Abstract Components fabricated by the deposition and solidification of molten droplets have the common defect of rough surface, which are mainly caused by the poor bonding and inadequate evolution of the interface. To address such a problem, the pileup process of vertical column by successive droplets was simulated under an axisymmetric system, where the evolution of interface was captured by Front Tracking Method (FTM). The positive enthalpy was calculated to investigate the heat accumulation effect on the structure of vertical column. Shape parameters were established for modeling bonding states, and the ideal bonding was obtained by linear interpolation of these parameters. The average length of ravine was proposed to evaluate the surface quality, and the effects of superheat and Weber numbers on surface quality of ideal structure were investigated. The results show that the positive enthalpy increases gradually under constant deposition rate, and the excessive bonding occurs on the head of vertical column due to the heat accumulation. The mathematic calculation model proposed to acquire the ideal bonding state and the variation rules of surface quality for ideal structure, which is affected by superheat numbers and Weber numbers, can provide access to improve the forming precision in droplet based manufacture.

中文翻译：

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连续液滴形成的垂直柱结构的计算研究

摘要 熔滴沉积凝固制备的构件具有表面粗糙的共同缺陷，主要是由于界面结合不良和演化不充分造成的。为了解决这个问题，在轴对称系统下模拟了连续液滴垂直柱的堆积过程，其中界面的演变通过前跟踪方法（FTM）捕获。计算正焓以研究热积聚对垂直柱结构的影响。建立了用于模拟键合状态的形状参数，并通过这些参数的线性插值获得了理想的键合。提出了沟谷的平均长度来评价表面质量，研究了过热度和韦伯数对理想结构表面质量的影响。结果表明，在恒定沉积速率下，正焓逐渐增加，由于热量的积累，垂直柱头部出现过度结合。所提出的数学计算模型可获取受过热度数和韦伯数影响的理想结构表面质量的理想结合状态和变化规律，可为提高微滴制造中的成形精度提供途径。