The effect of deposition pattern on thermal stress and deformation in laser solid forming

A 3-D indirect-coupled finite-element model was developed for describing the transient thermal/stress field during Laser Solid Forming (LSF) process. The effect of the deposition patterns, raster, outside-in spiral and Hilbert fractal patterns, on the thermal field, thermal stresses and substrate deformation during LSF process was examined. It is found that the transient temperature gradient and the maximum equivalent stress in the LSFing part decreased gradually in LSF process. The transient temperature gradient and the maximum equivalent stress were small using Hilbert fractal deposition pattern on comparison with those using the other patterns. The larger residual stress and the smallest substrate deformation is obtained using the raster deposition pattern, and the smaller residual stress and the largest substrate deformation is produced using Hilbert fractal deposition pattern.