An Introduction to Abrasive Waterjet Cutting Technology

A water jet cutter, also known as a water jet or waterjet, is an industrial tool capable of cutting a wide variety of materials using a very high-pressure jet of water, or a mixture of water and an abrasive substance. The term abrasivejet refers specifically to the use of a mixture of water and abrasive to cut hard materials such as metal or granite, while the terms pure waterjet and water-only cutting refer to waterjet cutting without the use of added abrasives, often used for softer materials such as wood or rubber.

Waterjet cutting is often used during fabrication of machine parts. It is the preferred method when the materials being cut are sensitive to the high temperatures generated by other methods. Waterjet cutting is used in various industries, including mining and aerospace, for cutting, shaping, and reaming.

While cutting with water is possible for soft materials, the addition of an abrasive turned the waterjet into a modern machining tool for all materials. This began in 1935 when the idea of adding an abrasive to the water stream was developed by Elmo Smith for the liquid abrasive blasting. Smith's design was further refined by Leslie Tirrell of the Hydroblast Corporation in 1937, resulting in a nozzle design that created a mix of high-pressure water and abrasive for the purpose of wet blasting.

Working with Ingersoll-Rand Waterjet Systems, Michael Dixon implemented the first production practical means of cutting titanium sheets--an abrasive waterjet system very similar to those in widespread use today. By January, 1985, that system was being run 24 hours a day producing titanium parts for the B-1B largely at Rockwell's North American Aviation facility in Newark, Ohio. By August, 1985, Rockwell estimated the system had already resulted in $2 million in labor savings.

Dr. Mohamed Hashish, who led an engineering research team at Flow Industries working on abrasive waterjet cutting technology, was granted a patent for his design in 1987. Dr. Hashish, who also coined the new term Abrasive Waterjet AWJ, and his team continued to develop and improve the AWJ technology and its hardware for many applications which is now in over 50 industries worldwide. A most critical development was creating a durable mixing tube that could withstand the power of the high-pressure AWJ, and it was Boride Products (now Kennametal) development of their ROCTEC line of ceramic tungsten carbide composite tubes that significantly increased the operational life of the AWJ nozzle. Current work on AWJ nozzles is on micro abrasive waterjet so cutting with jets smaller than 0.015 inches (0.38 mm) in diameter can be commercialized.