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Water Jet Machine Provides Cutting-edge Cuts

Aaron Monteleone (left) and Tom Moss stand next to MFD's new water jet. (Photo by Lori Ann White.)

The SLAC Mechanical Fabrication Department has a new way to cut custom machine parts. Called a water jet, the machine uses a millimeter-thick jet of water traveling at twice the speed of sound to precisely cut custom parts out of everything from stone to ceramics to plastics to metals. It is not only capable of cutting a wider variety of materials than prior technologies, but can do so more quickly and more economically, according to MFD Production Planner Tom Moss.

"We installed this machine as part of our ongoing effort to increase efficiency and reduce costs to our customers," Moss said. The water jet's contributions to MFD's bottom line are obvious when the abrasive-laced jet is compared to the plasma and flame cutters it replaces. All three tools can be used to fashion a rough version of a custom part from a piece of material called a part blank. "We have to start with part blanks of the appropriate size," Moss explained, but using the plasma or flame cutting process for the initial shaping "requires a larger blank so you can machine away the heat-affected zone and slag," metal that has chemically combined with cutting gasses.

The water jet puts out a millimeter-thick "blade" of water at 60,000 pounds per square inch. (Photo by Lori Ann White.)

By comparison, the water jet allows a closer shave.

"We can now cut some parts right to the finished dimensions, depending on the tolerances required," Moss said. Regardless, the MFD machinists will be able to start with blanks that are much closer to the finished size and that require less finishing work, saving both material and time. In addition, the water used for the jet is simple tap water that is completely recycled; the only water loss results from evaporation.

The cutting power of the jet comes in part from garnet grit added as an abrasive, but the real force behind the jet lies in the 60,000 pounds per square inch at which the water exits the nozzle—more than three times the pressure at the deepest point in the ocean.

In addition to handling a wider variety of materials, the water jet can accommodate large parts. According to Moss, it can cut material up to 13 feet long by 6.5 feet wide by 7 inches thick. Setup time is also minimal—another cost savings.

"It's an amazing machine," said Aaron Monteleone, who maintains the machines in MFD and who helped get the new jet up and running. "I don't do much machining, and it's so simple I can use it."

The water jet may be easy to operate, but it's capable of cutting very elaborate shapes.

"The shapes you can cut with this machine are only limited by your imagination," he said. "We definitely want to encourage our customers to think about how they can take advantage of MFD's new capabilities and the cost savings that it offers."

—by Lori Ann White
SLAC Today, January 4, 2011