This study investigates a metal laser direct-writing additive manufacturing process for potential in-space applications.The feasibility of stable deposition under various gravitational conditions—specifically at angl...This study investigates a metal laser direct-writing additive manufacturing process for potential in-space applications.The feasibility of stable deposition under various gravitational conditions—specifically at angles of 0°,90°,and 180°between the deposition direction and gravitational acceleration,and under zero-gravity—is demonstrated.The analysis reveals that a stable metal deposition layer can be formed under different gravity conditions by establishing a strong liquid bridge connection with the substrate;however,the direction of gravitational acceleration significantly affects the cross-sectional morphology of the deposition layer.By comparing different parameters,it is found that the best cross-sectional morphology can be obtained when the wire feeding speed is 120 mm/min and the ratio to the moving speed is 1.0.Notably,a higher wire feeding rate correlates with an increased temperature gradient within the heat-affected zone.On this basis,a thin-walled cylindrical piece printed at a 90°angle between the deposition gravity directions exhibits an outer surface cylindricity of 0.294mm,a size deviation range of-0.168 mm to 0.126 mm,a maximum size deviation of 0.168 mm on the outer surface,and a surface roughness of less than 8.142μm.The results indicate that this process produces printed parts with high surface quality and geometric accuracy.Tensile tests on the printed parts demonstrate that they possess excellent mechanical properties.This study provides valuable insights and a meaningful exploration of future in-orbit metal manufacturing.展开更多
A reconfigurable modular robot was developed for a free-flying robot project. This robot was composed of 6 same modular joints and one gripper. In order to save space and cost for transporting it into the space, the r...A reconfigurable modular robot was developed for a free-flying robot project. This robot was composed of 6 same modular joints and one gripper. In order to save space and cost for transporting it into the space, the robot should be folded overall and locked. A big central hole in the modular joint was designed for the placement of the cables and plugs in the robot arm, which prevented them from damage of high temperature, radiation in the space environment and the motion of the robot. Multiple sensors were integrated into the fully modular joint, such as joint torque sensor, joint position sensor and temperature sensors, which made the joint more intelligent. A zero gravity experimental system was developed to verify the functions of the robot under zero gravity environment.展开更多
文摘This study investigates a metal laser direct-writing additive manufacturing process for potential in-space applications.The feasibility of stable deposition under various gravitational conditions—specifically at angles of 0°,90°,and 180°between the deposition direction and gravitational acceleration,and under zero-gravity—is demonstrated.The analysis reveals that a stable metal deposition layer can be formed under different gravity conditions by establishing a strong liquid bridge connection with the substrate;however,the direction of gravitational acceleration significantly affects the cross-sectional morphology of the deposition layer.By comparing different parameters,it is found that the best cross-sectional morphology can be obtained when the wire feeding speed is 120 mm/min and the ratio to the moving speed is 1.0.Notably,a higher wire feeding rate correlates with an increased temperature gradient within the heat-affected zone.On this basis,a thin-walled cylindrical piece printed at a 90°angle between the deposition gravity directions exhibits an outer surface cylindricity of 0.294mm,a size deviation range of-0.168 mm to 0.126 mm,a maximum size deviation of 0.168 mm on the outer surface,and a surface roughness of less than 8.142μm.The results indicate that this process produces printed parts with high surface quality and geometric accuracy.Tensile tests on the printed parts demonstrate that they possess excellent mechanical properties.This study provides valuable insights and a meaningful exploration of future in-orbit metal manufacturing.
文摘A reconfigurable modular robot was developed for a free-flying robot project. This robot was composed of 6 same modular joints and one gripper. In order to save space and cost for transporting it into the space, the robot should be folded overall and locked. A big central hole in the modular joint was designed for the placement of the cables and plugs in the robot arm, which prevented them from damage of high temperature, radiation in the space environment and the motion of the robot. Multiple sensors were integrated into the fully modular joint, such as joint torque sensor, joint position sensor and temperature sensors, which made the joint more intelligent. A zero gravity experimental system was developed to verify the functions of the robot under zero gravity environment.
