Waterjetting Thick Steel

[Miguel Gonzalez]

We're currently attempting to waterjet cut thick steel plate (6in. thick) and are having some problems.

The machine has to run at such a low feedrate to cut the material, the jet has actually punched through the bottom of the table and we had to empty out the table to plug the hole.

We've tried putting a thick sheet of steel at the bottom to help reduce this but I'm looking for any other solutions others have come up for this.

Is there any system around that counters the vertical force of the waterjet with a horizontal water jet to intercept the jet after it comes out of the bottom of the workpiece and help disperse the kinetic energy before it makes contact with the bottom of the table?

Any other ideas?

[HuFlungDung]

I saw somebody had made a 'waterjet attachment' to use on a knee mill. I'm not endorsing the idea, but what they had was a layer of steel ball bearings at the bottom of the tank to deflect and disperse the jet. I'm not sure how thick the layer was, but it would be several ball diameters deep. How long those last, I don't know.

[Miguel Gonzalez]

That sounds like an interesting solution, I see how it might defelct the water, but wouldn't the jet push the bearings out of the way after a few seconds? How big were these ball bearings?

Also I'm thinking they would have to be made of Stainless Steel to keep the particles of rust getting into the water minimized having all that extra material in the tank? Trying to kind of get an idea of what the cost would be considering stainless steel has gone up in price alot in recent years. The price seems to have somewhat stabalized probably due to decrease in demand but it's still pretty expensive...

[HuFlungDung]

http://www.wardjet.com/Products.asp

I suspect that it works because there is very little surface on each ball that is exactly perpendicular to the jet. This means that you've got instant dispersion of the jet in a constantly changing angle of incidence of the path.

[xjdubber]

what about gravel in the tank?

[laka]

We have an Omax machine, it has 3 feet of water in the tank underneath the slats which disperses the water. How is your machine setup? or what brand is it?