Hydraulic and mechanical presses
offers two methods: forming in a conventional
hydraulic press (with a special hydroforming
unit) or a press designed solely for pressure
dome hydroforming.
“The conventional press is the right choice
when you need to be able to do normal
hydraulic pressing in the same press,” said Bo
Larsson, forming expert at AP&T. “However,
the special press is better suited to high pro-
duction volumes with many different products
Above:
traditional forming techniques) higher strength
requiring different tools.”
AP&T
at the same thickness and weight. There is
The low cost of tooling is another point in
hydraulic
very little or no scrap,” AP&T explained.
press for
its favour.
thixoforming
However, the thixoforming process must
“It becomes cheaper to manufacture many take place within a specific temperature range
different product variations, which is precisely (the ‘thixo window’) for it to work as intended.
what happens in niche production and this is If the material is too hot, it cannot be formed.
something that is growing strongly in many of If it is too cold, the desired properties cannot
our customers’ industries,” stated Larsson. be achieved, since the molecular structure of
Producing parts in a single operation allows the piece is determined by the temperature at
the quality to be kept more consistent (since which it is formed. For example, the strength
no imprints or marks are made on the parts). of an individual part can vary dramatically
The need for welding, grinding or other fin- if it is formed at the wrong temperature. The
ished work is also eliminated. ‘thixo window’ imposes special demands on
“In certain types of production, the finish- the forming equipment and process.
ing work is the most expensive operation but, “The material has to be at the right tempera-
with pressure dome hydroforming, this can be ture in the tool,” explained AP&T technical
avoided completely,” concluded Larsson. manager, Bengt Walkin. “We have to deal
AP&T has been successfully using hydrau- with the time factor and keep the material at
lic and electric servo technology for many the right temperature.”
years in hydroforming applications, presses
for forming hot materials and press lines Eye on the future
for producing heat exchangers, automation AP&T’s overall philosophy is simple, as Tord
systems and press lines. LOGOS, its new Anderson explains:
easy-to-use HMI (Human Machine Interface) “The gains that you make today, and in
software, was developed specifically for the the future, depend as much on how you use
sheet metal industry. and maintain your equipment as it does on
the equipment you choose. Availability and
Thixoforming research production rates are determined by how your
AP&T was also involved as a partner on an production equipment is designed and built,
EU project that tested the ‘thixoforming’ how the preventative service is set up and the
method on steel. The method is currently training that the equipment operators have
being used commercially to form aluminium received.
and is a technique in which the piece to be “For us at AP&T, it goes without saying that
formed is heated to a temperature just below we will support our customers with services
its melting point. The material then becomes that improve their production. This applies
soft without flowing and is thus very easy to to field service, preventative maintenance,
form. rebuilds, spare parts and training. We con-
“Given the right material composition, it is sider it our business to help our customers to
also possible to achieve (in comparison with achieve the best results.” ISMR
26 March/April 2007 International Sheet Metal Review
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