esides the already mentioned pro-
duction processes for optimising
spring performance, we now wish to
describe the special processes provid-
ed by SCHERDEL to ensure the best
possible product quality and greater
customer satisfaction.
Nitriding process
The practice of steel nitriding, which is
commonly used in metal refining, can
also be used to a certain degree for
springs. This guarantees an increase in
the load stress which acts on the
spring, thus enhancing the service life
and improving wear protection. Nitrid-
ing processes can be carried out for oil-
tempered valve spring wires as well as
for corrosion-resistant spring wires. The
processes vary depending on the
spring shape, wire diameter and mater-
ial.
Shot-peening and blasting
processes
For many years now, SCHERDEL has
been using steel shot peening to ex-
tend the useful life of its valve springs.
All the parameters of this process are
continuously optimised to achieve the
best possible results for each spring.
This includes assessing and monitoring
the results using an x-ray diffractometer
to measure residual stresses. A scan-
ning electron microscope provides a
detailed image of the created spring
surface. Shot peening can be carried
out both in bulk and individually. A
combination of several different peen-
ing methods carried out one after the
other is suitable for particularly highly
stressed springs.
Blasting processes using either glass
beads or aluminium oxide are extreme-
ly popular due to the increasing de-
mands for clean and burr-free technical
springs. The blasting time and media
are always adapted to the spring
geometry.
Setting process
As previously mentioned, the relax-
ation characteristics and thus the toler-
able load stress are key criteria for
springs. Besides the increase of possi-
ble stress loads, high load stability can
be achieved even at high temperatures
throughout the entire life of a spring.
Setting consists of compressing springs
to a fixed height for a certain period of
time while at room temperature or an
elevated temperature. This is followed
by a cooling phase and the release of
stress in the spring. An exceptional
cost-benefit-ratio can be achieved by
adapting the setting process to the re-
quired spring characteristics.
6
MECHANICAL ENGINEERING – MANAGEMENT –
TECHNOLOGY & PRODUCT DEVELOPMENT
–
NEWS AND INFORMATION
RESEARCH & DEVELOPMENT
Special processes ensure
B
Special SCHERDEL processes enhance product q
springs and compression-loaded spring systems
SCHERDEL –
crowned ʻSupplier of
the Year 2011ʼ not
once, but twice
The SCHERDEL
Group
was re-
cently named ʻSupplier of the
Year 2011ʼ by the vehicle manu-
facturer MAN Truck & Bus AG
and the automotive supplier
WOCO Industrietechnik GmbH.
WOCO is also a specialist in the
field of vibration reduction and in-
dustrial seals. Both awards were
presented in recognition of out-
standing quality, cost awareness,
logistics and technical expertise.
MAN particularly praised
SCHERDEL for providing a high
level of technical support and
quick and efficient solutions. This
long-term cooperation has result-
ed in technically-advanced en-
gine components which help to
reduce exhaust emissions and
fuel consumption. The WOCO
Group justified their decision to
award SCHERDEL this illustrious
prize by stating that the time be-
tween the initial request for a
solution from SCHERDEL
INNOTEC GmbH and DFTR
Röslau and the first prototypes
being completed was just two to
three weeks.
(
dk
)
