The water cools the workpiece in the process and prevents damage to the material. This method is being used in ever more applications, and in particular for materials that are hard to process, such as hard metals, cubic boron nitride (CBN) or diamond as well as all types of ceramics. It is also just as suitable for fiber-reinforced composites, titanium, cobalt and superalloys or semiconductor materials. Here are some current applications.
“The fundamental difference between our Laser MicroJet (LMJ) method and other laser techniques is the guiding of the laser beam down the inside of an inherently stable water jet as thin as a hair,” says Dr Amédée Zryd, director of applications, research, and development at Synova in Duillier/Nyon, Switzerland. The high-energy nanosecond laser pulses are coupled into the water jet, which is only a few dozens of micrometers wide, with the help of a sophisticated optical head. The water has exactly the same purpose as the optical fibers in communications cables whereby the laser light is internally totally reflected at the boundary of the water to the air. In contrast, the working range of a conventional laser system is very short because of the focusing that is done by lenses. This characteristic of LMJ lasers enables very deep cuts with true vertical, very smooth surfaces. The medium pressure water jet – up to 500 bar – prevents thermal damage and at the same time washes away any reaction residue from the workpiece.