Laser Keyhole Brazing
Laser Keyhole Brazing
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激光锁孔钎焊
DOI：
10.1002/phvs.202100013
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Woizeschke
中科院分区：
文献类型：
--
作者：
Woizeschke
1400℃。采用了一维线性和二维圆周振荡策略。振荡策略影响振荡的几何展开和激光光路的有效轨迹长度。这影响了激光的运动路径和运动速度，从而影响了激光与材料的局部相互作用时间以及熔池和界面的温度分布。后者对于基材中不需要的熔化和润湿过程都很重要。因此，了解振动参数对温度场的影响是控制该过程的关键。测量界面上的温度分布的可能性有限，如果可能的话。然而，可以测量熔池表面的温度分布来指示熔池内和界面上的温度分布[6]。因此，对于所考虑的过程，假设表面温度分布更均匀，界面温度分布更均匀。为了确定熔池表面的温度分布，基于测量的非接触式测量系统可以降低激光的局部移动速度，或者更确切地说，缩短局部停留时间。与在恒定的激光功率和钎焊速度下没有振荡的工艺相比，后者减小了熔池深度。铜焊的另一个重要方面是润湿过程。预热衬底有利于润湿[4]。在传统工艺中，这是通过激光光斑直接照射衬底来实现的，激光光斑的直径被选择为显著大于金属丝直径。这在具有深度渗透效应的铜焊时是不可能的，因为聚焦的激光束会由于高强度而熔化衬底材料。因此，预热必须通过熔化的铜焊材料的热传导来实现。通过将小孔钎焊工艺与光束振荡相结合，成功地实现了珠板钎焊试验(在平板基板上应用钎料)，钎料完全熔化，基片材料不熔化(见图1，右)。为此，采用了以镀锌钢为基材的AlSi12钎料。温度测量表明，熔池中的温度远高于焊料的熔化温度(580℃)，激光钎焊是一种获得高质量焊缝的方法。传统的方法是基于利用激光在其表面的简单菲涅尔吸收来熔化焊接材料。传统的铜和铝基钎焊材料反射高百分比的激光束，导致工艺效率降低，因为只有很小比例的激光束被吸收并对工艺做出贡献。
1400 C. Both one-dimensional linear and two-dimensional circular oscillation strategies were used [5]. The oscillation strategy influences the geometrical expansion of the oscillation and the effective trajectory length of the laser beam pathway. This influences the movement path and the movement speed of the laser beam, and thus the local interaction time between the laser beam and the material as well as the temperature distribution in the melt pool and at the interface. The latter is important regarding both unwanted melting in the substrate and the wetting process. Therefore, knowledge of the influence of the oscillation parameters on the temperature field is essential to controlling the process. Measuring the temperature distribution at the interface is only possible to a limited extent, if at all. However, it is possible to measure the temperature distribution on the surface of the molten pool to indicate the temperature distribution both within it and at the interface [6]. For the considered process, it is thus assumed that a more homogeneous temperature distribution on the surface correlates with a more homogeneous temperature distribution at the interface. For the determination of the temperature distribution on the molten pool surface, non-contact measuring systems based on a measurelocal movement speed, or rather shortens the local dwell time, of the laser beam. The latter reduces the melt pool depth compared to processes without oscillation at otherwise constant laser power and brazing speed. Another important aspect of brazing is the wetting process. Preheating the substrate favors wetting [4]. In conventional processes, this is realized through the direct irradiation of the substrate by the laser spot, whose diameter is selected to be significantly larger than the wire diameter. This is not possible when brazing with the deep penetration effect because the focused laser beam would melt the substrate material due to the high intensity. Preheating must, therefore, be realized via heat conduction through the molten brazing material. By combining the keyhole brazing process with beam oscillation, a beadon-plate brazing test (brazing material application on a flat substrate) with a complete melting of the brazing material and without melting in the substrate material was successfully realized (see Fig. 1, right). For this purpose, an AlSi12 brazing material was used with galvanized steel as the substrate material. Temperature measurements showed that the temperatures in the molten pool were well above the melting temperature of the solder material (580 C) at overLaser beam brazing is one way of producing seams with high visual quality. Conventional methods are based on melting the brazing material using the simple Fresnel absorption of the laser beam on its surface. Conventional copper and aluminum-based brazing materials reflect a high percentage of the laser beam, leading to decreased process efficiency as only a low proportion of the laser beam is absorbed and contributes to the process.
DOI：
--
发表时间：
2017
期刊：
影响因子：
--
作者：
V. Schultz;W. Cho;F. Vollertsen
通讯作者：
F. Vollertsen