A numerical approach for a comparative study of laser drilling process under single and repetitive pulse

Abstract

An axisymmetric model is developed to study laser drilling process under a single pulse as well as repetitive laser pulse. The laser pulse irradiated on the surface of the workpiece is volumetric and Gaussian in nature. The laser irradiated surface is subjected to convective‐radiative boundary condition while rest of the surfaces are insulated. Finite volume method is used to discretize the domain under consideration. The resulting algebraic equations are solved with the help of the tridiagonal matrix algorithm to find temperature distribution throughout the domain. The enthalpy‐porosity method is used to track the solid‐liquid interface generated during the laser melting process. Convective heat transfer occurs inside the generated melt pool. The current model is first used to validate the results of the existing literature and as the results agreed well, further studies are made to find out the advantages of using repetitive laser pulse over single pulse laser source for laser drilling process for the same laser energy and total heating duration. Vaporization has been avoided during the process and metal removal occurs through melting only. The present numerical model can provide some insight for practical laser drilling process.

Effects of Beam Mode on Hole Properties in Laser Processing

“…Important factors in laser material processing include the laser power, beam radius, pulse duration, defocusing distance, repetition rate, atmospheric pressure, and beam mode. Optimizing the machining parameters for the pulse duration, repetition rate, and combined pulse has been the focus of considerable interest [3][4][5][6][7][8]. A growing number of theoretical and experimental works have also investigated the effects of atmosphere pressure on the processed material [9][10][11].…”