Investigating the Effect of Process Parameters and Scan Strategy During Laser Forming of Thin Open Celled Aluminium Foam

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The present study provides detailed investigation on the effect of various laser processing parameters and scan strategy during laser forming of thin open-celled aluminium foam. Previous research on laser bending showed that metal foams can be formed by laser processing, but it is very difficult to form the metal foams mechanically owing to their brittle nature. The 2D Laser forming operation was carried out using 2 kW fiber laser with laser power and scanning speed as input process parameters while bending angle was calculated as an output parameter. The effect of laser power, scan speed, number of scans and scan distance from the edge on bending angle of the foam were analyzed and presented. It was observed that the laser processing showed a decrease in bending angle with an increase in scan speed except for 1750 W power, where after 12500 mm/min the bending angle did not follow the trend. The bending angle decreased with increase in number of scans probably due to strain hardening effect. The effect of scan distance from the edge was different for lower process parameter combinations {600 W, 2500 mm/min} and {1000 W, 4000 mm/min}, where the bending angle was maximum for a distance of 20 mm from edge in 1400 W, 7500 mm/min scan speed. For 1750W, 11000 mm/min bending angle was maximum for 80 mm distance from edge. The SEM analysis showed that the major concern associated with laser forming of open-celled Aluminium foam is foam melting. EDS and XRD analysis showed that formation of different oxides and compounds of Aluminium increases with increases in laser power and scan speed. Micro-Computed Tomography (micro-CT) analysis confirmed the absence of crack during laser forming and the pore density variation during laser forming was clearly visible between laser processed zone and the parent material zone.