Vacuum table suggestions

[justin cornell]

Morning,

So I'm in search for a good vacuum table for our machine. We have a 4' x 8' table with two 4' x 4' down down draft tables supplied by the manufacturer. The tables that were supplied with the machine work ok, but soon as you put a full sheet of product on the tables and cover the entire area with vacuum the tables bow taking the laser out of focus. So what I'm hoping to get are a few suggestions on some vacuum tables that may work for us.

Thanks,

Jusitn

[Scott Shepherd]

Why do you need that much down pressure on them? There's no moving parts. Are you sheets really warped and you're trying to pull the warp out? Or are you just trying to pull the smoke out?

I can't image the need for that much vacuum on a laser. Can you explain more details about the situation?

[justin cornell]

Some of the items we've cut are 1/8 gasket material that's fairly rigid and comes from a roll so it usually has a slight warp to it. To top it off those gaskets are usually 40" in diameter. The table will help pull it flat with help from the fan but then it pulls the laser out of focus in some areas not cutting the material 100% causing use to go back and finish the cut with razor blade or hole punch on the holes.

For instance right now I'm finishing up a job of a few hundred 4" engraved cork coasters where if I had a large, true & flat table I could have done probably all or most of them in one pass instead of running them on a small 12 x 12 table I made just to get us by. The cork isn't bad but if I were just to lay them out on the table without pulling some vacuum the air from the laser nozzle would push them around a little. On something like this we could probably just use a gate valve and not allow so much air flow to the table and not effect the height to much.

[IMG][/IMG]

[Dan Hintz]

Seems like fixing the bowing of the original tables would be faster and easier than trying to retrofit something new. Shim where necessary, strengthen where necessary, and check height in multiple places as you go.

[justin cornell]

This is the overhead structure we built to hold the fan assembly supplied with the machine. Each 6" x 6" upright is pulling a vacuum through it and has a 4" hose that is attached to the downdraft tables when in use. Then there is the 4" x 4" piece in the middle that has the 4" hose attached for the carriage to remove the smoke/fume etc.

[Scott Shepherd]

Can you post a photo of the table with no work on it? Seems odd that you can pull enough vacuum with that setup to bow the table. Let's see the table and I'm sure someone can get it sorted out.

[justin cornell]

Seems like fixing the bowing of the original tables would be faster and easier than trying to retrofit something new. Shim where necessary, strengthen where necessary, and check height in multiple places as you go.

We've taken one of the tables apart to tinker with it and I wish it were as easy as shim it up. We made some reinforcements to their tables but it didn't help to much. We could build our own, but was hoping to find a suitable one just to purchase. I'm sure at our size table we may just have to make our own anyways, it seems they make smaller some of the cabinet style lasers, or ones machine specific.

[justin cornell]

Can you post a photo of the table with no work on it? Seems odd that you can pull enough vacuum with that setup to bow the table. Let's see the table and I'm sure someone can get it sorted out.

The pictures take awhile to upload for some reason. But when I say bow the table, I don't mean the wood table but the down draft table with honey comb. Its a 4' x 4' area so it can pull quite a bit and the construction isn't all that great.

[IMG][/IMG]

[Scott Shepherd]

So it's bowing the honeycomb, the pieces under the honeycomb, or the pieces that all that sits on? What's the honeycomb sitting on?

[Keith Winter]

Buy a new honeycomb, you might need to buy two and piece them together on something as large as this. As others have said replacing the honeycomb with a new more sturdy one will fix it more easily. Lots of threads on honeycomb makers if you search the forum.

Second suggestion what lens are you using? A longer lens won't fix the issue but might help with slight variances.

[Robert Schmiede]

Take the honey comb off and put more ribs (support) underneath it.

[Michael Kowalczyk]

put blast gates on your 4" lines so you can regulate the CFM intake . That's how I do it

[Scott Marquez]

I think your table needs more structural support. Bring it to the manufactures attention, he should be made aware of these problems. If they are in the business for the long term they will fix yours and make a design change, so future customers don't have the same problem.
scott