Skalon Mateusz, Meier Benjamin, Gruberbauer Andreas, Amancio-Filho S T, Sommitsch Christof
IMAT Institute of Materials Science, Joining and Forming, Graz University of Technology, Kopernikusgasse 24/1, 8010 Graz, Austria.
Joanneum Research, Materials-Institute for Laser and Plasma Technology, Leobner Straße 94, 8712 Niklasdorf, Austria.
Materials (Basel). 2020 Feb 10;13(3):808. doi: 10.3390/ma13030808.
The following work presents the results of an investigation of the cause-effect relationship between the stability of a melt pool and the roughness of an inclined, unsupported steel surface that was 3D-printed using the laser powder bed fusion (PBF-L/M) process. In order to observe the balling effect and decrease in surface quality, the samples were printed with no supporting structures placed on the downskin. The stability of the melt pool was investigated as a function of both the inclination angle and along the length of the melt pool. Single-track cross-sections were described by shape parameters and were compared and used to calculate the forces acting on the melt pool as the downskin was printed. The single-melt track tests were printed to produce a series of samples with increasing inclination angles with respect to the baseplate. The increasing angles enabled us to physically simulate specific solidification conditions during the sample printing process. As the inclination angle of the unsupported surface increased, the melt-pool altered in terms of its size, geometry, contact angles, and maximum length of stability. The balling phenomenon was observed, quantified, and compared using roughness tests; it was influenced by the melt track stability according to its geometry. The research results show that a higher linear energy input may decrease the roughness of unsupported surfaces with low inclination angles, while a lower linear energy input may be more effective with higher inclination angles.
以下工作展示了一项关于熔池稳定性与采用激光粉末床熔融（PBF-L/M）工艺3D打印的倾斜、无支撑钢表面粗糙度之间因果关系的调查结果。为了观察球化效应和表面质量下降情况，样品打印时在朝下表面未放置支撑结构。研究了熔池稳定性与倾斜角度以及熔池长度的函数关系。单道横截面通过形状参数进行描述，并进行比较，用于计算打印朝下表面时作用在熔池上的力。单熔道试验打印出一系列相对于基板倾斜角度逐渐增大的样品。角度的增加使我们能够在样品打印过程中物理模拟特定的凝固条件。随着无支撑表面倾斜角度的增加，熔池在尺寸、几何形状、接触角和最大稳定长度方面发生了变化。通过粗糙度测试观察、量化并比较了球化现象；根据其几何形状，球化现象受熔道稳定性的影响。研究结果表明，较高的线能量输入可能会降低低倾斜角度无支撑表面的粗糙度，而较低的线能量输入在较高倾斜角度下可能更有效。
