Novel monitoring system for spatially resolved topographical measurement of laser-based processes
Novel monitoring system for spatially resolved topographical measurement of laser-based processes
复制标题
用于基于激光的过程的空间分辨形貌测量的新型监测系统
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
H. Singpiel
中科院分区：
文献类型：
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作者：
J. Weberpals;P. Berger;T. Graf;J. Trein;H. Singpiel
近年来，随着高聚焦性激光系统的引入，对激光材料加工定量监控系统的需求也在增加。事实上，目前的激光系统具有很强的可聚焦性和约1 μm的波长，在许多应用领域都表现出很高的创新潜力，例如可以将焊接深度调整到甚至很小的材料厚度。 然而，这些优点的可用性是有限的，因为合适的工艺窗口在增加的焊接速度下被显著地限制。在某些应用中，甚至比发射10 µm辐射的激光器还要高。 因此，对热材料加工过程进行可靠的实时监测至关重要。一种新的有前途的方法是利用热辐射表面的偏振相关发射特性来获得关于表面几何结构的详细信息。除了熔池的尺寸之外，凸起的焊缝或其突起是工业应用中重要的质量特征。通常熔池结构或接缝缺陷由毛细管的几何形状和动力学引起。本文介绍了一种新的监测系统，以确定三维锁孔或切割前的几何形状的基础上的热表面的偏振热辐射。除了可以确定毛细管的空间倾斜度外，该传感器还可以用于在激光材料加工过程中监测熔池结构或即将出现的接缝缺陷，或者通过过程控制来防止后者。在过去的几年中，随着高聚焦性激光系统的引入，对激光材料加工定量监测系统的需求也在增加。事实上，目前的激光系统具有很强的可聚焦性和约1 μm的波长，在许多应用领域都表现出很高的创新潜力，例如可以将焊接深度调整到甚至很小的材料厚度。 然而，这些优点的可用性是有限的，因为合适的工艺窗口在增加的焊接速度下被显著地限制。在某些应用中，甚至比发射10 µm辐射的激光器还要高。 因此，对热材料加工过程进行可靠的实时监测至关重要。一种新的有前途的方法是利用热辐射表面的偏振相关发射特性来获得关于表面几何结构的详细信息。除了熔池的尺寸之外，凸起的焊道或其下的焊缝的尺寸也可以被测量。
In the last years, parallel to the introduction of laser systems with high focusability the demand for quantitative monitoring systems for laser material processing has increased. Indeed, current laser systems with strong focusability and wavelengths of about 1 µm exhibit a high innovation potential in many application ranges, for example the possibility of adjusting the welding depth to even small material thicknesses. However, the usability of these advantages is limited because the suitable process windows are considerably constricted at increased welding speed. In some applications even more than for lasers emitting radiation of 10 µm. Therefore, a reliable real-time monitoring of thermal material processing is of vital importance. A new promising approach is the exploitation of the polarization-dependent emission characteristics of hot radiating surfaces to get detailed information about geometrical surface structures.In addition to the dimensions of the melt pool, the raised welding bead or its underfill are important quality characteristics for industrial applications. Generally melt pool structures or seam imperfections result from the geometry and the dynamics of the capillary. This paper introduces a novel monitoring system to determine the three-dimensional keyhole or cutting front geometry based on the polarized thermal emission of the hot surface. Besides the possibility to ascertain the spatial inclination of capillaries, this sensor can be used to monitor melt pool structures or upcoming seam imperfections during laser material processing or to prevent the latter by an in-process control as well.In the last years, parallel to the introduction of laser systems with high focusability the demand for quantitative monitoring systems for laser material processing has increased. Indeed, current laser systems with strong focusability and wavelengths of about 1 µm exhibit a high innovation potential in many application ranges, for example the possibility of adjusting the welding depth to even small material thicknesses. However, the usability of these advantages is limited because the suitable process windows are considerably constricted at increased welding speed. In some applications even more than for lasers emitting radiation of 10 µm. Therefore, a reliable real-time monitoring of thermal material processing is of vital importance. A new promising approach is the exploitation of the polarization-dependent emission characteristics of hot radiating surfaces to get detailed information about geometrical surface structures.In addition to the dimensions of the melt pool, the raised welding bead or its unde...