Content area
Full text
Keywords
Friction welding, Robotics
Abstract
The forces and torques associated with friction stir welding (FSW) are discussed as they relate to implementation of the welding process with industrial robots. Experimental results are presented that support the conclusions drawn from models developed by others. It is shown that even with heavy-duty industrial robots with high stiffness, force feedback is important for successful robotic FSW. Methods of implementing force feedback are reviewed. Attention is paid to stability issues that arise with variations in tool rotation and travel speed. Successful implementations of robotic FSW are cited.
Electronic access
The Emerald Research Register for this journal is available at www.emeraldinsight.com/researchregister
The current issue and full text archive of this journal is available at www.emeraldinsight.com/0143-991X.htm
Introduction
Friction stir welding (FSW) is a relatively new welding process invented by The Welding Institute (Thomas et al., 1991). In the relatively short time since its invention, the new welding process has found potential applications in a number of industries including: aerospace (military/civilian aircraft, aircraft parts, fuel tanks, rockets), land transportation (tailored blanks, truck bodies, armor plate vehicles, wheel rims, engine and chassis cradles, fuel tankers, motorcycle and bicycle frames), railway (tankers and wagons, container bodies, underground carriages and trams), shipbuilding and marine (panels for decks, sides, bulkheads and floors, helicopter landing pads, offshore accommodation, hulls and superstructures, aluminum extrusions), construction (aluminum bridges, window frames, aluminum pipelines, heat exchangers, facade panels), electrical (bus bars, electrical connectors, electric motor housings, encapsulation of electronics), and gas (tanks and cylinders).
Unlike fusion welding processes, e.g. arc welding, electron beam welding, and laser welding, the FSW process takes place in the solid phase below the melting point of the materials being joined. Advantages that have been cited for the process include: ability to weld alloys that are difficult to weld by fusion welding processes, excellent mechanical properties, low distortion and shrinkage, no fume, porosity or spatter (frequently associated with arc welding), energy efficient, and ability to be used in all positions. Additionally, FSW uses a non-consumable tool, requires no filler wire, or gas shielding, and is tolerant of thin oxide layers.
Because of the large forces and torques associated with FSW, work pieces must be rigidly clamped, and, for singled-sided tools, a backing bar is required. The...