BPG 22: A fully-automated stamping press and test press all rolled into
one
The BPG 22 planetary gearbox developed by BRUDERER is a
world first, and something that stamping experts and tool-makers have been
waiting for – for a long time. It is an additional gearbox which will enable
fully-automated BRUDERER BSTA 510 stamping presses to be turned into test
machines for trying out new tools at the flick of a switch, and then afterwards
return to serial production – creating incredible added value for BRUDERER
customers!
In the past, stamping firms who created tools in-house had
only one solution for these two very different tasks – they had stamping presses
for actual production whilst having to carry out tool and stamping tests on a
separate machine, which would then as a rule stand idle until the next series of
tests, taking up valuable capital and production space.
Two becomes one
This new development from BRUDERER now offers a
practical alternative which provides the customer with real added value. A
planetary gearbox that is built into the shaft of the main motor of a
fully-automated stamping press enables test runs to be carried out, steered by
manual control, at the lowest stroke rate and at full press capacity. The values
that are produced can then be carried over exactly and used in the regular
production process. The advantages for customers are manifold: increased
efficiency, reduced costs, less space required, simple handling and more
flexible work processes. There is also a gain in terms of logistics, since tools
have to be transported less often.
The catalyst for this development was the servo technology which has become far more prevalent in recent years. While it is of little or no use for stamping at high stroke rates, which is one of
BRUDERER’s core competencies, it is however very suitable for slower processes
such as test stamping and try-out of tools. BRUDERER therefore decided to use
these very properties and adapt them to their high-performance fully-automated
stamping presses, and the result is the BPG 22. The aim was to combine two
machines in one – namely to take a regular high-performance fully-automated
stamping press and equip it at very low stroke rates with the capabilities of a
test press, which however do not have any influence on the (day-to-day)
functioning at higher stroke rates. A particular challenge was making the
strength and torque which are required for comprehensive test settings available
without the need for a significantly larger electric motor or having to changing
something significant to the basic principles of the tried and trusted BRUDERER
stamping press.
All different, all new
The project team found themselves confronted with quite a task. It was not merely a case of
developing a planetary gearbox – it had to be a three-level version. The basic
concept also called for it to be enclosed in a rotating casing, which posed a
further challenge. For project manager Pascal Hardmeier and the rest of his
team, there was a lot to learn, and while that did not make for an easy time of
things, it was certainly exciting and enriching work.
After the gearbox had been constructed mechanically, it was time to focus on the development of
the software, and this proved to be an exciting challenge for Herbert Högger,
Head of Control Engineering, and Sven Kächelin, in charge of the relevant
software development. This was a project where production at low speed was the
main priority as opposed to stamping, and this meant that everyone involved had
to approach the project from a completely different point of view. The work on
the BPG 22 also provided new insights of a more general nature, for example in
terms of process monitoring or the behaviour of BRUDERER fully-automated
stamping presses at low stroke rates. What Herbert Högger found most impressive
is the fact that the complete tonnage of the machine is literally in the hands
of the machine operator. Kächelin found the development of the manual control
particularly demanding. The requirement was for it to be able to work slowly but
at high strength and this ended up creating various new functionalities.
BRUDERER and the relevant suppliers were also involved on the hardware side, and
whereas »speed at all costs« used to be the watchword, now it is more a case of
»slower but stronger«. Consequently everybody involved in the BPG 22 project has
come to see the BRUDERER stamping press in a new, previously unseen light.
The result of this teamwork is a three-level planetary gearbox with a
ratio of approximately 1:19. The real heart of the BPG 22 is the software and
the manual control for the machine. The main functionalities include the
switching on and off of the gearbox in test mode, movement of the machine and
adjustment of the ram height all via manual control, as well as production at
low stroke rates. The data that is generated can then be transferred to the tool
data memory of the machine’s control system.
Everything in hand
The manual control enables the speed of the ram movement to be
adjusted to different levels. Maximum press capacity and the highest torque
levels can also be set and recorded. The machine operator can thus start the top
and bottom dead centre individually and move the ram to precisions of a
hundredth of a millimetre. The manual control can activate and control the
functions that are required for test mode. This for example means that the ram
and the upper part of the tool can be moved extremely slowly onto the lower
part, imitating a stamping process and testing move slowly forwards or backwards
in fixed geometrical increments or by regulated shifting using pre-set values.
Backwards movement can be implemented depending on the tool, and the permitted
press capacity can be changed where necessary. The operator can also specify
breakoff criteria for continuation or return stroke in the control system.
The manual control has several different indications. A multi-coloured
display shows the maximum and current press capacity, the press angle in degrees
and the distance of the ram from the lower dead centre. The control also enables
error messages from the machine to be displayed and acknowledged. It is linked
to the machine by a pluggable cable and can be used in front of or behind the
fully-automated stamping press, with the necessary cable connections built in on
both sides. If the manual control is not required, it can be stored in the wall
mounting that is delivered as standard or attached by means of a magnet to a
place of the operator’s choice around the machine.
Functional and practical
Safety was always foremost in mind during the
development of the BPG 22 since there are times when machine operators have to
use their hands inside the tooling or stamping area when in test mode. The BPG
22 was thus constructed according to the European 2006/42/EG machinery
guidelines, and is designed in such a way that test mode is automatically
switched off if there is any kind of power outage. If the stamping press is then
switched on again, it starts up in regular stamping mode. Test mode also needs
to be able to be activated manually if required. The machine is constantly
engaged when it is in test mode and the operator controls the stamping press
manually. When it is switched off, the gearbox then goes into neutral and the
machine is ready to resume its normal stamping functions.
The BPG 22 has no negative effects on the regular stamping process. On the BSTA 510 when it is
in stamping mode, the usual stroke rates of between 100 and approximately 1100
strokes per minute, depending on the machine size, are still possible. The BPG
22 also has no effect on the footprint of the machine – the planetary gearbox is
fitted in a way that the stamping press needs no extra floor space to
accommodate it, which is another advantage compared with previous solutions
which required separate equipment for test and production functions.
As far as company owner Adrian Bruderer and CEO Andreas Fischer are concerned, the
BPG 22 which is not only a world first but also an incredible idea, and they are
sure that this extension of functionality will be a real success. The gearbox
was developed in close cooperation with a number of key customers and will be
commercialised with a software stand, with any further enhancements worked out
with customers based on needs and practical experience.
The new 22 kW planetary gearbox is available for the BSTA 510 with three different die
mounting lengths of 950, 1100 and 1250 millimetres and will be delivered
exclusively with new machines. Other versions for the various different types of
BSTA will also be developed, depending on market requirements.