Resistance Projection Welding Using Wire Mesh Inserts: Joining Hollow Profiles to Sheet Metals

For large-scale manufacturing of profile-intensive vehicle bodies, a suitable joining process for hollow profile–sheet metal joints is required. These joints pose challenges related to minimizing plastic deformation while ensuring low, localized heat input to preserve the properties of high-strength steels. Conventional resistance spot welding often leads to profile deformation due to concentrated force and heat input and the lack of mechanical backing. For this reason, CD-welding tests on sandwich structures consisting of hollow profile-sheet metal with a wire mesh interlayer used as natural projections are conducted. This enables multiple small welds with localized heat input and welding times below 10 ms. This study investigates the influence of the weld parameters electrode force and charging energy, and illustrates that as the electrode force increases, plastic deformation increases up to the point of failure above 24 kN. In this regard, support structures and inserts made of copper and plastic, as well as novel welding electrodes with lateral profile contacts, are being investigated. Joint quality is evaluated based on setdown, electrical resistance, shear strength, and plastic deformation of hollow profiles. The highest shear tensile forces of up to 47 kN were achieved using 60 projections and an inner copper support structure.