60
Tube Products International May 2013
Dawson Shanahan Ltd
– UK
This is because, during machining, bar stock grain is
interrupted, while cold-headed parts have a grain that follows
the configuration of the part. Cold forming therefore offers
improved mechanical properties with a greater strength-to-
weight ratio.
Cold forming is also allowing a greater number of parts to be
formed as single components, rather than a series of separate
ones. The potential to produce components of net, or near
net, shape has had a great impact on efficiency and economy,
as it reduces the need for many secondary operations.
The influence of cold forming continues as research and
development into the process shifts the balance away from
‘experience-based’ development towards computer-aided
research, ushering in a more analytical approach.
The potential to engineer high precision components by cold
forming aluminium is illustrated by a recent Dawson Shanahan
project that required a unique finish.
Cold-formed parts have surface finishes that mirror the
smooth condition and dimensions of the dies. Not only does
this somewhat ‘burnished’ condition often eliminate the
need for secondary finishing, it can also invest parts with the
capacity to preserve, for example, gases with zero leakage for
a number of years.
When Dawson Shanahan was commissioned to cold-form
an aluminium tube for the purpose of holding nitrogen gas,
the customer specified that a minimum pressure must be
maintained within the chamber for a period of two years. A
rubber seal contacting the chamber inner surface was created
to prevent gas loss. It was therefore critical that the chamber
surface was free from scratches, eliminating gas leak paths
that would lead to a loss of pressure.
Although the drawing specification required a 0.2Ra radial
surface requirement, the process produced results between
0.04 and 0.08Ra. The remarkable results achieved here by
cold forming only demonstrate the powerful potential of this
process method to meet the increasingly demanding needs of
many applications.
With over 60 years’ experience, Dawson Shanahan Ltd is
a global specialist in cold forming and machining of high
precision, customer-specified copper, aluminium, ferrous and
assembled components. The company offers a complete
solution, with everything from prototype to production
being designed and manufactured in-house, to reduce both
manufacturing lead time and costs.
The company’s products meet the demands of a wide range
of sectors including aerospace, automotive, electronics, laser,
medical, packaging, plasma, power distribution, telecoms and
welding.
Cold forming can provide a faster process option than die-casting or
machining from solid aluminium
Cold forming
offers a strong,
economical
alternative when
the complexity
offered by
hot forming is
unnecessary
