How does a Water Jet Cutter Work

The amazing tech that enables water to accurately cut both soft and hard materials.

Waterjet cutting can be used to slice through most materials and is a process that does not give off hazardous vapours or waste.

Intensifier or direct drive pumps get the water to the high pressure needed for cutting. The more powerful intensifier pump uses hydraulic oil pressurised at 211 kilograms per square centimetre (3,000 pounds per square inch) to drive a piston biscuit/plunger. This pushes a flow of filtered water that is intensified by 20 times to 4,218 kilograms per square centimetre (60,000 pounds per square inch).

Pure waterjets are used to cut card, nappies and soft materials. The velocity of the water from the jet, rather than the water pressure itself, erodes the microscopic grains of the material using this technique.

Abrasive waterjets, on the other hand, incorporate a rough substance like sand that is accelerated by the water to erode the material, which can include metal, stone or ceramics.

The simplest variety of waterjet machine tools are stationary and cut the material fed into them much like a bandsaw. The more complex programmable five-axis machines, meanwhile, can cut composite materials in three dimensions.

Waterjet cutter parts

Water inlet – Water is pumped in at a pressure around 211kg/sq cm (3,000psi).

Orifice – Consists of a sapphire, ruby or diamond with a 0.1-2.5mm (0.004-0.1in)-diameter hole in it, which drastically increases the pressure of the water.

Abrasive inlet – Hard sand or garnet is sent at high speed to the mixing chamber. 80 mesh-sized abrasive is used for general purposes and 120 mesh for smoother surfaces.

Mixing chamber – This 76mm (3in)-long tube acts like a rifle barrel to accelerate the abrasive particles. It can have a diameter of between 0.5-1.5mm (0.02-0.06in) depending on the material being cut.

Abrasive nozzle – Water jets out at a speed of approximately Mach 3; that’s 3,676km/h (2,284mph)!