Laser
Seam Welding
Laser
Edge software and hardware address the unique
requirements
of hermetic sealing applications.
•
Specialized
coordinate transformations reduce programming complexity
•
Sophisticated
look-ahead capability minimizes acceleration in small part geometries
•
Position
Synchronized Output ensures consistent beam overlap across entire part profile
•
Direct-drive
noncontact linear and rotary axes provide high throughput and consistent performance
in 24/7 operating environments
part
profile is generated off-line and the speeds are manually
Laser
welding has been used extensively in the medical
adjusted
on a block-by-block basis to achieve the desired
industry
for the hermetic sealing of packages designed for
performance
goals. Using the A3200 kinematics capability,
implantation
into the body. More common uses for this
the
part profile can be generated directly from a CAD
process
have been in the manufacture of pacemakers and
drawing
and executed on the controller. This greatly reduces
defibrillators.
The process of applying the weld to the seams
programming
time and program complexity, and permits
of
these devices requires precise firing control of the laser to
rapid
changeover to alternate part profiles.
maintain
a consistent overlap in the laser welding pulses
while
traversing the perimeter of the part.
Flexible
Part Alignment
Programming
in part coordinates and executing the
Kinematics
Improves Part Quality
kinematics
in real time enables the specification of the point
Aerotech's
Automation
3200 controller with built in
of
rotation at run time. Programs generated with a post-
kinematics
capability greatly reduces the complexity of laser
processor
must assume a fixed point of rotation. This
seam
welding applications. Programming in part coordinates
requires
special attention to the fixturing of the part to ensure
allows
the application to take advantage of the A3200's
that
the actual point of rotation coincides with the
sophisticated
path planning and multi-block look-ahead
coordinates
of the point used to generate the motion profile.
features.
The welding speed automatically can be reduced to
Any
variation between these two coordinates can adversely
minimize
high accelerations that are produced as a function
affect
weld quality. Using the online kinematics feature of
of
small radii features on the part. The resultant optimized
the
A3200, a different point of rotation could be specified for
velocity
and
each
part, if desired. The rotation point can easily be
position
profiles
calculated
with a vision system and used in the kinematics
are
then run
equations
on a part-by-part basis.
through
the
kinematics
in real
time
to generate
Direct
Control of Laser Output
The
kinematics program has access to the commanded
motion
for the
coordinates
of the X/Y part profile in real time. This coordinate
physical
axes. On
information
can be used within the transformation to control
less
capable
the
firing of the laser at precise locations along the weld seam.
controllers,
the
This
high-speed direct control of laser firing ensures consistent
This
graph shows an example of how
beam
spot overlap over the entire part profile, resulting in
multi-block
look-ahead optimizes
improved
weld quality and lower defect rates.
velocity
and position profiles.
X'
Position/Velocity
X
Position/Velocity
Real-Time
Y'
Position/Velocity
Y
Position/Velocity
Kinematic
C
Position/Velocity
Transformation
XY
Rotation Point
Laser
Control
Real-time
kinematic transformation improves process quality and reduces programming time.