Research On The Key Technology Of Powder Spreading Device For Lunar 3D Printer

With the development of deep space exploration technology and aerospace technology,mankind’s determination and confidence to explore the vast universe are also growing.The construction of a lunar base to conduct deep space exploration missions using the moon as a springboard is highly valued by scientific research institutions in various countries.It will be a promising research direction to complete the construction of lunar base infrastructure at a lower cost and combine laser additive manufacturing technology with the concept of in situ utilization of lunar soil.But so far,there are still some problems to realize it: the lunar surface environment is very bad,and the equipment is difficult to work;The quality of powder spreading process will directly affect the quality of molded parts.However,there are few studies on the powder spreading process with lunar soil as the material at present.The process of powder spreading with lunar soil is still unclear,and the powder spreading effect of the powder spreading device needs to be improved.In view of the above problems,this paper designs a lunar surface 3D printer powder spreading device considering the impact of the low gravity environment on the lunar surface,studies the lunar soil powder spreading process using the discrete element method,and explores the influence of the powder spreading process parameters on the quality of the lunar soil powder bed,which provides a theoretical reference for realizing the In-situ manufacturing of the lunar surface.The main research contents and methods are as follows:Considering the interference of the low gravity environment of the moon surface to the lunar soil powder spreading,combined with the existing equipment design and working principle at home and abroad,the overall plan of the powder spreading equipment is determined,which is divided into forming bin and lifting device,powder spreading module,powder storage and supply module,powder recovery module and framework.The three-dimensional model of each module is established,and the design of each part of the powder spreading module is mainly analyzed according to the theoretical formula to ensure the rationality of the structural design.The force between the lunar soil and the powder roller is analyzed.According to the results,the theoretical formulas of the powder spreading process parameters and the powder bed compressibility,the force and offset of the previous molding layer,and the radius of curvature are established,and the normal mechanical model of irregular lunar soil particles is supplemented;The movement of lunar soil particles in the shaping silo was analyzed,and the mechanical model of the particles was established;According to theoretical calculation,the influence of powder bed quality on the density,shrinkage,warpage and surface accuracy of molded parts is explored.The parameters of CUG-1A simulated lunar soil were calibrated to determine the discrete element model;The orthogonal test was designed,and the numerical simulation was carried out by using the EDEM simulation software to explore the influence of the powder spreading process parameters of the powder spreading scraper and the powder spreading roller on the powder bed density,surface roughness,and the offset of the previous molding layer,so as to provide a reference for determining a better range of process parameters.To explore the flow performance of lunar soil particles in the process of flour spreading,according to the numerical simulation results,analyze and obtain the influence rule of flour spreading process parameters on the particle flow characteristics,further clarify the changes in the process of flour spreading of lunar soil,and provide reference for obtaining lunar soil with better flow performance in flour spreading.