Mold production by selective laser sintering of resin coated sands

Small sand molds for aluminum casting were produced by selective laser sintering (SLS) of pre-coated sands. A diode laser source with a rectangular laser beam spot was used to perform single and multi-layer processing tests. Subsequently, small sand molds were produced and tested in casting operations. Single layer processing was performed by changing laser power, scan rate and distance of the processed surface from the beam focus. In multiple layer processing, some process changes were made to achieve a perfect joining of adjacent layers. More changes were necessary for the mold production so as to compensate the negative cooling effect of the metallic frame during the sand laser heating. At the end of the process optimization, final molds showed good soundness even if the morphology of internal mold surfaces was affected by the layering procedure