Leicht + Müller - E. Bruderer Maschinenfabrik AG

STANZEN
Productivity through optimised
tools and punching presses
The current atmosphere in press shops is really not as gloomy as one might think, despite only
"moderate" demand for production. Leicht + Mueller's motto, however, is "invest now if you want
to be part of the next economic boom". Logically, the company is not only investing money but
also know-how. With highly productive tools and the right BRUDERER high performance
punching presses, Leicht + Mueller is well equipped for the forthcoming upturn.
Highly productive tool for production of
13600 blade contacts with needle eye per
minute at a speed of 1700 spm and eight
blade contacts per stroke.
"Productivity can be achieved in two
ways", says Klaus Mueller of Leicht +
Mueller (L+M) Punching Technology in
Remchingen, Germany, commenting on
the developments in high precision tool
making: With high profile, high
performance punching presses that run at
16 02.2002 Blech Rohre Profile
maximise the performance potential of the
punching presses. If companies can
optimise both, the result is highly
productive solutions.
This is the case with the 8-impression tool
designed and built by L+M to
manufacture pins,

which are used to connect electronic
components to printed circuit boards.
Used on a BRUDERER high performance
punching press at a speed of 1700 strokes,
the L+M tool can produce up to 13600
parts per minute.
And these parts aren't that simple to
make: The contact plugs are, in fact,
components with a profile of just 0.5mm2
into which a so-called "needle eye" is
inserted. This slit creates a springy area in
the pin that compensates the bore
tolerances when the pins are pressed into
the PCB.
The stamping alone of such a pin is technologically
complex because the usual one-sided cut used in
conventional stamping techniques turns the pin.
The L+M tool makes straight pins using a unique
all-round cutting technique developed in
Remchingen: Both sides are stamped
simultaneously whereby the pusher is on the
bottom and the die plate on the top. The scrap
remains connected to the strip and is then stamped
out at a later stage.
Klaus Mueller does not, however, reveal
too may more secrets about the tool that
produces eight components per stroke,
except that the trick lies in the slotted
punch or inside profile.
"When working with quantities in excess
of 1 million parts, you are looking at a
totally different dimension of
toolmaking", he explains his reserve. Each
high precision toolmaker develops his
own techniques and toolmaking
philosophy that has to prove itself to
customers and the metal-working industry.
The rest is know-how, a kind of payment
in kind.
Fact, rather than a trade secret is, however,
that at 1700 spm, accelerations of 35g
were measured on the top of the die,
making a light-weight and compact design
absolutely imperative. That is why L+M

STANZEN
uses modular tools, without exception,
whose individual modules are springmounted
to the tool frame. This not only
has the advantage of less moving masses,
but each individual module can be
maintained or modified without the
engineer having to remove the entire tool
from the press.
For Klaus Mueller the user-friendly
maintenance and operation of tools is
today just as much a part of precision
toolmaking as the extremely service life of
up to 20 million strokes and long tool life
of several 100 million parts.
Leicht + Müller
The toolmaking company Leicht + Mueller
was founded in 1985 by Heinz Leicht and
Klaus Mueller. With its 40 employees, the
company has an annual turnover of 5-6
million EURO that is divided between the
manufacture of high performance
punching tools and stamped parts
production.
The development of the tool producing 8
components per stroke is supported by an
order volume of 500 million parts/year.
Even at speeds enabling an output of
13600 parts/minute, the press needs to run
612 hours continuously.
Presses to match the tools
The tool is one thing needed to achieve
this production performance, the press is
the other. When asked what toolmakers
regard as the single most important
demand made on a press, Heinz Leicht,
co-director of the Remchinger company,
answers: "Every toolmaker knows that no
tool can guide a ram". That is why high
performance punching presses must be
extremely accurate and rigid. Ram tilts on
the cutting level or frame spring of the
press frame have a direct impact on the
durability of high performance punching
tools, and on the overall punching
operation.
Furthermore, the first and last stroke of
any sequence is also of importance,
18 02.2002 Blech Rohre Profile
The employees of L+M are
enthusiastic about the on
PC-technology based
B-Control.
BRUDERER high performance
automatic punching presses
at L+M in Remchingen.
because of possible eccentric loads. Plus
the costs for a highly productive tool are
so high at 750000 EURO that faults in the
production process leading to tool damage
must be avoided at any price.
Leicht + Mueller was founded in 1985 and
since then has always used BRUDERER
punching presses. They are now the proud
owners of no less than seven BRUDERER
presses with press forces between 25 and
80t, because it is often the case that after
having a tool built, customers also ask the
company to produce the parts with the
new tool. About 50% of the annual
turnover at Leicht + Mueller is generated
by punching production. Try-out and
High performance production -
blade contacts with needle eye.

production runs are carried out on the
same presses, so that all tools can be run
in straight away under production
conditions.
That is another reason why the two entrepreneurs
have remained loyal to one single brand, because
they know from daily experience that e.g. the tools
that run on the 50t press can be interchanged as
often as required and run on all four presses. Over
the 17 years that BRUDERER presses have been
used in Remchingen, there were never any
problems with downtime, which, according to
Klaus Mueller, is essential when you are working
together with the automobile industry.
The 8-impression tool is currently running on a
BSTA 300-85 BF which, with a press force of 300
kN reaches speeds of up to 1800 spm. The system
is automated with coilers from Peripherie Anlagen
GmbH. The part control is carried out by a camera
and image processing system from Vester
Electronics that has been specially designed to
measure at high speeds.
Blech Rohre Profile 02.2002 19

STANZEN
Future prospects - looking good!
Even though some of the punching presses
were not up and running during our visit
to Leicht + Mueller, the future prospects of
BRUDERER punching presses
The BRUDERER punching presses are
driven by a transverse shaft. A perfected
articulated lever system with mass
counterbalancing ensures an optimal
distribution of power so that only approx.
60% of the punching force is transferred
to the main shaft. The drive bearings are
serviced by a central oil lubrication and
cooling system, thermally neutral sliding
guides compensate material expansions
on the ram due to temperature fluctuations
and ram guides are situated on the
strip inlet level - three characteristics
typical of BRUDERER punching presses.
The latter minimises the lever of the
punching forces on the ram and effectively
prevents ram tilting.
both entrepreneurs sounded optimistic. In
Remchingen they are almost certain that
there will be an economic upturn - and
only those who offer innovative and
productive solutions will profit from this.
L+M has already proved the innovation
potential on many occasions with its tool
Drive model in the conference
room at L+M. The
lever system with mass
counterbalancing optimizes
the load distribution
on the BRUDERER
punching press.
20 02.2002 Blech Rohre Profile
Modular tools facilitate
the maintenance and
operation and reduce
the moving masses.
producing 8 components in one stroke. It
was also the very same Remchinger
company that in 1996 introduced the
production of 2-part contacts from 2 strips
including assembly and laser welding in
one single tool. This tool was also used on
a BRUDERER punching press.
Leicht + Müller
Stanztechnik GmbH & Co.KG
Daimlerstraße 14
D-75196 Remchingen
Tel.:+49 7232 3686-0
Fax: +49 7232 3686-36
E-Mail: info@leicht-mueller.de
Internet: www.leicht-und-mueller.de
Bruderer AG Stanzautomaten
Egnacherstraße 44
CH-9320 Frasnacht
Tel.:+41 71 4477-500
Fax: +41 71 4477-780
E-Mail: info@ch.bruderer-presses.com
Internet: www.bruderer-presses.com
In order to prevent
ram tilting the ram
guides are situated
on the strip level.