hydraulik - HANSA-FLEX Hydraulics Canada Inc.

HYDRAULIKPRESSE
BVV – BOCHUMER VEREIN VERKEHRSTECHNIK
Precision wheels from the coalfields
Baptism of fire
Keeping things rolling
Various production systems were not routinely
overhauled until the end of the year. Entire production
units underwent a thorough overhaul. This
extensive work calls for careful planning every time
- after all, the manufacturing equipment needs to
go back into production on schedule without any
delay.
High-speed trains race along the track at 250 km an
hour. This puts wheels under enormous strain, calling
for maximum reliability. The precision wheels manufactured
by Bochumer Verein Verkehrstechnik (BVV)
for the German and international railway companies
are designed to provide top levels of accuracy and reliability.
This means they are correspondingly dear to
manufacture.
In the historic-looking factory buildings based in
the heart of the coalmining town of Bochum 580
employees use high-tech machinery to produce
some 120,000 locomotive wheels in various configurations,
operating round the clock, seven days
a week. This medium-sized company belonging to
the Georgsmarienhütte Group of Companies has
operated in the steel casting sector since 1841.
Such precision wheels literally go through a baptism
of fire as the special steel, which is alloyed to cope
with the stresses imposed on locomotive wheels, is
heated to a temperature of around 1300 degrees C.
The red-hot block of steel is forged into shape using
a special press with a force of 6,000 t.
Locomotive wheels are made of a single piece of
metal for safety reasons as weld seams are unable
to meet the necessary standards. The red-hot blank
for the wheel, which has been previously sawn into
shape, is processed using a forging press and then
calibrated in subsequent work steps on a 2,000
t press. Next the outer contours of the wheel are
checked by measurement with a laser.
Next comes fine machining, a challenging task that
is performed by robots and high-performance precision
machines at CNC machining centres. At the
end of the production process are wheels which will
run 100% true, down to a hundredth of a millimetre,
and are designed to ensure reliable operation in
heavy-duty rail traffic whatever the weather.
In the planning phase the Repairs, Maintenance
and Service department first of all works out the
level of reconditioning and/or replacement work
required for each machine. This phase also identifies
any leakage. The behaviour of the machines during
production provides pointers about measures that
might be necessary. Such information allows the
company to draw up exact plans for the overhaul
and order all spare parts needed in good time. Surprises
may however still be in store. When panelling
is removed from the machinery, this may reveal
damage and defects that were previously hidden,
such as a leaking hydraulic cylinder or even a unit
with reduced capacity levels. If this is the case, specialists
and technicians from external companies
will have to be called in to help the maintenance
team with the overhaul. The only thing that is certain
in this process is the end date for the service:
that’s definite!
To make sure its machinery and systems are always
ready for operation, BVV involves the service staff
of the machine manufacturers not only in the overhaul
but also in the servicing process. They are of
course familiar with all technical issues relating to
their machines. Here HANSA-FLEX’s Bochum branch
acts as the specialist for hydraulic hose lines and
repair of the line engineering as a high level of hydraulics
is involved in the forging and rolling mills.
HANSA-FLEX is also increasingly accepting work
from plant manufacturers when it is a question of
line engineering and services. All services involving
hydraulics are coordinated by Christoph Bergfried
from the Bochum branch - and not just when overhauling
is underway.
16
HYDRAULIKPRESSE
ISSUE APRIL 2008