Bringing FSW to the Production Floor
FSW equipment comes in varying configurations,
from simple CNC production machines the size of
a dining room table to the largest spacecraft welding tool built, which stands 170 feet tall, is 78 ft. in
diameter, and weighs more than 3 million pounds
(see Figure 3).
For general production of simple butt/lap joint
welds, a modular system offers flexibility and economy and brings the technology to a broader base
of users (see Figure 4). These systems are designed
for welding depths from 0.02 to 2. 56 in. (0.5 to 65
mm) and for production of small to medium-sized
components and small batches in varied sizes, such
as electronic enclosures, flat panels, and heat exchangers. The welding head travels on heavy-duty
linear bearings and is driven by a rack-and-pinion
drive system. Modular systems are built for easy
integration with larger fixtures, rotary units, and exchangeable clamping systems.
Robotic systems tackle more challenging applications (see Figure 5). Designed for complex
joints, particularly in the aluminum 6000 series, robotic systems feature full FSW integration. The robot is modified for the FSW process and can apply
a downforce of up to 13 kN ( 2,922 ft.-lbs.), suitable
for welding 5xxx aluminum up to 0.24 in. ( 6 mm).
In friction stir welding, a rotating, nonconsumable, pin-shaped tool penetrates the material and generates frictional heat, softening the material and enabling the weld
to be completed in a single pass.
Friction stir welded panels have perfectly flat, hollow profiles.
NASA’s heavy-lift rocket, the Space Launch System, being manufactured in conjunction with Boeing, is a high-profile
FSW application. The Vertical Assembly Center (VAC) is a giant circumferential welding system that uses FSW to preci-sion-weld the fuel tank structures for the rocket. Its weld head and clamp positional accuracy and repeatability hold
a weld tolerance of less than 0.015 in. (0.38 mm).
Material thicknesses from 0.02
to 2. 56 in. (0.5 to 65 mm) can be
friction stir welded from one side
at full penetration, without
porosity or internal voids
(often a challenge when arc