PRODUCTS & SERVICES
Stamping die precision
The design and production of highly complex stamping dies for ultra-thin laminations
require special specification considerations from the OEM and its tooling partner
Oberg has invested
in specialized
equipment to
produce tools for
the latest EV/HEVs
Tools can reach
12ft (3.65m)
and require high
accuracy due
to tolerance
build-up
material utilization and the
complexity of the die. Tools can be
designed to produce individual loose
laminations and/or designed to
stack laminations in the tool through
mechanical interlocking or gluing.
With such a range of
considerations associated with the
development of an EV/HEV
stamping die, it is essential to find a
tooling partner who can collaborate
with an OEM’s engineering team to
specify critical features needed in
Material utilization and die complexity
The use of precision
laminations is a common
requirement shared among
electrified vehicles, no matter
whether they’re fully electric, hybrid
or employ electrification as a standalone
motor, in the drivetrain, in the
axle or on the wheels.
Ultra-thin lamination sheets are
stacked to form the motor’s rotor
and stator and, together, produce
the power required to propel the
vehicle as the magnetic field
generated by the wires wound
through the stator causes the
magnetized bars in the rotor to spin.
Producing laminations for vehicle
electrification requires an ultraprecision
stamping die and, for an
electric or hybrid vehicle application,
more-e icient, thinner laminations
are favored over those used in other
motors of comparable size. The
complexity of the stamping dies
engineered to produce them is also
much higher than a typical tool, as
the length of these tools can reach
12ft (3.65m). A longer length tool
requires greater dimensional
accuracy due to tolerance buildup,
which can occur over the length of
the tool. The additional tooling size
and complexity require that the tool
not only meets the necessary
lamination design requirements, but
also matches the capabilities of the
stamping press and the ability for
toolmakers to maintain and service
a stamping die of this size.
As with any stamping tool, there
is also a trade-o between flat sheet
194 // July 2019 // www.electrichybridvehicletechnology.com
the tool, as well as the specialized
design and manufacturing
capabilities for producing this type
of stamping die. This will ensure that
the dies are capable of e iciently
producing the end-product for the
duration of the program.
Oberg Industries pioneered the
use of tungsten carbide components
in the manufacture of high-speed
stamping dies over 70 years ago,
designing and manufacturing
lamination stamping dies. Oberg has
invested heavily in specialized
equipment to produce tools for the
latest EV/HEV applications,
including accurate and e icient
surface grinding, jig grinding, and
wire EDM machines. Proprietary to
Oberg Industries, its surface
grinding and jig grinding systems
and techniques for the automotive
industry have been developed by an
internal automation group in
conjunction with plant floor machine
operators. A proprietary lift system
was uniquely designed to support
heavier interlocked stacks
incorporating a mechanism to
remove these completed stacks
from the stamping die.
Oberg has added a dedicated cell
in its tooling center that includes
a state-of-the-art decoiler, feed,
straightener, and EV press to
develop and trial the stamping dies
as part of customer acceptance.
Collaboration between the OEM
and its tooling partner is critical to
determining the right specifications
for a long-lasting, high performance
die. Providing an internal team and
stamping die vendor the necessary
time needed to correctly specify the
stamping die helps achieve the
desired motor performance while
also helping meet cost and speed to
market targets, complete with a tool
that plant personnel can e ectively
run and service for years ahead.
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visit: www.magupdate.co.uk/PEHV
can result in trade-offs in die design
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