The technology behind waterjet cutting

Written by Bruce Hughes on . Posted in Gadgets

You may wonder how water can actually cut through steel, but waterjet cutting has been used in machine shops for many years now in order to cut metal parts. The technology was first used for mining gold in California, but those were low-pressure waterjets. Today’s process uses a very high-pressure stream of water, which can cut through metal if it flows fast enough. However, the technology behind this process is not that simple, as you can imagine. In fact, there are certain requirements that need to be met in order for the cutting to work and one of the key prerequisites is keeping a coherent spray. Waterjet cutting machines are able to achieve the high-pressure needed for the flow to cut through metal by channeling the spray through a nozzle that is very, very narrow. Waterjet machines differ from metal cutters through the fact that they cannot overheat and don’t get dull.

When the process of Wasserstrahlschneiden was first used for metal cutting, the machines could only cut through one piece of metal at a time. Because of that, the process was neither time effective nor affordable. However, with the advancements in technology, waterjet cutting machines today are computer controlled and they can cut through many materials, whether soft or hard. The materials that waterjet machines can cut range from metal, stainless steel, marble and granite to stone, plastic and wood and such a machine can cut many different materials piled together, up to a thickness of four inches. The technology behind these machines also allows them to cut through very thin materials, such as an item that is as thin as five thousandths of an inch. There are many benefits to the waterjet cutting technology, such as the process being dust free, heat free and also odorless, but also the fact that it delivers a finished surface from the first cut. This particular feature saves both machining and material costs. In order to reduce noise and water splashes, the actual cutting takes place under water and engineers use faster feed rates in order to avoid cutting all the way through.

 

As mentioned above, the waterjet cutting process only works because the flow of water is coherent and has very high-pressure, while being channeled through a narrow nozzle. Well, the pressure of the water starts from 20, 000 pounds per square inch, or PSI, and can go as high as 55, 000. The diameter of the nozzle or orifice is somewhere between 0.010″and 0.050″. Some engineers add a soluble polymeric chemical into the water, in order to modify its chemistry and tie the individual water molecules together. As a result, the water gets a more structured arrangement and thus forms a coherent jet, increasing its potential for cutting. The bottom line is that waterjet cutting technology revolutionized many fields and industries in which cutting metal parts was necessary, by reducing costs and operational times and providing a finished surface right away.