Papers by Author: Xiang Hui Zeng

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Authors: Xiang Hui Zeng, Le Hua Qi, Hua Huang, Xiao Shan Jiang, Yuan Xiao
Abstract: Generating high-melting-point metals droplet is a bottleneck in the area of droplet-based rapid prototyping. In our research, a pneumatic drop-on-demand (DOD) generator was developed which can spray A2024 alloy successfully, and the maximum ejection temperature can reach to 1200°C. Experiments were conducted to examine the influence of the oxygen content on the metal droplet spray. The uniform A2024 droplet was ejected stably under the condition where the oxygen content was less than 25ppm. As the solenoid valve was opened once with different time span, four cases were observed: droplet stream, three droplets, two droplets and one single droplet. A2024 droplets were deposited continuously on top of each other in vertical direction to form vertical columns, which meant the graphite nozzle can be used in experiment. A simple square tube was produced by regulating the droplet generator, which showed the rapid prototyping by high-melting-point droplet deposition is feasible.
Authors: Yan Pu Chao, Le Hua Qi, Xiang Hui Zeng, Jun Luo, Hua Huang
Abstract: In the droplet-based manufacturing process, the accuracy and density of forming parts are determined by experimental parameters such as the velocity and temperature of substrate, droplets spraying frequency, line deposition space and layer thickness etc. Using Sn60-Pb40, the droplets deposition experiment was conducted to investigate the effect of the parameters on the accuracy and density of formed lines, layers and solids on the experimental system. The experiment results showed that the high quality lines were obtained when the overlapping ratio of the adjacent droplets was controlled around 30% by the substrate velocity and droplet spraying frequency, meanwhile,the temperatures of the substrate and droplet were maintained at 270°C and 140°C, respectively. When the lines deposited space was about 90% of droplet diameter and the layer thickness was about 80% of droplet diameter, good deposition results of layers and solids can be obtained. This work has offered experimental guide for metal droplet deposition manufacturing.
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