Different forming directions have significant impact on surface quality in additive manufacturing. This study is aimed at exploring how different forming directions influence surface quality in additive manufacturing (AM). First, experiments were designed to prepare 316L stainless steel by selective laser melting additive manufacturing (SLAAM) in different forming directions. Moreover, the surfaces of samples manufactured by AM were tested using a three-dimensional (3D) surface profiler and a scanning electron microscope. Furthermore, the surface quality was characterized using four parameters, maximum height, S _z ; maximum valley depth, S _v; standard deviation of height, S _q ; and arithmetic average height, S _a. The following results were obtained: (a) different forming directions corresponded closely to upper surface roughness S _a values, the values of S _a being 7.16 and 8.20 μm, respectively. S _a was the smallest among the four parameters; it showed good stability and statistical significance. (b) In the same forming direction, the upper surface roughness values followed the order S _z > S _v > S _q > S _a. S _z was the largest, exceeding 800 μm; the average value S _a was the smallest, reaching 7.36 μm. The values of S _q , S _z and S _v vary when the forming direction changed. Specifically, all of them increased when the forming direction changed from a vertical direction to planar and lateral directions in turn. (c) In different forming directions, the values of S _z , S _v, S _q and S _a varied on different surfaces but their variations were basically similar. Meanwhile, the S _z , S _v, S _q and S _a values of the free surfaces were at least ten times greater than those of the printed surface. In the SLAAM process, it was necessary to select a forming direction reasonably for parts with different dimensional parameters on each side.

中文翻译：

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成形方向对选区激光熔化增材制造316L表面质量的影响

不同的成形方向对增材制造中的表面质量有显着影响。本研究旨在探索不同的成形方向如何影响增材制造 (AM) 中的表面质量。首先，设计了通过选择性激光熔化增材制造（SLAAM）在不同成形方向上制备316L不锈钢的实验。此外，使用三维（3D）表面轮廓仪和扫描电子显微镜对增材制造样品的表面进行了测试。此外，使用四个参数来表征表面质量：最大高度、S _z；最大谷深，S _v；高度标准差，S _q；和算术平均高度S _a。得到以下结果： ( a )不同的成形方向与上表面粗糙度S _a值密切对应， S _a值分别为7.16和8.20μm。S _a是四个参数中最小的；表现出良好的稳定性和统计学意义。 ( b )在同一成形方向上，上表面_粗糙度值的顺序为Sz > _{Sv >} Sq > Sa _。S _z最大，超过800μm；平均值Sa_最小，达到7.36μm。当成形方向改变时，S _q、S _z和S _v的值发生变化。具体来说，当成形方向从垂直方向依次变为平面和横向时，它们都增加。 ( c ) 在不同成形方向上，不同表面上的S _z、S _v、S _q和S _a值有所不同，但变化基本相似。同时，自由表面的S _z、S _v、S _q和S _a值比印刷表面的值至少大十倍。在SLAAM工艺中，需要针对各面尺寸参数不同的零件合理选择成形方向。