This equipment provides high flexibility and unrestricted reach up to 8. 2 ft. ( 2. 5 m) for applications
beyond flat linear joints. Advanced controls with
embedded force control ensure high-accuracy, in-contact motion. Sophisticated motion software
permits linear welding in arbitrary patterns and
circular and square paths. Robotic FSW systems are
designed to adapt to production changes and to be
easily reconfigured for new applications.
Custom-designed systems handle high-volume
production of large aluminum panels, girders, and
trusses. System configurations, which include gantry style, column and boom, and seam welder, vary
depending on the application demands.
In a fully automated system, the machine control,
specially developed for FSW, manages all critical
variables and can be monitored remotely from any
PC using a standard Ethernet connection. Large-
scale equipment is used in aerospace (cryogenic
tanks for rockets, space capsules, airframe struc-
tures), marine and shipbuilding (panel welding,
long linear welds, stiffened panels), oil and gas (fuel
tanks, storage tanks), and transportation (railcars,
truck frames) applications.
No matter the size or style of equipment, any fab-
ricator that is interested in this type of welding pro-
cess needs to understand some of the following ba-
sic fundamentals before investing in the equipment.
Welding Speed. The welding speed of the system
depends on the welding tool, joint type, alloy, mate-
rial thickness, and stability of the welding machine
and fixture station.
Welding Force. FSW equipment must be designed
for high welding forces. In FSW, a cylindrical shoul-
dered tool with a profiled pin is rotated and plunged
into the joining area between two pieces of sheet or
plate material. Parts must be securely clamped in a
way that prevents the joint faces from being forced
apart. A 0.20-in.- (5-mm-) thick 6082 T6 butt joint
can be welded at low speed with a specific down-
force, but the same welding at 20 FPM ( 6 m/min.) re-
quires a downforce that is eight to 10 times higher.
Surface Contact. Good surface contact with the
workpiece must be maintained constantly. Other-
wise, friction will decrease, and the quality of the
weld will suffer. The best welding result comes from
equipment having force control. With force control,
the system monitors downforce to maintain force
accuracy throughout the welding process. This en-
sures full contact with the material at all times.
Tool Design. Welding tool design is critical in FSW.
Optimizing tool geometry to produce more heat or
achieve more efficient “stirring” offers two main
benefits: improved breaking and mixing of the ox-
ide layer and more efficient heat generation, yield-
ing higher welding speeds and better quality.
Tool materials should have relatively high hard-
ness at elevated temperatures and retain this hard-
ness for an extended period. The combination of
tool material and base material is critical to the
tool’s operational lifetime. When welding single-
sided extruded profiles in the Al 6000 series with
a 0.20-in. (5-mm) material thickness, it’s typical to
weld nearly 5,000 FPM (1,500 m/min.) with one tool,
which corresponds to more than 100 panels.
Resistance to wear (durability) is an important
aspect of tools for welding steel. To apply FSW in
steel or other high-temperature materials, the tool
material must withstand the high temperatures (
approximately 1,200 degrees F) that occur during the
process. In these applications, tools with a polycrystalline cubic boron nitride tip are the most effective.
In a modular FSW system, the welding head design is
based on the alloys to be welded and their thickness.
The length of the machine is adjusted according to the
length of the pieces to be welded. Clamping systems
and fixtures are typically made separately based on the
application needs. The modularity of this design brings
FSW to a wider range of applications and users.
Complex structures require a flexible working envelope
provided by FSW systems that use a robot modified for
FSW was designed to join aluminum and other nonferrous metals. Today it also can be used for carbon steel and other
materials. Dissimilar materials also can be joined with it.