Jürgen Sielaff, U.I. Lapp GmbH
Highly specialized production with the
best levels of quality assurance -
this continues to be a unique feature of German industry. The new metal
processing center for industrial connectors operated by the Stuttgart-based
Lapp Group shows that the industrial production of components can be performed
at the highest level, even in the age of globalization and internal
competition.
Fully automated, reliable and made in Germany.
The Stuttgart-based Lapp Group boasts one of the most modern plants in
Europe for the mechanical processing of rectangular industrial connectors,
having operated its new metal processing center since mid-2013. Four handling
robots, two independent metal processing centers, a washing center and a fully
automatic riveting station with a loading and unloading station work around the
clock to produce around 580 industrial variants of the EPIC ® rectangular
and circular connectors from 54 unfurnished housings. The new production
facility not only achieves greater throughput, it can also manufacture all
variants in the product range in a flexible manner with short lead times. The
state-of-the-art plant was supplied and manufactured by German-based CHIRON
Werke GmbH.
The contact inserts of the rectangular connectors have been
manufactured in Germany for some time. This process was previously performed
manually, but was now automated and integrated into production so as to reduce delivery
times. This has resulted in highly automated production with a very high and
consistent level of quality. The process data is subject to continuous digital
monitoring – without any added costs. One of the additional aims of this
process integration was to enable new product variants to flow flexibly into
the processes and to engage in continuous adaptation of the product range in
line with the new requirements.
Highest levels of repeat
accuracy
Although quality control of the EPIC ® connectors was
previously performed manually, the entire process will now be performed fully
automatically. The robots use a measuring button to measure each individual
part and calculate any deviation and tolerance. They then immediately offset
the deviation and search for the zero point of the hole or identify parts in
which the tolerance deviation is too high, enabling the production facility to
achieve a very high level of repeat accuracy.
The focus then moves to the riveting station, another area featuring
fully automated processes. The bolt is individually moved, positioned and
riveted in accordance with the type and position. The riveting point is
corrected automatically as required. The riveting pressure is also monitored,
with the values being documented and stored. This provides assurance for the
operators that each part has been riveted. Conversely, in the case of manual
production, this can only be observed by the operators once production is output
by the machine. The advantages are obvious: the plant does not output any parts
that have been processed incorrectly and traceability is assured at all times.
Milling instead of cutting
A unique feature of the Lapp metal processing center is thread
manufacturing with the help of thread milling cutters – a system that was
developed in-house. As special aluminum coatings with outstanding hardness are
used for the EPIC ® housing in order to make it suitable for
application in all kinds of environments, this results in a fivefold to tenfold
reduction in the service life of standard drilling and threading tools.
However, thread milling cutters sustain virtually no measurable wear and
provide a range of additional advantages.
The thread
milling cutters enable spindle rotation speeds of up to 20,000 rpm to be
achieved. After processing, it is as though the thread has been polished – no
cleaning is required. The dimensional accuracy of the CHIRON precision
processing centers is in the m range. In
addition, various core hole and thread diameters with an identical gradient can
be manufactured using only one tool. A further advantage of PCD cutting, in
which polycrystalline diamond is used as a cutting material, is the low level
of component heating. Due to the quick processing, there is less of an increase
in the work piece temperature. This is more cost-effective as it enables
operation with minimum quantities of cooling lubricant. In this case, however,
the components are virtually warm to the touch upon exiting the device.
With the help
of the circular bore thread milling cutters and the
undercuts that
can be generated with them following the thread output, thread depths are
achieved in virtually the same way as with through-hole threads. As a result,
the rectangular connectors are compatible with conventional cable glands. The
fact that there are no longer any burrs in the thread outlet means that
deburring does not need to be performed. By implementing the thread milling
cutter in the new metal processing center, we were able to further increase the
service life of the tool.
New machinery concept
The aim of the
new machinery concept was to not leave anything to chance and to turn
weaknesses into strengths. "The combination of full automation and
digitised quality control enables the machine to attain a high level of repeat
accuracy and quality," enthuses Jürgen Sielaff, Production Manager for
mechanical processing at Lapp.
The biggest
challenge was to ensure that all the different variants of the EPIC ® rectangular
and circular connectors could be produced using a single machinery unit. The
adjustment of the various product variants using the zero point calculator was
a very complex procedure, but CHIRON was ultimately able to create a basic
device with the ability to accommodate all 54 connector variants. "In
succeeding in accommodating dozens of product variants across a very broad
range at a principal tension, we have created an incredibly flexible production
facility," explains Kristoffer Siegmann, Project Manager at
CHIRON.
This means
that the CHIRON production facility is also equipped for future demands, not
least thanks to the integrated cleaning device that exceeds current
requirements.
Control is now
performed by a central computer with an SAP connection that enables it to
immediately convert each customer order into a workshop order. In the event of
a complaint, every employee can instantly access all quality assurance data.
Staying competitive through
innovation
The example described here is a highly modern production plant that,
thanks to the combination of numerous innovations, an elaborate machinery
concept, fully automated production and highly qualified and highly trained
personnel, achieves the highest level of quality without generating costs any
higher than those involved in production in low-wage countries. This means that
the "made in Germany" manufacturing process remains competitive whilst
guaranteeing the highest levels of quality and dimensional accuracy.
