What is water cutting?

A. Definition

The so-called water cutting is that the ordinary filtered water pressurized by the booster unit to have the pressure of over 380Mpa, then the water is jetted out at a high speed about 800～1000m/s(about three times the speed of sound) from the gem nozzle, a special energy switch. This jet can cut kinds of soft materials, such as food, cardboard, diapers, food and all kinds of foam materials. For the design is complex, material is thick, hard to cut, fragile and kinds of material which couldn’t be cut in traditional cutting, water cutting is the most appropriate cutting tool to use. But for some hard materials like metal, glass, stone, ceramics etc., we can use the special cutting head with abrasives (garnet) into the water to improve the cutting capacity greatly.

B. History

In nature, water power incorporates in water erosion, we have word dripping wear away the stone, there are tens of millions years that water erosion on the earth surface. And effective use of the water beam, it has begun in the quarrying industry one hundred years ago.

In twenty century thirty years, the United States and the Soviet Union engineers have used high-speed jet technology in mining rock, stone and coal. HP water cutting, it was in the continuous development since then. The water beam as a tool used for manufacturing processes, the first is in the aircraft manufacturing and aerospace industries.

From the development history, UHP water jet technology is initially proposed by the Soviets and complete by Americans. The first patent of UHP water jet is declared by the U.S. Ingersoll-rand Mccartwey manufacturing company employee. Since 1971, the company developed the equipment with this technology successfully cutting a variety of materials.

C. Applications

In order to produce enough energy to cut, the water need to be pressurized up to over 300MPa, then the water was jetted out at a speed of about 800-900m/s from the energy converter (gem nozzle) of dia. 0.2mm～0.26mm. That is, the production of cutting energy is that after the high pressure water pass from the energy converter, the pressure energy converted to kinetic energy. This energy is enough to cut off the soft material, like plastic, wood, rubber and foam products, this is the “pure water cutting”.

In order to cut hard or composite materials, it needs to add the abrasive into the water beam (garnet, 60~80 mesh). The abrasive cutting can cut almost all the materials under 100mm(but the pressure is high and cross section is poor).

D. Accuracy

The cutting accuracy of workpiece is up to ± 0.1mm.

The accuracy of the workpiece depends on the machine accuracy, cutting size and thickness.

E. Cutting section quality

According to the cutting material, thickness and cutting pressure, cutting speed different, the cutting section quality are different, see the chart shown below.

The general rule is: material harder, pressure lower, speed faster, the cutting surface quality worse.