采用数值模拟与工艺试验相结合的方法，研究了铋锡合金熔融堆积3D打印成形过程温度场变化，以及对 成形件凝固组织演变的影响。结果表明，成形过程中各单元节点会经历若干次热震荡，整个热循环曲线的震荡幅值不断 变小。 先被激活的单元节点所经历的热作用时间较长，且所经历热循环震荡的次数更多；在喷头直径0.2mm，移动速度 2 mm/s，成形间距2mm，搭接率为50%，加热温度165℃，成形底板温度100℃工艺条件下，可得到致密度97.6%的3D 打印金属件；通过对成形金属件截面微观组织进行扫描电子显微镜观察，可以观察到底层、中心和上层3个区域组织存 在明显不同，其中中心区的显微组织为等轴晶组织，该现象与数值模拟分析结果具有一致性。

By means of numerical simulation and process test, the change of temperature field and the effect on solidification structure evolution of BiSn alloy in 3D printing process were studied. The results show that each element node experiences several times of thermal shock during the forming process, and the amplitude of the whole thermal cycle curve becomes smaller and smaller. The first activated cell node experienced longer thermal action time and more times of thermal cycle shock. Under the technological conditions of 0.2 mm diameter of sprinkler head, movement speed is 2 mm/s, forming spacing is 2 mm, lap rate is 50%, 165 ℃ heating temperature and 100 ℃ forming base plate temperature, 3D printed metal parts with 97.6% densification can be obtained. By scanning electron microscope observation of the microstructure of the section of the formed metal, it can be observed that the microstructure of the bottom layer, the center and the upper layer are obviously different, and the microstructure of the central area is equiaxed crystal structure, which is consistent with the results of numerical simulation.