Selective Laser Sintering Forming Process of Spherical Graphite Powder
Effects of different volume ratios of spherical graphite powder to artificial graphite,cladding pretreatment times,and laser energy density on molding accuracy and bending strength of SLS graphite components were investi-gated,and the mechanisms were revealed.The optimal combination of process parameters was further determined by orthogonal experiments to obtain porous graphite skeletons with fine feature sizes.The results indicate that under the certain composition,by increasing the volume ratio of artificial graphite powder to spherical graphite,it contributes to the stacking density and thermal conductivity of the mixed powder as well as the bending strength of SLS graphite com-ponents,which is adverse to molding accuracy.After the graphite powder cladding pretreatment,the effective bonding force between the powders is increased,ensuring the bending strength and molding accuracy of SLS graphite parts under the premise of reducing thermal conductivity and enhancing the stacking density.Finally,a reasonable combina-tion of process parameters was selected to successfully print out a diamond-like porous graphite skeleton with a com-plete structure and a minimum feature size of ϕ1.0 mm,where the relative error of billet size along the X-and Y-axis is controlled below 2%,and that along the Z-axis is 8.25%,and bending strength reaches 2.84 MPa.
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