Joining by using pin-like structures in welding processes

在焊接工艺中使用销状结构来产生形状配合接头代表了一种将联合收割机粘合不相容的聚合物组合的创新方法，从而拓宽了可能的聚合物组合范围。在不使用添加剂或广泛的表面预处理的情况下，通过连接不相容的半结晶热塑性塑料，可以实现局部适应的部件特性。此外，使用销状结构允许半结晶和无定形热塑性塑料的组合，以实现例如通过光学透明元件的永久功能化。除了连接粘合不相容的聚合物外，该工艺的优点还可应用于焊接强度低的粘合剂，例如纤维增强热塑性塑料。在这种情况下，销状结构可以有助于修改的纤维取向，垂直于连接平面，从而更高的粘结strengths.The建议的项目的目的是通过在焊接过程中的销状结构的连接机制的相互依赖性的基本调查。为此，应用振动焊接以及超声波焊接技术，这两者都基于通过摩擦输入的能量。尽管潜力很大，但这种新型连接技术目前还不清楚材料、工艺和所得粘结性能之间的相互依赖性。研究项目中的全面实验研究与基于模型的分析相结合，可以制定材料组合和工艺处理的一般要求。因此，从根本上分析了决定性的工艺参数、结构几何形状以及发生的热机械相互作用对最终接头的影响。与振动焊接技术相比，使用超声波焊接技术能够生产更小的销结构，从而提高接头的承载能力，并且该工艺也可以用于更小的部件。此外，超声波焊接继续将其自身与振动焊接原理区分开，因为不同的振荡方向用于能量输入和结构生成。这使得在结构化过程中更好地识别特定于工艺的相互作用。借助本项目中获得的知识，可以建立对通过销状结构以及一般结构化和连接策略进行连接的全面理解。这些允许将方法转移到进一步的材料和连接工艺中。

The use of pin-like structures for the generation of form-fit joints in welding processes represents an innovative approach to combine adhesion incompatible polymers and thus broadens the possible polymer combination spectrum. Without the use of additives or extensive surface pre-treatments, locally adapted part properties can be achieved by joining incompatible semi-crystalline thermoplastics. In addition, the use of pin-like structures allows the combination of semi-crystalline and amorphous thermoplastics, to enable for example a permanent functionalization by an optically transparent element. Besides joining adhesion incompatible polymers, the benefits of the process can be applied on bonds with low weld strength, e.g. fibre-reinforced thermoplastics. In this case, the pin-like structures could contribute to a modification of the fibre orientation, perpendicular to the joining plane, and thus to higher bond strengths.The aim of the proposed project is the fundamental investigation of interdependencies of the joining mechanism by means of pin-like structures in welding processes. For this purpose, vibration welding as well as ultrasonic welding technology are applied, which are both based on energy input by means of friction. Despite the high potential, interdependencies between material, process and resulting bond properties are currently unknown for this novel joining technique. The comprehensive experimental investigations within the research project, in combination with a model-based analysis, enable the development of general requirements for the material combinations as well as for the process handling. Therefore, the effects of decisive process parameters, of the structure geometry as well as of the occurring thermomechanical interactions on the resulting joint are fundamentally analysed.In comparison to the vibration welding technology, the use of the ultrasonic welding technology enables the production of smaller pin structures whereby the load capacity of the joint can be increased and the process can also be made accessible for smaller parts. Furthermore, ultrasonic welding continues to differentiate itself from the vibration welding principle since different oscillation directions are used for the energy input and the structure generation. This allows an improved identification of process-specific interactions during structuring.With the help of the knowledge gained within this project, a comprehensive understanding of the joining by means of pin-like structures as well as general structuring and joining strategies can be established. These allow the transfer of the methodology to further materials and joining processes.