Industrialization of directed energy deposition (DED) process relies on the development and implementation of a quality assurance system that makes the process reliable and repetitive. One of the geometrical characteristics that needs constant monitoring and control during any DED process is the height of the deposited layer. In this paper, a multidirectional layer height monitoring system relying on the laser triangulation principle that has been developed for real-time direct measurement, in contrast to the majority of the sensor systems that derive layer height based on melt pool temperature, is presented. Existing commercial laser triangulation systems are unidirectional, which hinder the flexibility of the material handling system, like industrial robot, in most of the cases. An additional challenge lies on the integration with the deposition head due to its form, size, and extreme working conditions. Therefore, a novel configuration of laser triangulation sensors that enable multidirectionality and limit shadowing effect has been developed at Fraunhofer IAPT. In this paper, the development of such a sensor with a focus on the mechanical design has been presented. The sensor is designed for operation at high temperature and harsh environmental conditions close to the build zone. The developed sensor has been successfully tested for the powder-based laser metal deposition system. In-process layer height measurement and control are possible with this sensor, thereby enabling digitalization and quality assurance during the build process. 3D point cloud generated using this sensor can be used for the dimensional deviation measurement and also for downstream processes like machining. Such an in-process quality measurement and assurance system negates a postmeasurement step, thereby saving cost and time and ensuring quality.

中文翻译：

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通过多向高度监测传感器系统对定向能量沉积过程进行数字化

定向能量沉积（DED）工艺的工业化取决于质量保证体系的开发和实施，该体系使工艺可靠且重复。在任何DED过程中需要不断监视和控制的几何特征之一是沉积层的高度。与大多数基于熔池温度得出层高的传感器系统相比，本文提出了一种基于激光三角测量原理的多方向层高监测系统，该系统已开发用于实时直接测量。现有的商用激光三角测量系统是单向的，这在大多数情况下会妨碍物料搬运系统（如工业机器人）的灵活性。另一个挑战在于由于沉积头的形式，尺寸和极端的工作条件而与沉积头集成在一起。因此，在Fraunhofer IAPT上开发了一种新型的激光三角测量传感器，该传感器可实现多方向性并限制阴影效应。在本文中，已经提出了以机械设计为重点的这种传感器的开发。该传感器专为在靠近构建区域的高温和恶劣环境条件下运行而设计。研发的传感器已经成功地测试了基于粉末的激光金属沉积系统。使用此传感器可以进行过程中层的高度测量和控制，从而在构建过程中实现数字化和质量保证。使用此传感器生成的3D点云可用于尺寸偏差测量，也可用于诸如加工之类的下游过程。这样的过程中质量测量和保证系统消除了后测量步骤，从而节省了成本和时间并确保了质量。