fastening & assembly solutions and technology - Approved Business

FAST OCTOBER 2011
PRODUCT REVIEW: Quick release fasteners
The quick acting fastener
is making a comeback
Market forces are causing OEMs to rethink fastening strategy by reviving a system that
had for years been thought of as too expensive for general commercial use. Special correspondent
Sam Kerr-Smiley reports
In recent years, the quarter turn has
been widely used to fasten automotive
noise shields. These components have
been specified for the removable panels
that are fitted beneath vehicle engine
bays to provide additional sound deadening.
When the vehicles are serviced, these
panels are removed to gain access to
parts of the engine that require attention,
especially with commercial vehicles with
shorter service intervals.
The quarter turn was originally developed
in 1932 when William Dzus created
his famous fastener for use in the
fledgling US aviation industry; although,
at that time, its use was primarily
military.
Designed for fastening panels over
areas where regular servicing or frequent
access was required the quarter-turn
became a widely used standard with
many applications; indeed it’s remained
in production ever since – at the time of
Dzus’ death in 1964 there were around
20
6000 variations – but although many
tried to develop it to reduce overall inplace-cost,
the quarter turn, with its
expensively, separately milled external
spiral cam has, until recently, been
unable to bridge the cost gap caused by
Far Eastern bulk production of nuts, bolts
and screws, therefore remaining an
expensive proposition for OEM’s.
Which is really just what they want to
avoid, particularly in these constrained
times – but show an OEM a way they can
demonstrably improve the benefits avail-
Fast turn studs are unlocked in seconds
able to their customers and they will pay
attention. This is exactly what Unifast did
when it was given the opportunity to
design a fastening system to secure gearbox
noise shields for commercial vehicle
giant Iveco – taking the quarter turn principle,
re-developing it for cost effective
high volume production into the Fastturn
quick acting system.
Fast-turn, as the child of both demand
and innovation, uses new production
techniques, which combined with
advances in materials and tooling, allows
Unifast to manufacture the system on
high speed, fully automated processes
and deliver a product that is capable of
beating the in-place-cost (IPC) of traditional
systems by, in many cases, as much
as 60 per cent.
Design and production
The traditional quarter turn fastener has
been re-designed and re-engineered into
a thoroughly modern joining system, and
while the research and development outlay
was significant it has ultimately
delivered an integrated fastening solution
with benefits across production and
application.
Luca Bergadano, Unifast’s spokesman
explained: “Advanced manufacturers are
now able to use a cold forming process to
make the entire stud, significantly reducing
waste and time, and most importantly,
completing it without needing to mill
on the external spiral cam.”
Cold forming delivers near, or absolute,
net shape, eliminating the need for
secondary operations and as it uses 100
per cent of the metal it leaves no scrap or
swarf, generating significant savings in
materials cost, as well as through the production
process by reducing down time
needed for cleaning and maintenance.
Larger volumes, especially over longer
production runs, will clearly demonstrate
improved throughput and significant savings
on materials usage.
“We employ cold forming,”
Bergadano continued, “not only because
it delivers cost savings, but also because
it adds to the quality of the manufactured
component.
“Machining a part from metal bar can
disrupt and break its crystalline structure,
which could introduce weakness into the