Errico Vito, Campanelli Sabina Luisa, Angelastro Andrea, Dassisti Michele, Mazzarisi Marco, Bonserio Cesare
Department of Mechanics, Mathematics and Management, Politecnico di Bari, Via Orabona 4, 70125 Bari, Italy.
Materials (Basel). 2021 Feb 1;14(3):673. doi: 10.3390/ma14030673.
Direct metal laser deposition (DMLD) is an additive manufacturing technique suitable for coating and repair, which has been gaining a growing interest in 3D manufacturing applications in recent years. However, its diffusion in the manufacturing industry is still limited due to technical challenges to be solved-both the sub-optimal quality of the final parts and the low repeatability of the process make the DMLD inadequate for high-value applications requiring high-performance standards. Thus, real-time monitoring and process control are indispensable requirements for improving the DMLD process. The aim of this study was the optimization of deposition strategies for the fabrication of thin walls in AISI 316L stainless steel. For this purpose, a coaxial monitoring system and image processing algorithms were employed to study the melt pool geometry. The comparison tests carried out highlighted how the region-based active contour algorithm used for image processing is more efficient and stable than others covered in the literature. The results allowed the identification of the best deposition strategy. Therefore, it is shown how this monitoring methodology proved to be suitable for designing and implementing the right building strategy for DMLD manufactured 3D components. A fast and stable image processing method was achieved, which can be considered for future closed-loop monitoring in real-time applications.
直接金属激光沉积（DMLD）是一种适用于涂层和修复的增材制造技术，近年来在3D制造应用中越来越受到关注。然而，由于有待解决的技术挑战，其在制造业中的普及仍然有限——最终零件的质量欠佳以及工艺的低重复性使得DMLD不适用于需要高性能标准的高价值应用。因此，实时监测和过程控制是改进DMLD工艺必不可少的要求。本研究的目的是优化AISI 316L不锈钢薄壁制造的沉积策略。为此，采用了同轴监测系统和图像处理算法来研究熔池几何形状。所进行的对比测试突出表明，用于图像处理的基于区域的主动轮廓算法比文献中涉及的其他算法更高效、更稳定。结果有助于确定最佳沉积策略。因此，展示了这种监测方法如何被证明适用于为DMLD制造的3D部件设计和实施正确的构建策略。实现了一种快速且稳定的图像处理方法，可考虑用于未来实时应用中的闭环监测。
