Process for machining workpieces by means of laser beams

: Beyer, E.; Herziger, G.; Loosen, P.; Poprawe, R.

Abstract
Process for the processing of workpieces by means of laser radiation, which generates a non-shielding, energy-coupling, laser-beam induced plasma at the point at which the workpiece is machined by applying the laser beam for a predetermined short period of time (<-1) at an intensity (I<-L) which lies between a lower limit (I<-C) at which the generation of a surface plasma starts and an upper limit (I<-D) at which a laser-beam induced detonation wave is generated, whereby the laser radiation is cyclically interrupted and then resumed. In order to enhance the process and to exploit an alternating radiation of the machining point on the workpiece by means of the beams emanating from two energy sources in order to obtain a higher efficiency and quality of the machining process without exceeding the intensity limit (I<-D), the process applies the processing point with the energy radiation of a further energy source in addition to the first laser radiation during the presence of the pla sma such that the start (t<-1) of the said additional radiation takes place after the start (t<-0) of the plasma-induced laser radiation and that the additional radiation uses a multiple of the length of time (<-1) of the predetermined short period of time required for forming the plasma and at an intensity (I<-L2) which avoids a detonation wave induced by the said additional radiation, and that ...