Processing And Properties Of Graphite/Polyether Sulfone Resin Composites By Selective Laser Sintering

Selective laser sintering(SLS)is one of the rapid prototyping technologies,and the forming material is one of the key steps of SLS.In the research process of SLS materials,there are some problems such as high price,limitation of material types,etc.Graphite has excellent electrical conductivity,thermal conductivity and self-lubrication.The use of graphite/resin composite powder as raw materials for SLS will give special properties to the sintered parts and broaden their application.This paper proposes the use of graphite as a raw material,the graphite/resin composites were prepared for selective laser sintering experiments,and the selection of binders for the composites,the grouping ratio,the sintering process and the properties of the sintered parts were studied.Two kinds of graphite-resin composite powders were prepared by mechanical mixing method,using graphite powder,polyethersulfone resin(PES)and epoxy resin as raw materials.The thermal properties of the two composite powders were tested by differential scanning calorimetry(DSC)and thermogravimetric analysis(TG),and a single-layer sintering test was conducted on the two composite powders to determine whether the material could be sintered by laser sintering.According to the single-layer sintering test results,the laser sintering forming test was conducted to determine the maximum amount of graphite in the two kinds of composite powders,and the forming quality of different material forming parts was observed.By means of a controlled variable method,laser sintering tensile parts and bending parts of graphite/PES composites with different graphite powders(grouping ratio,graphite particle size)and different sintering process parameters(preheating temperature and laser power)were prepared.Observe the evolution of its microstructure and test its mechanical and electrical properties.With the increase of the mass fraction of graphite in the composite powder,the trend of the tensile strength and bending strength of the laser sintering formed parts,and the influence of the content of graphite on the electrical conductivity of the laser sintered parts were studied.The influence of the particle size of graphite powder on the tensile strength and flexural strength of the composite shaped part was analyzed.With the increase of the preheating temperature,the tensile strength,bending strength and appearance of the formed parts were analyzed.The effect of laser power on the tensile strength,flexural strength,and electrical conductivity of the formed part was investigated.Using graphene as a reinforcing material,the effect of grapheme content on the tensile strength,bending strength and electrical conductivity of the sintered part was analyzed.The orthogonal experiment method was used to optimize the process parameters of laser sintered graphite/PES composites.Using the four-factor three-level design scheme,taking the bending strength and density of the sintered parts as evaluation indicators,the best combination of process parameters was obtained,and the optimized process parameters were applied to the production of graphite/PES composite parts.