In 1993, scientists at the Institute of Applied Optics of the Swiss Federal Institute of Technology Lausanne, Switzerland, demonstrated the feasibility of a hybrid laser system using a water jet as light guide. The laser beam was focused into a nozzle while passing through a pressurized water chamber. Once coupled to the water jet, the laser light is guided inside like in any optical waveguide. The light guiding jet hits the sample, which is machined by the laser pulses contained within. The stable water jet thus works as liquid waveguide delivering the laser light to the work piece. The jet also efficiently expels the melt from the cut, and cools the cut, thus avoiding thermal damage to the sample.
10 years after the demonstration of the principle, engineers at Synova present a summary of the development paths that this technology has undertaken. From the very first trials till today’s efficient industrial machines, the Laser Microjet®, as its inventors called it, underwent many refinements, concerning mainly the coupling device, stability of the water jet, and the laser sources employed. The evolution of these three points is reported briefly, and illustrated by some application examples for the different laser types. Research continues aimed at better understanding of the cutting phenomenon, further miniaturization of the water jet, and a wider choice of laser sources.