Energy efficient brazing by using the deep penetration effect

在激光材料加工领域，提高加工效率是科学和工业应用领域的研究热点。在激光焊接中，通常采用深熔焊或空间光束调制策略等技术，而这些方法并不是激光钎焊工艺研究的重点。为了影响激光钎焊过程中的温度场，主要研究和发展了双光束工艺和光束整形效果。本工作的目的是证明利用深熔效应可以实现高能量效率的钎焊工艺。如果可能，应避免对样品进行额外的预热。与传统激光钎焊的主要区别是，由于填充材料中的小孔演化，局部但显著提高了对激光能量的吸收。与空间光束调制相结合，这种效应可以用来保证可变和可控的高效热输入。因此，根据填料和基材中产生的温度场以及流体动力学和材料性质来表征润湿行为是必要的。为了验证效率的提高，对小孔工艺的工艺效率进行了评估，并与传统的激光钎焊进行了比较。

Increasing process efficiency is of high interest in science and industrial applications in the field of laser material processing. In laser beam welding, techniques like deep penetration welding or spatial beam modulation strategies are commonly used while those methods have not been in the focus of research in laser beam brazing processes. In order to influence the temperature field during laser beam brazing mainly two-beam-processes and the effect of beam shaping have been investigated and developed.The aim of this work is to prove that a highly energy efficient brazing process can be realized by using the deep penetration effect. If possible, additional pre-heating of the specimen should be avoided. The main difference to conventional laser beam brazing is the local but significantly higher absorption of the laser power due to keyhole evolution in the filler material. In combination with a spatial beam modulation this effect can be used to guarantee a variable and controllable efficient heat input. Therefore, the characterization of the wetting behavior depending on the produced temperature fields in the filler and base material and the fluid dynamics as well as material properties is necessary. In order to verify the efficiency improvement the process efficiency is evaluated for the keyhole processes and is compared to conventional laser beam brazing.