In-Situ Manufacturing of Metal-Plastic Composite Structures by Process Combination of Hydroforming and Injection Molding

摘要

The application of lightweight structures, especially in the automobile industry, is a major factor for reduction of fuel consumption and related C02 emissions.Beside the implementation of lightweight materials such as ultra-high strength steel, aluminum, magnesium or fiber-reinforced polymers there is an upcoming demand for hybrid materials.Metal-plastic hybrid structures are an efficient solution to use the right material at the right place in installation space.The current state of the art of production technologies for hybrid structures is characterized by metal components being produced separately in conventional forming processes.These parts are engaged in the molding die, and the core injection molding process is only responsible for shaping the plastic ingredient and joining.Such process chains are complex and extensive.This paper shows a new approach of the process combination of conventional metal forming technologies and the application of the fluid plastics from molding process as a forming media regarding hydroforming.Thus, the objective is a process combination of metal forming and injection molding in one die and one process step to produce highly complex hybrid metal-plastic components in a highly efficient way.The first development step combined the processes of deep drawing of sheet metals and injection molding.Thus the plastic melt is also used as forming media regarding hydroforming and it was successfully merged into one tool and one process.The second development step increased the complexity to a combination of gas forming and injection molding for tubes and closed profiles.In order to perform this process combination, the gas forming technology was integrated into an injection molding press.One main challenge in such hybrid structures is the joint strength in interface between the metal and polymer component.To substitute chemical bonding agents such as Vestamelt(R) comprehensive investigations were carried out in surface structuring of metal tubes such as sandblasting, knurling and laser structuring.