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plasticman
23-12-2012, 11:22 AM
Can anyone tell me exactly what i need to create vacuum table on my hurco vmc1 using compressed air. Seen it used years ago but dont know the set up.h

GEOFFREY
23-12-2012, 12:07 PM
Hi, I had a Phoenix Magnum router (sold by Denford before they made their own cnc). The system as I understand it, was the compressor air blows over a venturi

tube which is connected to the vacuum matrix. this did work fine for engraving(not that I did much as I did not get to grips with the Procad software), but I am not sure how good it would have been after sucking through a sacrificial mdf board.

A disadvantage was that it needed my noisy compressor running all the time. I personally think you would be better off using a vac pump.

I have just made a vac table from pvc, which works quite well, but I had hoped to do away with my original ally table, sadly this was not possible as it did not

stay flat enough and I have had to reinstate the original table and bolt the vac table to it, reducing what was already a very limited Z travel. A friend

machined the plastic for me (too big for my fixed gantry router), but cannot machine another in ally on his machine.

Good luck if you do go for the compressor system, but I would go for a vac pump. Regards, G.

JAZZCNC
23-12-2012, 12:35 PM
You'll need a very high CFM compressor a Vacuum generator (venturi) and a tank,vac gauge,vac switch etc.
Have a look here http://www.joewoodworker.com/veneering/v2-assembleventuri.htm

But I agree with Geoff and go for the vac pump with a tank far far better and reliable.

Ger21
24-12-2012, 07:03 PM
You don't really want a tank with a continuously running pump, as it just adds more air that needs to be evacuated.

JAZZCNC
24-12-2012, 07:38 PM
You don't really want a tank with a continuously running pump, as it just adds more air that needs to be evacuated.

Merry Xmas Gerry. . . . . Your spoiled with that great big Monster you work on. . .Lol

Tank is handy for fast hold down and pump is switched on/off with Vac pressure switch. Also means don't need massive pump or compressor blasting away all time.

Ger21
25-12-2012, 05:13 PM
Merry Christmas to you as well. Yeah, 50 HP worth of pumps sure makes things easy. ;) But you'd be surprised how often you wish for even more.

I have a small electric pump that I'll be using on my next machine. I'll be using it with no tank, with dedicated pods or fixtures.

While a tank can help with the fast hold down, you'll get a bit more vacuum with no tank, as you won't get the drop that you get when the switch cycles the pump on and off. I have a veneer press that uses two venturi pumps, and the switch allows about a 4"Hg drop before the pump comes back on. A tank works best when you have a very good seal, so that the pump rarely needs to run. If you have any leakage, I'd skip the tank.

GEOFFREY
25-12-2012, 05:42 PM
Obviously sucking thru an mdf sacrificial sheet means some leakage all the time. I have divided my small bed (540x450) into two separate areas, each connected to a small (600W) 230 V vac pump plugged into sockets on the machine front. When ready to rout I simply flick the switches on then off again when finished.

This seemed to be the cheapest easiest option. G.