Smart craftmanship
At the Böllinger Höfe plant, part of the Four Rings’ site in Neckarsulm, Germany, craftsmanship is melded with smart factory technology to produce the fully electric Audi e-tron GT quattro.
Marrying the body, battery, electric motors, and suspension to create the e-tron GT quattro. An Audi technician positions the components under the body and pieces them together with the help of self-positioning screwdrivers.
Marrying the body, battery, electric motors, and suspension to create the e-tron GT quattro. An Audi technician positions the components under the body and pieces them together with the help of self-positioning screwdrivers.
As an employee carefully runs a gloved hand over the exterior paintwork of the fully electric e-tron GT quattro, her gaze follows the movement. The vehicle is illuminated with special lighting that allows Audi experts to spot even the smallest imperfections during the rigorous quality control process. In this case, everything is in order. Once an e-tron GT quattro has passed through the final quality check, it’s ready to leave the Böllinger Höfe premises. This final check is where the paintwork, joints, and gaps are put under the microscope one last time. If needed, fine adjustments are also done by hand at this stage. Before getting to this point, production models must first pass through numerous other stations. The Böllinger Höfe plant at the Audi site in Neckarsulm employs innovative, purpose-built technologies to manufacture the fully electric gran turismo.
Wolfgang Schanz, head of production at Audi Böllinger
Höfe, explains, “Producing the Audi e-tron GT quattro—and its body in
particular—is a highly automated process. Nevertheless, handiwork is part of
every assembly line cycle. The truth is that building a car still calls for
craftsmanship. Our colleagues perform this work with great attention to
detail.” Experience is another key factor. “We’ve carried over all the
handicraft skills built up in manufacturing the Audi R8. What’s more, the same
passion our employees invested in building the Audi R8 is now being poured into
the Audi e-tron GT quattro.” That’s because the production site for the fully
electric GT has been making the Audi R8 since 2014. “Right from the concept
phase, the Böllinger Höfe plant was designed as a small-series production
facility with innovative and flexible production processes,” says the
production manager. “That means the location offers ideal conditions for
manufacturing the Audi e-tron GT quattro.”
In order to accommodate vehicle production for both
models at one location, the flexible small-series facility was upgraded and
expanded. While retaining the strengths of the Neckarsulm-based Audi facility,
integrating the Audi e-tron GT quattro has entailed adding new areas of
expertise relating to electrification, automation and digitalization.
“Building a car still calls for craftsmanship. Our colleagues perform this work with great attention to detail.”
Wolfgang Schanz, head of production at Audi Böllinger Höfe
Paintwork quality control during the final finishing check.
European model shown. Specifications may vary.
Paintwork quality control during the final finishing check.
European model shown. Specifications may vary.
The two-way framer and correlation-free measuring
It goes without saying that striving to produce
high-quality, precision-engineered vehicles is a top priority at Böllinger
Höfe. Every process and every flick of the wrist is performed to this end. The
body shop is just one example of the perfectly symbiotic relationship between
craftsmanship and cutting-edge technology. A number of different joining
methods, ranging from resistance spot welding through screws to rivets and
bonding, come into play here. At the heart of the shop is a large clamping and
attachment system, known as the two-way framer.
“A framer is used to add large assembly groups to the
body, ultimately defining its geometry. Traditionally, two such framers, set up
as successive assembly lines, are necessary for body construction. At Böllinger
Höfe, we have succeeded in combining these steps into a single station that
each car body passes through twice. That’s why it has been dubbed the two-way
framer,” explains Christoph Steinbauer, head of the body shop. “On the first
pass, the inner side panels are attached; the outer ones on the second. Ten
robots with 32 tools are on the job, completing the steps required to join the
panels to the car body. They automatically switch tools between the two passes
and even during the work steps.”
The heart of the body shop—the two-way framer.
The heart of the body shop—the two-way framer.
Another new station is dedicated to correlation-free
measuring—an advance on previous inline measurement procedures. Two
robot-guided optical measuring heads check the exact dimensional accuracy of
the body at 400 different points. At each point, a blue stripe pattern is
simultaneously created and scanned before the robotic arm proceeds to the next
one. Room cameras detect and constantly compare the exact location of the
measuring heads. This method produces ultra-precise data that allows a rapid
response to even the smallest deviations. Following this process, the body
assembly line also includes two manual stations. Here, machines pass the baton
to humans who weld with great precision by hand. The employees at this station
benefit from the experience gained working on the Audi R8. Welders who have
spent years crafting the sports car with a V10 combustion engine (Fuel
consumption, combined*: 13.6–13 l/100km; CO₂ emissions, combined*: 311–297
g/km) entirely by hand are now well-equipped to work on the Audi e-tron GT
quattro.
Correlation-free measuring is performed on the assembly line with the utmost precision. More than 400 measuring points are checked. At each point, a blue stripe pattern is simultaneously created and scanned.
Correlation-free measuring is performed on the assembly line with the utmost precision. More than 400 measuring points are checked. At each point, a blue stripe pattern is simultaneously created and scanned.
After the body assembly line, the car-in-progress
moves on to the mounting stage. Trained body manufacturers mount the car’s
fenders, doors, engine hood, and tailgate. This step focuses on achieving
precise, uniform gap dimensions and high-quality surfaces—as even the smallest
errors here can result in deviations from the desired standard. This is why the
job not only calls for meticulous care and attention but is also best achieved
through a return to traditional craftsmanship. A trained carpenter with a keen
eye and feel for surfaces is a key part of the team. After the mounting stage
is completed, the bodies are ready to be painted.
Gap dimensions are checked by hand.
Gap dimensions are checked by hand.
Driverless transport vehicles and a newly installed electric overhead conveyor rail system
Freshly painted Audi e-tron GT quattro bodies are
briefly stored in a high bay in the basement of Böllinger Höfe. From there,
driverless transport vehicles (DTV) carry them to the assembly line on the
ground floor. They find their way with the help of a navigation map that
includes a digital representation of the surroundings. Two laser scanners at
the front and rear sound out the surroundings, ensuring that each DTV knows its
exact position at all times. Every day, the 20 smart transport vehicles cover a
total distance of around 23 kilometers. Not only do they deliver car bodies for
assembly, they also carry them during the first cycles and at the end of the
line.
At Böllinger Höfe, the Audi e-tron GT quattro and the
Audi R8 are manufactured on the same assembly line. To coordinate this joint
production process, the number of cycles has been increased from 16 to 36. The
logistics experts in charge of the processes carefully choreograph
everything—ensuring that the components for each model arrive in the right
place, at the right time, and in the right order. To ensure everything would
run smoothly, all assembly procedures were tested in advance using VR technology.
A key element of assembly is the “marriage.” This is
when the body of the Audi e-tron GT quattro is combined with the battery,
electric motors, and suspension. Resting on workpiece carriers, these major
technical modules are moved within millimeters of the correct position below
the body via a roller conveyor. With the help of self-positioning power
screwdrivers—and employees’ equally precise handiwork—parts are screwed
together.
DTV at work: Driverless transport vehicles have been moving car bodies through the assembly line at Böllinger Höfe since 2014.
DTV at work: Driverless transport vehicles have been moving car bodies through the assembly line at Böllinger Höfe since 2014.
“Planning of assembly sequences was done virtually for the most part.”
Wolfgang Schanz, head of production at Audi Böllinger Höfe
Human-robot cooperation and assembly aids from the 3D printer
Even though manual precision and dexterity are of
primary importance in assembly, robots help out in this area, too—for example,
when fitting the front and rear windscreens. Humans and machines collaborate on
this work step without safety barriers separating them. This is referred to as
human-robot cooperation (HRC). Workers first place the window onto a fixture
with automatically adjustable retainers. They then step aside while the robot
applies the adhesive. Next, the employees take over again and fit the window to
the body with extreme precision.
The 3D printer also makes life easier. At many
stations, specially designed assembly aids help the staff work more
ergonomically. Employees at the Böllinger Höfe facility who come up with good
ideas for improvement don’t have far to go to put them into action. They simply
take their proposal to the in-house 3D printing center. In collaboration with a
Berlin start-up, the Audi expert team has developed software that reduces the
design time for pre-assembly jigs and fixtures by 80 percent. Usually, all that’s
required is a sketch and the printed part is created in a matter of hours. This
marks yet another big step forward, as Wolfgang Schanz points out: “We have
established a lot of new methods, starting with the planning of assembly
sequences, which was done virtually for the most part. In the body shop, we
have introduced correlation-free measuring. And the assembly aids from the 3D
printer that serve as customized solutions for our employees are already
proving to be a great asset.”
By pairing extremely flexible, high-tech production
with artisanal workmanship, the Böllinger Höfe plant makes a compelling case
for enjoying the best of both worlds—craftsmanship and smart factory
technology.
European model shown. Specifications may vary.
European model shown. Specifications may vary.