Bond Technologies has taken on the task of producing a robust, repeatable Refill Friction Stir Spot Welding (RFSSW) system, which brings higher performance and lower costs to the automotive industry and other industries working with aluminum alloys. This new tool compares favorably with riveting and resistance spot welding as the methods of choice for automotive chassis welding.
“With this breakthrough, Bond now offers a performance and cost-competitive alternative to self-piercing rivets and resistance welding of aluminum sheets. Our Refill Friction Stir Spot Welding machine can be mounted to a robot or, as a stand-alone unit. Test results show that cycle time of less than one second are achievable for automotive aluminum sheets.”
–Dave Hofferbert, President of Bond Technologies
RFSSW is a solid-state joining process developed and patented by our friends at Helmholtz-Zentrum Geesthacht (HZG) in Germany, with whom Bond has a working partnership.
The process was developed using the tools and techniques of friction stir welding (FSW) in a new way, making possible solid-state spot welds in aluminum alloys that are flush with the sheet, in contrast to earlier uses of FSSW to make spot welds. FSSW fundamentally leaves a keyhole, which reduces its strength. By independent manipulation of the probe, shoulder and clamping ring, both axially and rotationally, a solid zone of “stirred” material is created between the sheets, yielding higher strength. Like other friction processes, this weld has extremely high quality and repeatability, with proper controls.
Until now, the RFSSW process has been limited by the speed at which a weld can be made. Bond overcame this obstacle by designing a rigid, compact and light weight system, capable of higher force, torque and speed than has been possible previously. We also paid attention to the changeover time for tooling, reducing it to 30 seconds. Additionally, the Bond RFSSW machine is lighter and more versatile than other such devices.