The production of plastic-metal hybrid components is now being taken to the next level
Announced at the K2010 six years ago and used for a series production part in 2013 for the first time, the production of plastic-metal hybrid components is now being taken to the next level with the copolyamide-based adhesion promoter VESTAMELT® Hylink: The Institute of Plastics Processing in Industry and the Skilled Crafts (IKV) at RWTH Aachen University has developed a process in which the deep drawing and overmolding of the metal component are combined in a single operation in the injection mold, thus automating production. This process necessitates an adhesive joining technique like that provided by VESTAMELT® Hylink.
Normally, metal and plastic parts of hybrid components are bonded using positive or non-positive connecting elements such as screws, rivets or injected form fits. A robust but relatively heavy solution requiring two work stations: The forming and painting of the metal part in the sheet metal processing unit and the joining with the injection-molded part in the plastic processing unit. Time and costs for cleaning and transportation between these two units must also be considered.
By contrast, the adhesion promoter VESTAMELT® Hylink firmly bonds the two components without a further joining technique. This reduces the weight by up to 20 percent and/or increases the performance of the component as compared with conventional solutions. So far, two work steps have also been needed here: Firstly, forming of the metal part coated with the copolyamide-based adhesion promoter and, secondly, overmolding and simultaneous bonding with the plastic component. These two processes are combined in the new innovative process. Forming, bonding, and overmolding take place in a single work step and with a single tool. Eliminating an entire production step reduces costs and the time needed for forming and transportation, and production can be fully automated.
Shorter process chain possible with VESTAMELT® Hylink
Development of the process entitled “Production of structural elements by means of deep drawing and overmolding in the injection mold” by the IKV, with funding from the Otto von Guericke Federation of Industrial Research Associations (grant no. IGF-18075N), was successfully completed with the use of the adhesion promoter VESTAMELT® Hylink, which creates an adhesive joint between metal and plastic in the mold. Polar plastics like polyamides or polyphthalamides are particularly suitable; PA6 and PA66 are frequently used. For improved mechanical properties after conditioning, Evonik offers bio-based VESTAMID® Terra polyamides 610 and 1010 as well as VESTAMID® HTplus polyphthalamide molding compounds for more demanding requirements with regard to temperature, chemical resistance, and low water absorption. This will further expand the range of applications—especially in structural components and other parts for the automotive industry and electronic engineering.