Due to the layer-based nature of the powder bed fusion (PBF) process, part surfaces oriented in space at varying angles with respect to the build direction are differently affected by a wide array of manufacturing-induced phenomena (staircase effects, spatter, particles, etc.), which can significantly influence the functional behaviour of such surfaces, and choices for post-processing where needed. For assessing surface topography of PBF surfaces most researchers have looked at surface texture parameters (profile - ISO 4287 and areal - ISO 25178−2). Texture parameters provide useful summaries of surface-wide properties, but do not allow the analysis to focus on specific topographic formations of interest. On the contrary, feature-based characterisation encompasses a series of recently introduced methods that allow to isolate and characterise specific topographic formations of interest starting from topography datasets acquired with conventional areal topography measurement solutions. In this work, the topography of electron beam powder bed fusion (EBPBF) surfaces as a function of orientation with respect to the build direction was investigated using a combined approach consisting of both texture parameters and feature-based characterisation. A custom-designed test part featuring surfaces at different orientations was measured with a focus variation instrument. A feature-based characterisation pipeline was implemented for the identification, isolation and geometrical characterisation of spatter formations and particles present on the as-built surfaces. The surfaces deprived of the identified features were then characterised by means of conventional ISO 25178−2 texture parameters. The results confirm that combining feature-based characterisation with conventional analysis through texture parameters creates new perspectives for looking at EBPBF surfaces, thus better supporting future research endeavours aimed at achieving a more comprehensive insight on the nature of EBPBF surfaces. For the first time quantitative results are provided on number, shape and localisation of spatter and other particles in EBPBF surfaces as a function of build orientation, and texture parameters are provided that describe the fabricated surfaces in a more reliable way as particles and spatter formations have been removed.

由于粉末床熔化（PBF）过程的基于层的性质，在空间中相对于构建方向以不同角度定向的零件表面会受到各种各样的制造引起的现象（楼梯效应，飞溅，颗粒等）的不同影响。等），这会严重影响此类表面的功能行为，并在需要时进行后期处理的选择。为了评估PBF表面的表面形貌，大多数研究人员研究了表面纹理参数（轮廓-ISO 4287和面-ISO 25178-2）。纹理参数提供了有用的表面范围属性的摘要，但不允许分析集中在感兴趣的特定地形形成上。反之，基于特征的特征描述包括一系列最近引入的方法，这些方法允许从使用常规面积特征测量解决方案获取的特征数据集开始，对感兴趣的特定特征进行分离和特征化。在这项工作中，使用包含纹理参数和基于特征的组合方法，研究了电子束粉末床聚变（EBPBF）表面的形貌作为相对于构建方向的方向的函数。使用聚焦变化仪测量了定制设计的具有不同方向表面的测试零件。实施了基于特征的特征流水线，以识别，隔离和几何表征飞溅物形成物和竣工表面上存在的颗粒。然后，借助常规的ISO 25178-2纹理参数对缺少识别特征的表面进行表征。结果证实，将基于特征的特征与通过纹理参数进行的常规分析相结合，为观察EBPBF表面创造了新的视角，从而更好地支持了旨在对EBPBF表面性质进行更全面洞察的未来研究工作。首次提供了基于构建方向函数的EBPBF表面中飞溅物和其他颗粒的数量，形状和位置的定量结果，并提供了纹理参数，以更可靠的方式描述了制造的表面，因为颗粒和飞溅物具有被删除。