The first technical applications of waterjet technology date back more than 100 years. Around 1870, waterjets were first used to extract gold. Once suitable pumps had been developed, it was possible to increase water pressure far enough to be able to cut non-metallic materials.
Then, at the start of the eighties, solid particles were added, the most recent innovation in the evolution of waterjet technology. Today it's possible to cut practically any material with pure waterjet respectively abrasive waterjet.
Waterjet technology has a variety of advantages in terms of the specific process:
Essentially, we can distinguish between two different processes:
Cutting with the pure waterjet and abrasive waterjet cutting.
While pure waterjet cutting relies on the static pressure of the compact waterjet and the erosive effect of the droplets in order to cut the material, in abrasive waterjet applications there are the solid particles incorporated in the jet which cause micro-cutting action on the material – in this case the waterjet serves merely to accelerate the solid particles.
Essentially, both types of jet can be used for cutting materials as well as cleaning and removing, while cutting it is possible to obtain a variety of qualities of the cut edge depending on various parameters. Various quality zones are created on the cutting surface whose size will depend on the selection of cutting parameters.
As opposed to when used in cleaning applications, where the main objective is to achieve large surface, constant removal of material, waterjet cutting works on the principle of coherent jets. The jet diameter ranges from 0.1 mm to 0.5 mm (0.004" to 0.016"). In order to achieve the necessary energy density, the operating pressure is up to 420 MPa (60,000 psi), which corresponds to the pressure at the base of about 42 km (25 miles) water column.
Depending on the material pure waterjet is able to cut up a thickness of 300 mm (12").
The abrasive waterjet
In connection with many technical materials the energy density of pure waterjet is not sufficient to cut. This is why solid particles have to be added to the waterjet. In such cases far greater cutting performance are achievable.
Typical waterjet cutting applications are:
The so-called abrasives are usually a sharp-edged mineral material such as garnet or olivine at a grain size of approx. 0.1 mm to 0.3 mm (0.004" to 0.012"). Depending on the specific cutting application, the amount of abrasives required varies between 100 and 500 g/min (0.22 and 1.10 lb/min).
The pressure used in abrasive waterjet cutting is the same as in pure waterjet cutting, i.e. up to 420 MPa (60,000 psi). The jet diameter is between 0.3 mm and 1.2 mm (0.024" and 0.047").
As a limit for thickness while cutting with abrasive waterjet we look at approx. 250 mm (10").
Typical applications are: