Advanced joining techniques for hybrid parts made of metal and bio-based plastics

The market of bio-based and bio-degradable plastics is growing due to governmental regulations and society needs. However, implementation of bio-plastics into standard production processes poses challenges, often caused by limited understanding of its process behaviour. This also applies to automotive applications. To improve acceptance a comparative study about joining of polylactic acid (PLA) to metal was done. The paper discusses joint strength behaviour of adhesive bonding, ultrasonic joining, and thermal direct joining using laser and induction heat sources. As a reference, petrochemical plastics like polypropylene (PP) and polyethylene terephthalate (PET) were joined too. The results show the influence of the joining process parameters to the transferable load. With optimized parameters the joint strength of multi-material connections using bio-plastics are comparable to the reference materials. These new results facilitate the production of complex hybrid parts made of bio-plastics and metal.