There are two main steps involved in the waterjet cutting process. The Electric Servo Pump generally pressurizes normal tap water at pressure levels above 50,000 psi; to produce the energy required for cutting. Water is then focused through a small precious stone orifice to form an intense cutting stream.
In the 1950s, forestry engineer Dr. Norman Franz experimented with an early form of water jet cutter to cut lumber. However, the technology didn't advance notably until the 1970s. Today the water jet is unparalleled in many aspects of cutting and has changed the way many products are manufactured. Many types of water jets exist today, including plain water jets, abrasive water jets, percussive water jets, cavitation jets and hybrid jets.
The key to cutting metal with water is to keep the spray coherent. Waterjets are able to cut because the spray is channeled through a very narrow jeweled nozzle at a very high pressure to keep the spray coherent. Unlike metal cutters, a waterjet never gets dull and it cannot overheat.
Low pressure waterjets were first used for mining gold in California in 1852. Steam and hot water jets were used in the early 1900s for cleaning. High pressure waterjets were used for mining in the 1960s, and about 10 years ago industry began using waterjets for cutting. Abrasive water jets (abrasivejets) were first used in industry in about 1980.
In the past, only one piece of metal could be cut at a time with a saw or other metal cutting mechanical process. It was time intensive and expensive. Computer-controlled waterjet and abrasivejet cutting are used today in industry to cut many soft and hard materials. The plain water-abrasive mixture leaves the nozzle at more than 900 mph. The latest machines can cut to within two thousandths of an inch, and have jet speeds around Mach 3.
Waterjets can cut:
A water jet can cut a "sandwich" of different materials up to four inches thick. This odorless, dust-free and relatively heat-free process can also cut something as thin as five thousandths of an inch. The tiny jet stream permits the first cut to also be the final finished surface. This single cutting process saves material costs and machining costs. For example, the engineer merely gives a gear drawing to the cutting shop via a diskette or e-mail and gets the finished gear back.