Research On Selective Laser Sintering Of Polystyrene/Polyester/Glass Fiber Composites And Molding Process

Polystyrene(PS)for selective laser sintering(SLS)has been widely used in the field of manufacture prototypes because of its advantages of low shrinkage,wide range of processing temperature and low price.However,because of the poor mechanical properities of PS sintered parts,it is difficult to meet the molding requirements of functional parts and large thin-walled parts.In this paper,in order to improve the quality of PS sintered parts,the material modification to PS and SLS sintering process parameters of the modified material were studied.First of all,based on the quality requirements of molded parts,the materials modified by PS powder were studied.Because polyester fiber(PET)and glass fiber(GF)materials have good toughness and mechanical properties,the co-modification of PS with PET and GF double fiber was carried out.Secondly,the PS/PET/GF ternary composites were prepared by mechanical mixing and thermal analysis was carried out.It was confirmed that the glass transition temperature of the composites was 92?.Through single-factor sintering experiments,it was determined that the layer thickness for the PS/PET/GF ternary composite sintered part was ranged from 0.17mm to 0.25mm,the scanning pitch range was ranged from 0.21mm to 0.29mm,and the scanning speed was ranged from 1300mm/s to 21 00mm/s.At the same time,the influence of different process parameters on the quality of the sintered parts was obtained.Through the material ratio experiment,the optimum mass ratio of PS:PET:GF ternary composites suitable for SLS process was determined to be 8:1:1.Finally,through a series of sintering experiments,the effect of the coupling process parameters on the dimensional accuracy,density and bending strength of the PS/PET/GF ternary composite sintered parts was studied.The orthogonal experiment was carried out by selecting the main process parameters of delay thickness,scanning distance and scanning speed which affect the sintering quality.The strength and accuracy were used as evaluation indicators to obtain the best sintering of PS/PET/GF ternary composites.The best process parameters for the quality are layer thickness of 0.23mm,scan pitch of 0.21mm and scan speed of 1700mm/s.The ultimate strength of the sintered part was 11.18MPa,and the relative error in the Z dimension was 2.93%,which effectively improved the quality of the molded part.The research results have certain reference value for the sintered PS functional parts.