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What is an abrasive waterjet?
An abrasive waterjet is a machining tool that uses high-pressure water mixed with abrasive to cut or drill materials of all types.
How does abrasive waterjet work?
High-pressure water (50,000-60,000 p.s.i.) passes through an orifice--typically made from a ruby or diamond--that ranges from 0.005 to 0.013 inches in diameter. The flow enters a mixing tube or nozzle that ranges in size from 0.015 through 0.05 inches in diameter. The stream of water causes a vacuum, which draws in finely crushed abrasive, which is typically garnet. As the water enters the mixing tube it blends with the garnet, exiting from the tube and making contact with the material. The stand-off (distance between the exit side of the mixing tube and the material) is important to determine. If it is too small, the mixing tube will clog. If it is too great, frosting (a haze on the material) will occur and specifications will become difficult to hold.
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waterjet-cut part. In fact, the
cost can be greatly reduced if
a lower-quality cut is allowable.
This depends, of course, on the
tolerances and edge quality that
are required. Please consult the
QUALITY WATERJET customer
service team to determine which
surface finish is best for your
application.
Does waterjet cutting produce
a taper on the material?
Yes. Taper is the difference
between the top profile of the
cut and the bottom profile.
Like surface finish, taper
also depends on the cutting
speed--the faster the cutting,
the larger the taper will be.
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What are the main advantages to using abrasive waterjet?
Abrasive waterjet causes very little stress to the material being cut, is a very flexible method of cutting complex parts and does not produce heat-affected zones as do alternative cutting methods such as laser, plasma and EDM.
How deep can abrasive waterjet cut?
An abrasive waterjet can cut any material, including titanium up to 10 inches thick. It can cut many other softer materials even thicker than this.
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What is the best surface finish waterjet cutting can achieve?
The best surface finish waterjet cutting can achieve is about 125 rms. While a premium-quality cut often achieves net-shaped parts that require no secondary machining, a lower-grade cut may be preferable. In some cases, a rougher surface finish is more desirable, especially with parts that do not require close tolerances such as those that are roughed out prior to final machining. Choosing the correct surface finish and taper is critical to determining the cost of a
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Generally, lower tolerances
permit faster movement of the
cutting heads and less
machining time. Higher
accuracy requires slower
cutting. When the waterjet
cuts though material quickly,
the cutting stream leaves a
V-shaped taper since it
cannot completely eliminate
the material. As cutting is
slowed to optimal speed, the
taper will be reduced until
both sides of the cut are
parallel or nearly parallel.
Generally, the taper on a
high-quality cut is 0.003" -
0.005" on each side. As
cutting is slowed further,
the stream widens at the
bottom, resulting in
reverse taper.
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