Study On The Design And Manufacturing Process Of Porous Filter Based On Selective Laser Melting

Selective Laser Melting(SLM)is one kind of precise metal additive manufacturing technology,which can effectively manufacture high performance porous structure parts.Due to its unique physical properties and superior mechanical properties,porous structures manufactured by SLM have been widely used in industrial fields.For traditional metal filters,SLM technology with a high degree of freedom of design brings opportunities for structural optimization and innovation.For example,porous structure manufactured by SLM provides a novel filter media for filters.How to take advantage of the performance of porous structures is an important issue for SLM technology to be applied to metal filters.In this dissertation,the design of the porous structure is based on the performance requirements of the filter,and the process optimization of the micro-struts in the porous structure is studied.Finally,a systematic porous filter design method and manufacturing process are explored.The main contents and conclusions of this dissertation are as following:1)SLM manufacturing process optimization of micro-struts in a porous structure.The principle constraints of SLM manufacturing micro-struts are summarized,and the angled micro-struts are analyzed mathematically,which provides a theoretical basis for the design and manufacture of porous structure.From the perspective of scanning methods and energy input,the process of SLM manufacturing micro-struts are optimized.The morphology and dimensional accuracy of the manufactured micro-struts are used as indicators,and combined with statistical analysis and other methods,suitable laser delay parameters are obtained,and the optimized scanning strategy is a spiral 30° scanning strategy.Moreover,determining low laser power,low scanning speed,and small scanning spacing are preferred combinations of process parameters.2)Computational fluid dynamics simulation and finite element analysis of mesh filters.Through the fluid dynamics simulation of the mesh filter,the pressure and flow velocity of the fluid during filtration were obtained,and the finite element analysis of the mesh filter was carried out according to the pressure data.Finally,the stress distribution of the filter is obtained to determine the performance requirements of the filter,and the design rules of the porous filter are proposed.3)The design of porous filter based on performance requirements during filtration.According to the design requirements,the porous structure with different porosity was obtained by topology optimization,and then the tensile test was carried out on the topologically optimized porous structure.The results show that the tensile strength of the topologically optimized porous structure is between 37.5~87.5MPa.The topologically optimized porous structure with a porosity of 90% was selected as the filter media for the porous filter.4)SLM manufacturing and pressure drop-flow performance testing of porous filters.Porous filters with a high dimensional accuracy of the mesh were manufactured using optimized process parameters and laser spot compensation strategy.The pressure drop-flow performance test shows that the topologically optimized porous filter has better pressure drop performance.