Publications

Application of melt ejection criterion in simulation of micro-machining with laser

Semak, V.V.; Schriempf, J.T.; Knorovsky, Gerald A.; Maccallum, Danny O.

A theoretical criterion defining the threshold pulse energy and beam intensity required for melt ejection is proposed. The results of numerical simulation present dependencies of the threshold pulse energy and beam intensity as functions of laser pulse duration and beam radius. The experimental verification of the proposed criterion is described and the comparison of theoretical predictions and measurements is presented. The criterion is applied for simulation of laser drilling metal foil with thickness in the range 25 μm - 125 μm using a laser beam with 12 μam beam radius and pulse durations 10 ns and 100 ns. The computational results are used to interpret the results of an experimental study of laser drilling of 125 μm aluminum foil using a single mode beam of a XeCl laser performed at the Nederlands Centrum voor Laser Research (NCLR) and the University of Twente. Additional results on Nd:YAG spot welds in pure Ni are also presented.