Ultra-High Speed Pulsed Water Jet - A Potential Tool for Stone Materials Machining

Today water jet machines are more and more used for rock materials cutting in China and its advantages are well known. Due to the ultra-high pressure, which is in the range of 200-300 MPa for a typical water jet machine, the ultra-high pressure water system is not reliable at present. The average life of high pressure cylinder is only 500 hours. Obviously it is too short for commercial use. On the other hand, the abrasives are usually added in order to cut rock materials. It makes water jet machine a little bit complicated to operate in use and shortens the life of nozzle assembly. Moreover it actually results in environmental problems. All of these issues limit the expanding applications of water jet machining. The ultra-high speed pulsed water jet has been known to have significant advantages over continuous water jet in cleaning and cutting of various types of materials. In this paper, a new concept of water jet machine using water slugs of ultra-high speed (#~2000 m/sec) is proposed. Some critical issues about producing high-speed water jet are discussed and suggestions are also given in the paper.