How Waterjet Cutting Works

The high-pressure waterjet is used as a tool to cut a wide range of materials.

The fine jet is very powerful, with cutting speeds between 100 and 500 mm/s for a variety of automotive carpets and from 300 to 500 mm/sec for headliners. In most of these cases, the materials do not have time to absorb the water and remain relatively dry.

The energy required for cutting materials is obtained by pressurising water to ultra-high pressures and forming an intense cutting stream by focusing this high-speed water through a small, precious-stone orifice. The stream moves at a velocity of up to 900 m/s, depending on how the water pressure is exerted.

The process is applicable to both water only and abrasive jets. For abrasive cutting applications, abrasive garnet is fed into the abrasive mixing chamber, which is part of the cutting head body, to produce a coherent and an extremely energetic abrasive jet stream.

Working pressure up to 4.200 bar

The inlet water is filtered and if necessary treated to reach the recommended quality before entering the Ingersoll-Rand high-pressure intensifier.

An electrically driven hydraulic pump (12 to 75 kW) is used to pressurise the process water with a double acting intensifier. The pressure peaks caused by the plunger reversing its direction at the end of each stroke are reduced by the attenuator connected to the high-pressure outlet line. The operating pressure lies between 3.000 and 4.000 bar, depending on the application.

The robot mounted cutting head contains both the air actuated on/off valve and the sapphire/diamond orifice. Its diameter is commonly 0,15 to 0,35 mm. A special mixing chamber with a focussing nozzle is needed when abrasive is added to the water.

Flexible cutting technology

Cutting routines for complicated 3D shapes that would be impossible to punch can easily be programmed with the robot.

The standoff distance between the nozzle and the part to be cut is about 25 to 50 mm. After it has cut through the workpiece, the jet turns into a spray and immediately loses its cutting power.