaners: (high suction, low noise)
Fein Turbo III
For big tables like the MechMate it is typical to use 2 vacuum motors or cleaners on 2 halves of the table. |
Sheldon Dingwall
Registered
Username: Sheldon_dingwall
Post Number: 16
Registered: 08-2006
| | Posted on Monday, March 12, 2007 - 08:28 pm: |
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I'm gravitating toward an aluminum vacuum grid table top, but need to build a plenum to support the grid plate.
I'm thinking the plenum needs to be bolted to the table, then surfaced before mounting the grid plate.
Here's a link to a vacuum grid plate http://www.nemi.com/vacuum%20grid%20table.htm
1/2" or 3/4" alu plate might work for the plenum. Does anyone have experience using 6061 T6 plate for large areas vs cast alu jig plate?
(I've also posted this message on the Shopbot forum) |
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10. Base Table