Downsizing stationary shoulder tools versus system robustness and gap tolerance
By Markus Weigl (Grenzebach Maschinenbau)

Coming from conventional tools with rotating shoulders to stationary shoulder variants already allows a significant reduction of the tool and also the weld seam dimensions. A further downsizing of these multipart designs for welding applications at thin walled components as well as filigree structures enables FSW to compete against other joining technologies, such as laser beam welding. However all scaling down measures implicate well-understood correlations of tool geometry, system robustness and resulting gap tolerances in order to realize adequate durability plus seam quality under industrial conditions.
In that context the present article discusses the current state of the art regarding downsized stationary shoulder tools and especially the challenges and potentials in terms of pin break prevention. Furthermore the gap tolerance of such small tools during butt joints in thin walled 5xxx and 6xxx Aluminum alloys will be analyzed.