Hybrid RSW Welding of Composite Materials

Authors: Pawel Sokolowski, Pawel Kustron, Marcin Korzeniowski, Tomasz Piwowarczyk, Aleksandra Malachowska, Monika Nowakowska

DEVICE FOR HYBRID RSW WELDING OF COMPOSITE METAL – POLYMER – METAL SANDWICH MATERIALS

The technological offer concerns the device and the technology of hybrid resistance spot welding (RSW) of composite Metal – Polymer – Metal sandwich materials. The device and technology have been partially submitted for patent protection in the Polish Patent Office under the number P.438142 and as part it is confidential know-how.

TECHNICAL DETAILS

Composite metal sheets MPMS (Metal-Polymer-Metal sandwich) / MPC (Metal-Polymer Composites) are modern construction materials characterized by very good ratio between mechanical properties and functionality to weight which overcomes the conventional sheet materials. These composites are usually made up of three layers: external cladding made of metal (steel, aluminum, etc.) and an internal, usually polymer core. MPMS materials are gaining interest in the automotive, aviation and construction industries. However, these materials have an important limitation – it is difficult to join them quickly and with high quality. Conventional joining (market available) techniques are currently used: riveting or clinching joints. However, these methods are time-consuming and do not provide adequate mechanical properties of the joints, and thus do not fully exploit the potential of MPMS/MPC materials. The solution to the problem of joining MPMS/MPC composite sheets is offered here, as a device and technology of hybrid RSW welding of composite materials. The technology uses ultrasonic waves to initially soften and remove the non-conductive internal layer, and then the permanent connection of composite sheets can be done similarly as in RSW technology. The whole process takes place in one and fast operation (the ultrasonic system is integrated with the welding electrodes).

The sequence of making a connection is as follows:
a) initial pressure of the moving electrode,
b) generating ultrasounds and introduction of ultrasonic vibrations to the materials, in order to heat and plasticize the polymer core only,
c) turning on the welding current and creating a permanent connection (weld).

APPLICATIONS MARKETS
The device and the technology can be used in the automotive, aviation, construction industries and generally wherever it’s justified to join modern MPMS/MPC composite sheets.

INNOVATION ADVANTAGES
• possibility of joining MPMS/MPC composite sheets with conventional materials, e.g. steel/aluminum sheets,
• the possibility of one-sided welding of MPMS/MPC composite sheets,
• elimination of mechanical connection (e.g. clinched connections, blind riveting without holes).