Waterjet Cutting. Just call it rapid erosion. Waterjet cutting relies on a high-pressure water pump to push water through a nozzle where the water is mixed with an abrasive, such as garnet or aluminum oxide. The combination of the jet of high-speed water and abrasives erodes the material at which the nozzle is aimed.

Waterjet cutting makes sense for those shops that want to cut a variety of substances, not just metals. Waterjets can be used to cut material as diverse as glass and rubber.
When it comes to metals, waterjet cutting is popular because it produces a cut with no heat-affected zone. The material is not distorted around the cut, so a very good surface finish is the end result.

A waterjet cutting machine can cut thin sheet metal easily and up to 12 in. thick, if necessary. Obviously, as the waterjet cuts thicker material, tolerances drop while cutting times increase.
The ability to make precise cuts is another attractive benefit of waterjet cutting. Fabricators can cut small parts with a tolerance ± 0.001 in. or better and large parts with a tolerance of ±0.003 in. to ±0.005 in.

Advancements such as servo driven pumps, multiple cutting heads, and automatically tilting heads, have helped to make waterjet cutting a much more competitive metal cutting technology.