History of Waterjet and Abrasivejet

First uses of waterjets

Waterjets found their first industrial use in the early 1970's. At pressures between 40,000 and 60,000 psi, a jet stream of water approximately 0.005" (0.1 mm) in diameter could neatly cut many materials including food products and cardboard. Specialty machines were created to help cut line production products which previously were tricky to produce. Examples of these early applications include:

• Cardboard
• Disposable diaper lining material
• Insulating material
• Shapes from foam rubber
• Soft gasket material
• Carpet material for automotive applications
• Food products ranging from chocolate bars to fish fillets
• Fabric and sheet goods
• Components for shoes and leather products

Waterjets find new applications

Despite its cost and difficulty of maintenance, waterjets gained acceptance as a solution for cutting challenging materials. Waterjets were a viable alternative to knives and mechanical cutters which were far more costly and difficult to maintain. In addition to production line applications, waterjets soon were added to specialized machine shops working on a contract or job basis. These shops typically cut foam rubber, and other material into particular shapes for manufactured products, gaskets, custom signs, and other applications.

Birth of the Abrasivejet

While the ideal solution for troublesome soft materials, waterjets could not machine hard materials adequately. In the 1980's garnet abrasive was added to the water stream and the abrasivejet was born. This was accomplished through the development of a ceramic mixing tube that could not only create the water stream, but also mix in the garnet by means of aspiration. This new abrasive-laden stream could cut harder materials such as titanium, Iconel, glass, and ceramics.

Development of the Abrasivejet

Like their waterjet predecessors, abrasivejet machines were initially very costly and difficult to maintain. As a result, these systems were only used for specialty materials such as titanium wing panels on military aircraft or cutting difficult shapes from glass or ceramics. These original systems cut the materials in the open air, allowing the operator to actually see the stream and manually adjust the feed rate of the garnet according to the path of the nozzle. Accompanied by a cloud of garnet and material shavings, these early abrasivejet systems were limited to specialized job shops employing highly skilled workers.

In the early 1990s, waterjet pioneer Dr. John Olsen began to explore the concept of abrasivejet cutting as a practical alternative for traditional machine shops. His end goal was to develop a system that could eliminate the noise, dust and expertise demanded by abrasivejets at that time.

Such a system should also be simple enough to maintain without extensive training or expertise. Most importantly, the system would have a computer control system eliminating specialty training for operators and trial and error programming. If such a system could enable an unskilled operator to quickly produce an individual part to precise specifications on the first try, it could be used by thousands of small job shops and prototype shops for making one-of-a-kind and short-run parts.

Dr. Alex Slocum of the Massachusetts Institute of Technology teamed up with Dr. Olsen in order to help with the design of the mechanical system. Dr. Olsen used cutting test results and a theoretical cutting model originally proposed by researchers at the University of Rhode Island as a guide in developing the unique control system. The result was a PC-based control system combined with a precision XY cutting table on which parts could be cut underwater. This submerged technique drastically reduced noise and eliminated floating dust. Here was an abrasivejet system suitable for the short-run and limited-production machine shop market.