14 Industrial Laser Solutions NOVEMBER/DECEMBER 2016 www.industrial-lasers.com
TECHNOLOGY ADVANCES ALLOW WELDING
COMPLEX PARTS IN HIGH VOLUMES
With today’s high-bright- ness, multi-kilowattsol- id-state laser sources, the concept of remote laser welding with a standoff up to sev- eral hundred millimeters became widely feasible in industrial welding applications.
For this, scanning optics are steering the beam in a 2D space
through a pair of high-speed, galvanometer-driven mirrors (x
and y) and, in the case of 3D applications, a fast focusing mechanism quickly adapts the focus distance (z). These systems are
capable of guiding a laser spot with high precision and can
relocate the spot to any position in their work envelope within
a few milliseconds. If the work envelope of scanner optics is
inadequate to cover the desired area to be welded, an industrial
articulated arm robot can be used to guide the scan head. The
working range can be extended to cover large work pieces and
to access them under well-defined inclination angles.
Recent advancements in scanner optical configurations,
scanner controls, and real-time interfaces to optical sensors
have significantly expanded the application of remote laser
welding. A wide variety of optical magnifications are available
to optimize the optics to the specific laser power and beam
quality desired for a particular application. A previously unavailable optical zoom function that allows a variable spot size at
focus is now available in scanners such as the SCANLAB intelli WELD II. Scanner controllers are available with intuitive user
interfaces and full integration with the guiding robot’s motion
planning, making the previously cumbersome task of programming complicated weld programs simple and user-friendly.
Historically, these systems have been implemented primarily
for lap welding of sheet metal components. In recent years,
manufacturers have exploited the benefits of remote laser weld-
ing to more efficiently weld a number of challenging applica-
tions. The following production scenarios have benefited from
remote laser welding, achieving levels of precision and produc-
tivity not possible with more conventional welding techniques.
Static remote laser welding
In its simplest form, remote laser welding can be implemented
with fixed-position 2D and 3D scanners. Often referred to as
static remote laser welding, the scanner is rigidly mounted in
a fixed location, the un-welded assembly is located within the
scanner field, and the only motion during welding is via the
A rapidly growing application area for static remote weld-
ing is the assembly of lithium battery modules for e-mobil-
ity. These batteries require welding of individual battery cells,
as well as packaging of multi-cell assemblies. These can be
complex assemblies of various materials (copper, aluminum,
nickel, and nickel-plated copper) and multiple layers in a wide
range of thicknesses. Lasers are ideal for most of these welding requirements, and scanners have proven to be a valuable
tool in maximizing speed and accuracy while providing highly
flexible weld geometries.
One example is the welding of the BM W i8 battery modules.
BMW engineers were faced with the challenge of increasing the
tensile strength of the welds connecting the pressure plate to
the frame of the aluminum battery module, while maintaining
the seam quality. This was achieved by implementing scanner
welding with different oscillation patterns. Dr. Rüdiger Daub,
Manufacturing Technologies and Prototype Shop Electric
Energy Storage at BMW, reported that by combining longi-
tudinal and transverse oscillations, the tensile strength was
increased by 35% and porosity was decreased by 40% [ 1].
The applied Blackbird Robotics scan solution (based on intelliWELD) maximizes flexibility in terms of both high mirror dynamics (with frequencies of several hundred hertz) and full control
of the heat input with freely programmable oscillation patterns
and power modulation along the oscillation pattern.
With full Cartesian calibration of the scan field and integrated
drift compensation, even highly position-critical welds can
Remote laser welding