Experimental research of water-jet guided laser processing

The water-jet guided laser processing is based on the principle of full reflection. The laser beam is guided by the water-jet to do micromachining. A new coupling unit was manufactured to improve the coupling efficiency, not only can adjust accurately the relative position of laser beam and water-jet but also its special structures make the fluid field in the chamber symmetry and can form high speed, long working distance (78 mm), stable water-jet. The results showed that the attenuation of laser energy is relative to water-jet stability and coupling efficiency. The energy intensity distributed over the water-jet cross section nearly homogeneous and the energy nearly doesn't decrease in long working distance. Applying optimized machining parameters to cut Si and stainless steel, nearly no burrs, no cracks, no heat affected zone were formed. Different materials have different machining efficiency, i.e., stainless steel and Si were easy to machine. Bakelite was most easy to cut. Copper was hard to cut for its high reflectivity.