Stress-related process know-how and process optimasiton of plastic welding unsing the example of laser transmission welding

在塑性焊缝质量评价上，目前的重点是考虑准静态、拉伸剪切试验中确定的短期强度。然而，实际构件的不同工作条件会导致不同的应力和应变，例如在激光传输焊缝内。因此，实际的连接响应不同于在实验室条件下观察到的。在与准静态加载相辅相成的动态加载中，可能会出现多轴和长时间作用的加载。目前尚不清楚焊缝是否能承受最大短期抗拉剪切强度，同时也能承受其他载荷。同样未知的是，在不同载荷类型下确定的焊接因素是否相互关联，从而可能从一个到另一个提出建议。对于激光透射焊接，给出了短期和长期焊接因素的相关性。结果表明，焊缝的短期抗拉剪切强度与长期抗拉剪切强度因子呈线性相关。结果表明，在焊接过程中，工艺条件对焊缝形貌和强度有较大影响。一个明显的相关有效的各种塑料焊接工艺，已被证明类似于挤压和热板焊接。因此，该项目的一部分是研究激光传输焊缝的行为如何取决于不同类型的应力和焊接过程的普遍温度场。此外，还应澄清导致可能偏差的原因。在确定焊接过程的温度场的不同应力下，对焊接过程、受影响材料性能和焊缝强度之间的关系进行了研究，从而有可能将激光透射焊接作为其他塑料焊接工艺的先例，并获得可转移的知识。由于激光传输焊接影响的温度场可以形成非常灵活的，因此对激光传输焊接的实例研究为获得可转移的结果提供了很好的要求。因此，本研究应选择激光传输焊接。在不同的应力下，导致最优强度的温度场是不同的。这其中的原因必须从根本上加以考察和理解。此外，通过激光传输焊接产生的时空变化的温度场，以达到最佳的非应力定制焊缝强度。优化方法将是使用具有两个离散激光波长的两条光束路径，两者都由高度动态的光束传输组件引导。

On the plastic weld quality evaluation, the focus is now on the consideration of the short term strength determined in a quasi static, tensile shear test. Different operating conditions of real components, however, lead to various stresses and strains, e. g. within laser transmission weld seams. Thus, the connection responses in reality differs from that observed in laboratory conditions. In use complementary to quasi static loading dynamic, multi axis and possibly loads acting for a long time may occur. It is unknown whether welds bearing maximum short term tensile shear strength withstand also other loads optimally. Also unknown is whether determined under different load types weld factors correlate with each other and thus can be possibly suggested from one to the other. Regarding laser transmission welding, a correlation of the short and long term weld factors are jet presented. It turned out that the short and long term tensile shear strength weld seam factors are linearly related. Further it was shown, that in the welding process prevailing conditions influence the morphology and the weld seam strength considerably. A correlation apparently valid for various plastic welding processes, as has been documented similar to the extrusion and hot plate welding.A part of the project is therefore to investigate how laser transmission weld seams behave depending on different types of stress and the welding process prevailing temperature fields. Moreover it should be clarified what causes possible deviations. Are findings on the relationship between the welding process, the effected material properties and the weld seam strength for different stresses attributed to the temperature field determining the welding process, it is possible to take the laser transmission welding as a precedent for other plastic welding process and to gain transferable knowledge. Since the temperature field effected by laser transmission welding can be formed extremely flexible, the exemplary study of laser transmission welding offers very well requirements to gain transferable findings. Therefore laser transmission welding should be chosen for the proposed investigation. It is expected that temperature fields leading to optimal strength for different stresses will be different. The reasons for this have to be examined and understood fundamentally. Furthermore, by laser transmission welding resulting spatially and temporally varying temperature fields shall be affected to achieve optimal rather stress customized weld seam strengths. The approach of optimization will be the use of two beam paths with two discrete laser wavelengths, both guided by a highly dynamic beam delivery component.