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A D V A N C E D
M A T E R I A L S
&
P R O C E S S E S | J U L Y / A U G U S T
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Boston. The company is using design-
driven manufacturing to 3D print cus-
tomspike plates, based on an individual
runner’s biomechanics. Using a propri-
etary process to collect race simulation
data from Team New Balance runners,
the company’s research lab applies
advanced algorithms to translate this
information into an optimized design
that can be additively manufactured
on an EOSINT P 395 system. This plastic
laser-sintering technology from EOS of
North America Inc., Novi, Mich., allows
designers to produce complex geome-
tries that cannot be created using tradi-
tional manufacturing techniques.
Long before the spike plates are
additively manufactured, or even de-
signed, the lab collects each runner’s
biomechanical data using a force plate,
in-shoe sensors, and a motion-capture
system. The motion-capture system
helps determine the relationship of the
foot to the force plate, creating a 3D
vector recreation of the foot strike. The
in-shoe sensors show discrete pressure
information over the course of the run-
ner’s foot strike and how the runner’s
foot interacts with the shoe. When a
particular part of the foot exhibits high
pressure values, it generally indicates
that the associated 3D vector is import-
ant to that area of the shoe at a specific
moment.
“A simple example is in the toe
area. Generally, when you see high pres-
sure there, it corresponds to a force that
is pushing toward the heel to create a
propulsive force forward. We use para-
metric modeling software to process
this data and distribute the position of
the spike plate traction elements, cal-
culate the orientation and adjust the
size of the elements, and incorporate
specific runner preferences into the de-
sign,” says Sean Murphy, senior manag-
er of innovation and engineering.
The designer is then responsi-
ble for performing the CAD cleanup
necessary to create the final product,
including touching up model surfac-
es and making adjustments to accom-
modate the full-size range of the spike
plate. Once the final geometry has been
verified, CAD files are converted to .stl
files and uploaded to the EOSINT sys-
tem for production. With traditional
manufacturing, each spike-plate style
requires several injection molds for
various sizes, each costing thousands
of dollars. These molds run thousands
of plates before being retired or re-
placed, often annually, by a new mold
indicating a new model. Currently,
the laser-sintered batch sizes produce
around four unique plate pairs and take
five to six hours to manufacture.
While traditional track spikes
are commonly made of thermoplastic
polyurethane and polyether block am-
ide, New Balance worked with high-
performance materials manufacturer
Advanced Laser Materials, Temple, Tex-
as, part of the EOS family, to develop a
proprietary nylon blend. Spike plates
are grown in the EOS system from the
custom-blend nylon powder, coupled
with tailored laser conditions, and yield
maximum engineering properties such
as tensile and flex moduli while mini-
mizing build time.