Effects of Process Parameters on the Forming of Coated Sand by Selective Laser Sintering

The coated sands(100/200 mesh) with different resin contents were designed and prepared for selective laser sintering.The forming processes of selective laser sintering were performed for investigating the effects of sintering parameters(spreading powder,laser power and scanning speed,etc) on the forming of coated sand.The results show that the tensile strength of the laser-sintered parts was obviously reduced with the increase of the layer thickness of spreading powder.The effective layer thickness of spreading powder of 100/200 mesh coated sand is 0.15mm~0.25mm.The tensile strength of sintered parts is substantially increased by increasing laser power or decreasing scanning speed,especially for low resin content.Moreover,the orthogonal experimental results show that the effect of process parameters on the tensile strength of laser-sintered parts are: laser power﹥scanning speed﹥layer thickness of spreading powder.The optimal process parameters is 40w laser power,2000mm/s scanning speed and 0.15mm layer thickness of spreading powder,the tensile strength of the laser-sintered original parts is 0.72MPa,increasing by 120% when compared with the present studies,which can satisfy the requirement for the fine structure of the laser sintering sand(core) strength.