Choosing and Using
Waterjet Cutting
The tech has been around for
a while, but improvements are
making it all the more efcient.
By RAY CHALMERS / Contributing Editor
Since its introduction in the mid-1970s, waterjet cutting has
grown in popularity based largely on its versatility. Chip
Burnham, vice president at Flow ( fowwaterjet.com ) says
the cold-cutting process is in use at virtually all automotive
OEMs and tiers for cutting resins and foams for headliners
and bumpers, and also superhard materials, including
nickel-based alloys. There are 2D cutting heads for cutting
fat stock in stacks and fve-axis 3D heads for profling and
contouring, as well as multi-axis robotic systems.
"Pure" waterjet, a stream of water pressurized up to 94,000
psi and formed into a jet the diameter of a human hair, is the
faster cutting process for softer materials. Adding garnet to
the stream for abrasive waterjet, a process invented at Flow,
slows the process somewhat, but increases accuracy, (as the
stream thins and cuts become more precise), all with no
heat-afected zone or work-hardening on metal parts.
Because increasing the fuid pressure makes waterjet
cutting faster, the system's pump is important. The linear
intensifer pump is the original, and most common, tech-
nology used in waterjet cutting, according to Flow, using the
"intensifcation principle" to pressurize water. Hydraulic oil
is pressurized and pushes against a biscuit with a face area
20 times greater than the face of the high-pressure plunger
that pushes against the water. This intensifes the pressure
20 times. In other words, 3,000 psi of oil pressure generates
60,000 psi of water pressure due to the 20:1 ratio of biscuit
area to plunger area.
A Dynamic XD cutting head on a Flow
Mach 4 machine cuts aluminum.
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