Finishing - November-December 2023

20 ROBOTS
Smart sensors
In many applications surface coating such as
electroplating is an important part of the
manufacturing process and if performed
manually, will require a considerable amount
of space and human resources. However, a
good example of the benefits of advanced
automation and robotics is the development
of an innovative robot cell which enables fully
automated electroplating and has proven to
be a big benefit to Swiss automation company
Roth Technik.
A three-way collaboration between the
customer, surface coating specialist Collini
based in Dubendorf, near Zurich, with
automation company Roth Technik and sensor
specialist BAUMER, has resulted in the
development of a fully automatic system for
plating racks. Minimal space was a key factor
for the customer which is why they were
looking for a space-saving solution that would
enable a fast and reliable way of hanging
small parts on racks in preparation for transfer
to the electroplating bath.
Marco Fuchs, Head of Product Engineering
at Collini explains, “Boxes containing small
metal parts were stacked in a narrow niche
with barely enough space to manoeuvre a
single pallet between the wall and the liquid
tanks. Behind this assembly are rows of tightly
packed electroplating tanks and this lack of
space was a key factor in why we were
looking for a space-saving solution that would
deliver a fast, reliable way of hanging small
parts on racks for the electroplating bath”. The
conventional method of loading the racks by
hand requires lots of space and human
resources because several racks need to be
loaded at the same time. Collini confirmed,
“This is why we wanted to switch to a new
automated coating system. However, this type
of system had yet to be created so we
embarked on a search for pioneering
companies that we could collaborate with to
take up the challenge”. The search resulted in
collaboration between Collini, automation
specialists Roth Technik, which in turn relies
on smart sensor solutions from Baumer.
Working together, the team began the
development of a fully automatic and compact
loading line. At the heart of the loading line
are 4 robots that automatically load parts onto
the empty hooks on the racks, with the
biggest challenge being that no two racks are
the same. The hook positions are not located
in exactly the same place on the welded racks
and some hooks may be bent or missing
entirely. Whilst this isn’t a problem for a
manual system, it is a big challenge for robots
that require precise positioning data.
Furthermore, the huge variety and high
throughput of parts presented other
challenges. So how did the ‘team’ solve the
problem of rack positioning accuracy, enabling
the robots to ‘learn’ the exact positions of the
hooks for each rack?
A simple, yet effective solution from
Baumer, the ultra-compact OXM200 profile
sensor proved to be a key component in the
efficacy of the system. Mounted on the robot
arm, the sensor detects the exact position of
each individual hook as it moves down the
rack and reports this data back to the robot
control. With the help of a camera, the robot
then picks up one part after the other from
the separating carousel and hangs it on a
hook. The robot uses the position coordinates
previously collected by the profile sensor to
finely adjust the position of the part and this
enables the profile sensor to guide the robot
precisely and quickly on the electroplating
rack.
Markus Roth, CEO of Roth Technik,
explains, “Whilst the process might sound
simple it requires the sensor to deliver an
outstanding performance, we had to install a
sensor that detects and precisely measures
very thin hooks, not just in 2-dimensional
space but in a 3-dimensional one too”. Initially,
the Roth Technik team tested various camerabased
systems and other laser-based scanners,
but eventually decided that the sensor was the
way to go. Markus confirmed, “In the end, we
chose the Baumer OXM200 profile sensor
because it was the best solution for our strict
requirements regarding accuracy, ultracompact
design and ability to detect objects”.
The OXM200 offers another major
advantage, thanks to powerful, integrated
measuring tools, the sensor outputs the
measured values for the X and Z coordinates
directly in mm, significantly reducing the
number of calculations in the control. This
resulted in less integration work on software
and enabled the project to be up and running
faster.
Also, thanks to Power over Ethernet (PoE) a
single cable is all that was needed to connect
the sensor to the control and supply it with
power, an important detail when it comes to
mounting the sensor on a mobile robot arm.
Further time savings are achieved by scanning
the hook positions only once when the rack is
inserted and as the control stores all the hook
positions, the racks don’t have to be scanned
each time. The result…two robot cells enable
a throughput of 15 million parts per year
using minimal space whilst eliminating the
issues associated with a manual system.
Finishing - November/December 2023