How Does Waterjet Cutting Work?

Waterjet cutting machines are a very popular way to cut two-dimensional parts from sheet metal and flat plate. It can be used to cut heavy plate such as might be used by equipment manufacturers, steel service centers, machine shops, and fabricators. This form of cutting offers incredibly straight cuts and produces no heat.   Water Jet Cutting is a Heat-Free Process   When you think of metal cutting, it’s probably in terms of laser, oxy-fuel, and plasma cutters. All of these have one thing in common, they all produce heat as a by-product of the cutting process. Waterjet cutting is more of a sawing process similar to a band saw in which a thin strip of metal with cutting teeth is pulled through the material to be cut. Instead of a blade, thin streams of water containing and abrasive material like garnets under high-pressure cut through things like sheet metal.   While garnets are the most common abrasive material used, however, you may find other materials being used. Garnet is the same abrasive used to make many types of sandpaper because of its relative hardness. Each piece of abrasive material wears away a tiny piece of the material being cut, resulting in a perfectly straight cut with little to no heat being produced.   It’s All About Speed   If you were to fill a bucket with water containing garnet and pour it directly onto a piece of sheet metal, nothing much would happen. The reason for this is the lack of speed at which the abrasive mix hits its target. In order for this mixture to cut, it must be moving at a very high rate of speed. To do this the mixture must be highly pressurized. Depending on the system being used and what is being cut, these pressures typically range from 50,000 to 90,000 psi.   Once pressurized, the mixture is then forced through a small orifice that has been cut into diamond or sapphire (two of the hardest natural materials known to man). The orifice is not much bigger than 0.005 to 0015″ in diameter. This tiny orifice supercharges the speed of the abrasive mixture to a point at which it is traveling at more than the speed of sound. Despite the pressure and speed, water consumption is approximately 1/2 a gallon per minute.   Cutting Using an Abrasive   The abrasive mixture and speed at which it is traveling by the time it exits the nozzle can wear through almost any material. This includes sheet metal, aluminum, stainless steel, ceramic tile, granite, glass, laminates, even armor plating. One of the few things waterjet cutting cannot be used for is cutting tempered glass as it is too brittle.   Any heat that is produced by the abrasives wearing at the material is rapidly cooled by the stream of water being used to carry the abrasives. The high speed at which the particles leave the nozzle help keep them flowing in a straight line as they cut through the material, making it possible to make very straight cuts.   If you would like to know more about waterjet cutting or need this type of service, contact Additive Manufacturing, LLC at (887) 238-7907 or fill out our information request form online today!