Theoretical and experimental investigation for micro-channel fabrication using low power CO2 laser

Abstract

CO2 laser being a localised non-contact type machining process depends on the thermal and mechanical properties of a material to a great extent. The scope of this research is to study the effect of process parameters on channel profile of polymethylmethacrylate (PMMA) by CO2 laser (0-25 W). The parameters selected are beam power and scanning speed, keeping assist gas pressure constant. Using the principle of energy balance and assuming complete evaporation of molten material, an analytical model for the depth of cut is developed by considering Gaussian beam energy distribution in three-dimensional coordinate systems. Experimental results obtained at 5 mm thick plate by varying process parameters were compared with the analytical data showing good convergence with a variation of 1.83%. An attempt is made to analyse the variation of channel geometry as a function of process parameters analytically. The present model was developed with consideration of x, y and z coordinates associated with laser machining process and was validated by experimentation and 2D model available in the literature. It was observed that the proposed model shows good convergence with the experimental values. Hence, the proposed model is found to be suitable for prediction of micro-channel depth with precision.