Abstract SLM (selective laser melting) is a very promising manufacturing method for complicated precision parts of metals and alloys. However, deformation of the bridge structure during fabrication process and post treatment is still a typical problem. In this paper, the deformation of aluminum alloy AlSi10Mg flat bridge structure with various span lengths was investigated by numerical simulation and experiment. The longer the span is, the greater arch bending deformation is. A mechanism of deformation of bridge was discussed. During selective laser melting process, the first layer of bridge bends upward because of no constraint. Then the arch bending results less or no powder on it after powder sweeping for next layer. The bridge bends up further during the formation of the following layer. These alternative phenomena cause the evolution of deformation. However, as the bridge becomes thicker and thicker, its stiffness increases, which leads to the difficulty of its further bending. Therefore, after some layers, there is even no further bending during the forming of following layers with the arch shape kept in the initial layers. Decreasing the laser energy density for the bridge area and using supports are helpful for the reduction of the arch bending deformation.

中文翻译：

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SLM过程中AlSi10Mg平桥结构的动态拱弯机制

摘要 SLM（选择性激光熔化）是一种非常有前途的金属和合金复杂精密零件的制造方法。然而，桥梁结构在制造过程和后处理过程中的变形仍然是一个典型的问题。本文通过数值模拟和实验研究了不同跨度长度的铝合金AlSi10Mg扁桥结构的变形。跨度越长，拱弯曲变形越大。讨论了桥梁变形的机理。在选择性激光熔化过程中，第一层桥由于没有约束而向上弯曲。然后在下一层扫粉后拱形弯曲导致其上的粉末较少或没有粉末。在形成下一层的过程中，桥进一步弯曲。这些替代现象导致变形的演变。然而，随着桥梁越来越厚，其刚度增加，导致其进一步弯曲变得困难。因此，在一些层之后，在形成后续层的过程中甚至没有进一步弯曲，而拱形保持在初始层中。降低桥梁区域的激光能量密度和使用支撑有助于减少拱弯曲变形。