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Laser cutting of large diameter hole in aluminum foam is carried out and morphological changes in the cutting section are examined using scanning electron microscopes, energy dispersive spectroscopy and X-ray diffraction. The thermal stress fields in the cutting section are computed in line with the experimental conditions. Finite element code is incorporated in the numerical simulations. It is found that the cut section is free from defects such as large size burrs and dross attachments. The thermal stress predicted is less than the yielding limit of the workpiece. The presence of air trapped within the pores prior to laser irradiation in the workpiece results in the formation of oxide compounds at the cut sections. [ABSTRACT FROM AUTHOR]

In the present study, laser cutting of 7050 aluminum alloy sheets reinforced with Al2O3 and B4C particles are carried out. The cut geometry is examined using scanning electron microscope and the optical microscope. The lump parameter analysis technique is used to formulate and determine the kerf width size. The predictions for kerf width are compared with experimental data. The percentage kerf width size variation along the cut edges is determined and the influence of the laser power level and duty cycle of the laser pulses on the percentage kerf width size variation is examined. It is found that 7050 aluminum alloy reinforced with 20% Al2O3 composite results in relatively large kerf width size as compared to its counter parts that corresponding to 7050 aluminum alloy reinforced with 20% B4C composite. The kerf width size predicted agreed with the experimental data for both composites. [ABSTRACT FROM AUTHOR]

Abstract: CO2 laser cutting of steel sheets is considered and influence of beam waist position relative to the workpiece surface and the workpiece thickness on the striation formation is examined. The kerf width is modeled using a lump parameter analysis. The measurements are composed with the experimental findings. SEM and optical microscopy are conducted to examine the cutting surfaces. It is found that beam waist position has significant effect on the kerf size and as the workpiece thickness reduces, the relative location of beam waist position varies for the minimum kerf width. The microcracks are found in the resolidified material at the cutting surface, which is due to non-uniform and rapid cooling of the resolidified material at the surface. [Copyright &y& Elsevier]