Prediction of material removal rate due to laser beam percussion drilling in aluminium sheet using the finite element method

Laser beam percussion drilling is used for the rapid fabrication of small diameter hole in a wide variety of engineering materials. A computational thermal model to predict the material removal rate will help to enhance the cost effectiveness of LBPD process especially for material like aluminium which has very low machinability during laser beam machining due to its adverse optical and thermal properties. An axisymmetric finite element method-based thermal model incorporating the temperature dependent thermal and optical properties as well as the phase change phenomena has been developed to determine the transient temperature distribution in thin aluminium sheet, which is further used to obtain the material removal rate (MRR). The predicted values of MRR have been compared with the self conducted experimental results. It was found that the peak power has the dominant effect on MRR followed by thickness of sheet, pulse width and pulse frequency.