The water-jet guided laser processing is a new compound micro-machining process in which the laser beam passes
through the water-jet by full reflection onto the workpiece. In this paper, a new key component:the coupling unit was
designed and which would form a long, slim, high-pressure and stable water-jet. The couple unit made the fluid field in
the chamber symmetry; the coupling quality of the laser beam and the water-jet could be easily detected by CCD camera.
For its excellent surface quality, the nozzle with a
&fgr; 0.18mm hole got better machining effect than other nozzles.
Aiming at finding optimum machining parameters, experiments were carried out. The results showed the attenuation of
laser energy bore relation to water-jet stability. The energy intensity distributed over the water-jet cross section nearly
homogeneous and the laser energy nearly did not decrease in long working distance. When water-jet pressure was high,
efficient cooling of the workpiece prevented burrs, cracks and heat affected zone from forming. During cutting Si wafer
process, nearly no cracking was found; Adjusting reasonable laser parameters grooving 65Mn, the machining accuracy
would combine with the speed.