Functionalization of series components by joining laser-sintered with injection-molded parts: Weld seam characteristics in vibration welding

Laser sintering (LS) enables cost-effective production of small batches as well as complex functional integration due to the direct build-up process without the need for specific tools. Further, geometrical restrictions are non-existent or only very limited. The combination of LS components with series components, for example, from injection molding (IM), allows to follow the growing trend of customizing and time tightening in the development process as well as the implementation of application-specific functions in small quantities. In order to exploit these potentials, reproducible and mechanically highly loadable joining processes are required for joining LS and IM components. Vibration welding represents a highly robust and stable process, which in this study is investigated for the production of LS-IM joints. Thereby, the focus is on the existing interactions between the two joining partners in the bonding zone. The investigations show that high bond strengths (in the area of the base materials) can be achieved by vibration welding. In contrast to other joining processes such as infrared welding, the bond quality is only marginally affected by the welding parameters. The characteristics of the weld seam are striking. While on the IM side a typical seam structure as known in the literature results, it deviates significantly for the LS side. Independent of the weld parameters, a highly oriented microstructure is recognizable that exhibits transcrystalline structures. In addition, less melt is generated and displaced into the weld bead for the LS component. Both aspects have been attributed to the different material properties of the joining partners.