automation, robotics, assembly & machine build
Marshall Vehicle Engineering shows how effective welding robots can be with its first
implementation of robots in a production environment. Two robots mounted on a 24
metre overhead gantry are welding complex truck loading platforms in three and a half
hours - a reduction in 17 hours over manual welding times.
Marshall goes large
THE specialist vehicle and
shelter manufacturer Marshall
Vehicle Engineering (MVE) has
designed and developed cargo
beds, or loading platforms, for
the new MOD Support Vehicle
project. Working with prime
contractor MAN Truck and Bus,
the programme will see over
7,000 logistic vehicles supplied
up to 2014.
MVE General Manager Peter
Hardisty at MVE, explains: ‘This
is as near to volume production
that we have come to at Marshall,
and robots haven’t been used in
production to date. For the
manufacture of the load
platforms we moved to a new
dedicated site in Mildenhall and brought in
specialist skills to enable us to design and
implement a purpose built production facility.
The robot systems, together with a new
phosphating plant and paint facilities
represent a £5million investment in the site.’
He adds that the success of the facility depends
on everyone concerned understanding and
embracing the available technology.
An in depth tendering process, embracing
several of the UK’s leading robot suppliers,
illustrated to Marshall that the whole welding
process could be undertaken robotically and
with confidence. Based on its approach to the
requirement and proven capability Fanuc
Robotics was selected to supply the complete
welding system and provided detailed
simulations using its RoboGuide simulation
package. Off Line Programming (OLP) at the
early stage was carried out using solid models
of the fixtures that were imported into
Fanuc’s overall cell model.
The system comprises two Fanuc Robotics
ArcMate 120iL robots, each mounted
independently and hanging from a 24 metre
travel gantry. In addition each robot is
mounted on a supplementary gantry giving
two additional axes - one opposed to the 24
metre axis and one vertical axis. This
configuration of having each robot with
may 2009
The welding system comprises two robots, each mounted
independently and hanging from a 24 metre travel gantry.
three additional independent axes allows the
robots to operate with complete flexibility. It
provides the best possible positioning to
ensure maximum operating efficiency, and
ease of manual access for loading of parts to
the fixtures.
The Support Vehicle loading platforms are
built in three variants: 6 tonne, 9 tonne and 15
tonne; and respectively comprise 120, 140 and
160 parts each that require welding. After
loading the accurately laser-cut components
into the jig, the robots MIG weld the
components together. Simon Hale, Marshall’s
welding production manager, elaborates: ‘We
put a lot of heat into the platform during the
operation - over 2,000 welds are laid down in
the 3.5 hour cycle. Maintaining tolerance is
essential and if parts are not jigged correctly
we could lose up to 15mm through distortion;
therefore the sequence of programming that
we developed with Fanuc is very important
and to date it has produced good results.
‘The first platform programmed was the 6
tonne and Fanuc programmed this for us;
subsequent platforms - 9 and 15 tonne -
we’ve programmed ourselves. The platform
fixture is positioned on a head and tail stock
which allows the platform to rotate 80
degrees in either rotational direction. The use
of the auxiliary axis has made difficult
welding easy as all critical welds can be
presented in the correct orientation.’
In addition to the large welding
system, Fanuc Robotics also provided a
Fanuc Robotics System 100 stand-alone
weld cell. This system is used for
smaller sub assembly components.
Andy Caine, Marshall’s Operations
Manager for the Mildenhall site,
comments: ‘This operation is a
significant achievement for Marshall.
This is not a volume production
business and yet over a period of 18
months the business has acquired a
dedicated site, invested in capital
equipment and human resource, and
has achieved a very high level of
sustainable quality. Even more
impressive was the achievement of an
initial operational capability in just 7 months’.
Marshall Land Systems (MLS) is part
Marshall Group, a large (£750m) family
owned independent group of companies
working in the automotive, aerospace and
land systems markets. Predominantly based
in Cambridge, Marshall Group can trace its
history back to 1909. MLS specialises mainly
in defence vehicle and shelter design,
manufacture, integration and product
support. MLS has three major components, of
which MVE is one, that design and produce
shelters and specialist vehicles, manufacture
vehicle load beds and a specialist design
division which carries out UOR work, EOD,
EMI, EMC, safety cases and consultancy.
Fanuc Robotics UK provides integrated
robotic process solutions for manufacturing
industry. A wholly owned subsidiary of
Fanuc of Japan, it has been established in the
UK since 1982. The parent company was
established in 1972 and employs over 2000
people world-wide. Based at the foot of Mt
Fuji near Lake Yamanaka its factory uses over
1000 of its own robots to support the
production of over 24,000 robots per annum;
global installed base of Fanuc robots is over
200,000.
www.fruk.co.uk
www.marshall-ls.com
MWP
63
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