1st ICAI 2020

International Conference on Automotive Industry 2020

Mladá Boleslav, Czech Republic

locally with high temperature gradients.The heat flowmelts the plastic at themetal-plastic interface. Afterwards the plastic solidifies at the metal surface. For both technologies a pre-treatment of the metallic surface is required, either using an adhesion promoter or surface structures to anchor the plastic. (Rösner, 2014; Klotzbach et al, 2017) Within the study, adhesive bonding and thermal direct joining with lasers as well as with induction heat sources were applied to connect bio-based and petro-chemical plastic with lightweight metal. Table 1 gives an overview of the technological characteristics. The development of adhesion based joining processes includes much more than the connection realisation itself (Figure 1). After a proper joint design the surfaces of metal and plastic have to be analysed and pre-treated. The type of pre-treatment depends on the joining process, the load level and configuration as well as other requirements like aging stability, degree of automation and productivity. For industrial use the joining process itself has to guarantee reproducible connection qualities with long term stability also under climate changes during use. Only then the process is ready for use.

Table 1: Overview of investigated processes and their characteristic properties

Thermal direct joining with laser radiation

Adhesive bonding Thermal direct joining with induction (HPCi) any combination thermoplastic + metal

Flexibility thermoplastic + metal Joining principle adhesive curing induction heat + pressure laser heat + pressure Pre-treatment plastic + metal metal metal Process time slow very quick quick Source: own elaboration

Figure 1: Process chain of joint fabrication based on adhesion and on combination of adhesion and form-fit

Source: own elaboration

2. Experimental setup During part design, an effective choice of material and suitable joining method requires concrete data on possible combinations. This is especially true for bio-plastics that are not yet standard in many application fields. Thus, the literature on joining of bio-materials is quite limited, especially for mixed-material combinations with metals. Furthermore, it is important to rely on data created under comparable conditions, which is usually also difficult when data from different literature sources has to be brought together. To overcome this, several material and process combinations were

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