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Waterjet Machining
A water jet cutter is a tool capable of
slicing into metal or other materials using
a jet of water at high velocity and pressure.
It is often used during fabrication or manufacture
of parts for machinery and other devices.
It has found applications in a diverse number
of industries from mining to aerospace where
it is used for operations such as cutting,
shaping, carving, reaming.
The cutter is commonly connected to a high-pressure
water pump (a local water main does not
supply sufficient pressure) where the water
is then ejected out of the nozzle, cutting
through the material by bombarding it with
the stream of high-speed water. Additives
in the form of suspended grit or other abrasives,
such as sand and silicon carbide, can assist
in this process. Because the nature of the
cutting stream can be easily modified, water
jets can be used to cut materials as diverse
as fish sticks and titanium.
Beyond cost cutting, the waterjet process
is recognized as the most versatile and
fastest growing process in the world (per
Frost & Sullivan and the Market Intelligence
Research Corporation) . Waterjets are used
in high production applications across the
globe. They compliment other technologies
such as milling, laser, EDM, plasma and
routers. No noxious gases or liquids are
used in waterjet cutting, and waterjets
do not create hazardous materials or vapors.
No heat effected zones or mechanical stresses
are left on a waterjet cut surface. It is
truly a versatile, productive, cold cutting
process.
The most important benefit of the water
jet cutter is its ability to cut material
without interfering with the materials inherent
structure as there is no "heat affected
zone" or HAZ. This allows metals to
be cut without harming their intrinsic properties.
The waterjet has shown that it can do things
that other technologies simply cannot. From
cutting whisper thin details in stone, glass
and metals; to rapid hole drilling of titanium;
to cutting of food, to the killing of pathogens
in beverages and dips, the waterjet has
proven itself unique
History
of Waterjets
WaterJet Cutting is a technology that has
mainly evolved in the past two decades and
it has created ripples within the manufacturing
industry during this time, due to its versatility
and flexibility in usage. Many types of
water jets exist today, including plain
water jets, abrasive water jets, percussive
water jets, cavitation jets and hybrid jets.
Dr. Norman Franz is regarded as the father
of the waterjet. He was the first person
who studied the use of ultrahigh-pressure
(UHP) water as a cutting tool. The term
UHP is defined as more than 30,000 pounds
per square inch (psi). Dr. Franz, a forestry
engineer, wanted to find new ways to slice
thick trees into lumber. In the 1950's,
Franz first dropped heavy weights onto columns
of water, forcing that water through a tiny
orifice. He obtained short bursts of very
high pressures (often many times higher
than are currently in use), and was able
to cut wood and other materials. His later
studies involved more continuous streams
of water, but he found it difficult to obtain
high pressures continually. Also, component
life was measured in minutes, not weeks
or months as it is today.
Dr. Franz never made a production lumber
cutter. Ironically, today wood cutting is
a very minor application for UHP technology.
But Franz proved that a focused beam of
water at very high velocity had enormous
cutting power — a power that could
be utilized in applications beyond Dr. Franz's
wildest dreams.
Only in the 1970s did the usage of water
for cutting start advancing noticably. Today
the water jet is unparalelled in many aspects
of cutting and has changed the way products
are manufactured.
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