Re: Water Jet

>
> You are thinking heavy industrial. I have more in mind a small hobby unit.
> My idea is much like Mario in that I want to cut things like balsa upto
> 3/16" and maybe carbon laminates up to .020".

When I was still in the machine shop as a shop foreman, in our CNC dept.
we had a water jet that we used for mainly cutting 6" die steel and
nylatron. We would on occasion have a customer want some non-ferrous
cut, such as wood, but we found that the water spray left too much
residual water on the surface and would soak the wood, as well as what
seeped into the wood from cutting it.

>
> I have no clue what type of pressure or volume this would require. I wonder
> if good pressure washer with a 0 deg nozzle would be enough? I somewhere
> remember reading that they use a polymer additive in the water to reduce the
> divergence of the spray. Anyone know anything about this? Also, I am not
> quite sure if cutting balsa how to support it? I imagine that you need to
> have no obstructions under the material being cut in the path of the water
> stream?

Please don't quote me here, but I will take my best shot at it. If
memory serves me right we used a two-stage compressor for the water
pressure. The first stage built the pressure to 1000 psi. and the next
stage took it to I believe 3000 psi(and here I could be very off base)
at the cutting tip. Our tips were ceramic because of the sand used in
the water. Now that I have mentioned sand, it gets all over the place,
in the air, on the controllers, and the bed of the machine has to be
cleaned out every month. On our machine we had a 1/8" wide x 4" tall
grid work that all materials rested upon to be cut. These had to be
replaced as well as the jet would eventually cut away the steel bed and
not have too flat a surface anymore. The next area of concern came in
trying to keep the rails of the machine clean. The sand would get into
the Thompson bearing and just literally tear them apart, and we had
covers on all the rails, the sand will get everywhere. We also had a bit
of a problem in keeping all the wiring dry near the cutting tip for the
controls. This is some of the trials and tribulations that I encountered
with the waterjet. Overall for what we did with it, it was a great
workhorse for us and was running 20 hours a day. Another thing we had to
contend with was the noise. Our machine was very noisy for the other
shop members.

I cut balsa wood myself, and I have decided to go with a CO2 laser as it
will vaporize and not saturate the wood. Balsa has different densities
and if it is of the lighter density, will absorb most of the water
applied to it and warp. I did not want this.

Hope this helps,

Don Hughes

>
> More things to play with and no time.

Don Hughes