WATERJET FAQ

 bridge WATERJET FAQ

How much do I have to spend on a waterjet cutting system? 

Caldwell Machinery offers new waterjet cutting machines starting with $50K only. A middle line of product typically goes from $120,000. We can certainly meet your customization needs. Please contact us for a free and no obligation quotation.

What tolerances can we expect from waterjet cutting?

80% of world’s abrasive waterjets have kerfs around ±0.003 inch or looser. Others may have kerfs around ±0.0005inch to ±0.001. With Waterjet technology, the tolerances will be sharper.

Should I cut underwater?
Underwater waterjet cutting reduces the noise to under 75dB and eliminates material frosting within 1/16″ from the jet. T he downside of this process is you need water level control on your catcher in order to see the underwater cutting process. Without the control, you need to work underwater and handle the cutting process.

How thick can it cut?
Operators cut up to 8-inch steel and titanium in production. There have been cases where 12″ and even 15″ thick materials have been cut. However, majority of cutting from operators ranges from 1/4″ to 2″.

What kind of abrasive are you using?
Garnet is by far the most commonly used abrasive material. It is abundant, cheap, enhances cutting speed, increases tube life and reduces health hazards. Other abrasives include olivine sand, aluminum oxide, and some man-made materials

At what pressure do you cut?
Waterjets cuts at 90,000psi. It is also the maximum intensifier pump pressure. Although higher pressures can result in higher maintenance cost on intensifier pumps especially on the seals, the result is higher cutting speed and efficiency.

What taper can I expect?
With a Waterjet system, you will experience virtually no taper. In the case of conventional waterjet cutting, the taper you get is a function of the cut speed. However, the worst taper you will get will be equal to the maximum kerf width at the top (example: 0.035″) and 0.000″. at the bottom. As you slow down the taper will be reduced until you get parallel sides. Most tapers you see on precise cuts are 0.002″ to 0.004″ on a side.

How much water will you use when cutting at 55,000 psi?
Each 0.010″ orifice uses 0.5 gpm.
Each 0.013″ orifice uses 0.82 gpm
Each 0.016″ orifice uses 1.24 gpm

When is maintenance required at the pump?
You need to replace the high pressure seal after 400 to 1200 hours of usage on a 55,000 psi intensifier and replace the seal after 200 to 600 hours of usage on a regular pump.

What is the minimum water level depths?
In most waterjet systems 36 inches of water in the catchers dissipates the energy of the jet.

How long does the material support last?
You can expect hundreds of hours of production time from the support grating before the need to replacing it. We recommend that, as long as you don’t cut just one pattern over the same section for thousands of parts, slats and grates can be shifted, swapped, and flipped just as with plasma and laser cutting. Thus, this will extend the life of the grating supports.

How long does the mixing tube last?
The highest quality ceramic carbide mixing tubes last 30% longer than other mixing tubes. A tube such as this can deliver 150 hours of cutting time for 0.020″ in diameter. Many users keep the mixing tubes longer and use them to cut parts which require looser tolerances.

How much abrasive is used?
For the most efficient cutting, cutting heads on a 55,000 psi intensifier use:
0.010/0.030     0.9 lb/min
0.014/0.040     1.4 lb/min
0.018/0.050     2.5 lb/min

What about programing A&V Waterjet machine?
Our systems are relatively easy to program as compare to any other waterjet cutting system. Our professional PC based waterjet software is capable of reading any 2D DXF files. Programming for abrasive waterjets is quick and easy. An operator with little experience should be able to learn how to program and operate the machine within one week.

What weight is required to press and hold down the workpiece?

Since the force exerted on the workpiece is very small (under 1 lb. for precision cuts and under 5 lbs. for average cuts), the need for very large and stiff fixtures is eliminated. Many customers use simple weights to hold the parts in place.

What are the operating costs of a waterjet?
Hourly machine cost ranges from $19 per hour for the small head (0.010/0.030) and up to $35 per hour for the large head (0.016/0.040). It does not include labor, lease, and depreciation.

What is the cost of the abrasive?
Abrasive will cost between $0.16 per pound to $0.40 per pound delivered, depending on the type and quantity you purchase.

How loud is it?
Noise from the waterjet is dependent upon the distance the supersonic jet is exposed to the open air. If you are cutting underwater, the noise level will be under 75 dB. If you are cutting above water, and especially if there is a large distance between the mixing tube and the work piece, the noise will be much higher, up to 95 dB. In these cases, most customers enclose the entire work area.

How do we dispose of water/garnet?
Neither water nor garnet are toxic or hazardous in any way. Water, when properly filtered for turbidity, can be flush down to the drainage systems. The garnet waste can usually be dumped in a standard landfill.

Is this pure water?
It is clean water. Most of our customers use softened tap water. Intensifier pumps should be supplied with filter cartridges that clean the water down to 0.5 micron. De-ionized or reverse osmosis systems are generally not recommended. These types of systems can make the water too clean, which makes the water aggressive and harmful to the pump.

Do you recycle the water?
Recycling systems are available. However, because waterjet systems use a small amount of water it is not economically viable for most users.

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