Hybrid forming of sheet metals with long Fiber-reinforced thermoplastics (LFT) by a combined deep drawing and compression molding process

In this article, a newly developed method for forming metal sheets together with long fiber-reinforced thermoplastics (LFT) to hybrid parts is presented. The idea of combining two different materials in one part is nothing new, but most of the existing processes use at least separate production techniques for each material and an additional joining operation. The special characteristic of this new process is realized by a combined forming tool for both sheet metal and LFT to create a hybrid part with only one necessary and simultaneously executed process step. Besides contact to the punch, the metal sheet is also formed by the molten LFT material, which behaves like a hydraulic fluid in hydroforming processes. With this method, it is possible to reduce the thickness of sheet metal components by adding a LFT reinforcement structure. The interface connection between the metal sheet and LFT is realized by using a bonding agent, which is previously applied to the metal sheet via coil or powder coating. To achieve this hybrid forming process, new tool and sealing concepts have been developed and the corresponding process parameters were identified and optimized. As a result, the innovative process offers a cost- and time-efficient solution for multi-material lightweight design.