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SPRING HILL PLANT
MODIFICATIONS HELP SATURN BUILD QUALITY INTO NEW VUE
 The
VUE is assembled at Saturn's manufacturing complex
in Spring Hill, Tenn. Originally built during the
latter half of the 1980s, the facility was expanded
in order to manufacture the VUE and a new engine module.
"Saturn has implemented a host of improvements to
our Spring Hill operations," said Annette Clayton,
Saturn president. "The modifications cover new equipment
and tooling for the Saturn VUE and next-generation
small cars, a refurbishment of the paint shop, and
structural changes so that both cars and trucks can
be manufactured in the same plant. The changes also
include building a 445,000-square-foot addition to
the Spring Hill Powertrain facility to produce GM's
global 4-cylinder engine module - one of the engines
that will be used on the Saturn VUE."
As part of the changes, General Assembly areas were
revamped to form two new lines, accommodating both
car and truck manufacturing, and the Body Shop was
converted to a flexible system with the ability to
build cars and trucks. The Paint Shop was modified
to increase the output of painted polymer panels,
allowing VUE and S-Series panels to be painted in
the same paint run. The Paint Shop was also updated
to allow the use of electrostatically applied materials
and a broader formulation of paints.
"The recent plant improvements made for the VUE
have modernized our facility, which will ensure the
high level of quality Saturn customers expect," said
Dennis Dougherty, Saturn's vice president of manufacturing.
"We are very excited to build this product," said
Jeep Williams, UAW Local 1853 Chairman. "Our workforce
has gone through hundreds of hours of training to
prepare for VUE production."
Progressive manufacturing techniques
The Spring Hill facility uses a number of progressive
manufacturing techniques. One example is the skillet
conveyor system. The skillet conveyor system exemplifies
Saturn's commitment to synergy between people, process
and technology.
In addition to conventional conveyors, General Assembly
uses "skillets" - large, moving platforms that support
both the vehicle and the manufacturing team performing
assembly operations. Team members can elevate the
vehicle to a comfortable height. The skillet system
is more ergonomically friendly, helping to reduce
fatigue and improve quality - in contrast with a conventional
system that requires people to walk along a fixed
floor adjacent to a moving conveyor.
As with many of GM's manufacturing facilities, Spring
Hill also incorporates doors-off general assembly.
Doors are removed from the body in General Assembly,
making it more ergonomically friendly for team members
to perform interior assembly work on the vehicle.
Door systems are built up in a separate area, and
meet the vehicle in sequence after interior components
have been installed.
Unlike conventional assembly plants, there's never
a need to paint a fully finished body assembly at
Spring Hill. Instead, the space frame is treated with
normal rust proofing and coating operations but no
body-color finishing. The steel roof, hood, and liftgate,
and polymer exterior panels are painted as a complete
set on moving fixtures conveyed through the paint
process. This helps provide efficient handling and
a high-quality exterior finish.
Spring Hill uses a just-in-time manufacturing system.
Subassemblies and other components arrive at the plant
only 90 minutes before they are installed on a vehicle.
This minimizes the investment necessary for in-plant
inventory and storage space. If a quality problem
is discovered, the significantly shorter supply chain
helps hasten a resolution.
The Spring Hill plant has adopted the Andon System
to allow team members to ensure quality build in station.
If an operator pulls an Andon Cord, assistance is
immediately deployed to resolve the problem.
The plant also will use a number of error-proofing
methods to monitor issues such as proper fastener
torque and option content. For example, software in
"smart tools" allows these tools to know which particular
vehicle they are being used on, thus preventing a
vehicle from advancing down the line with the incorrect
amount of torque applied to the fasteners. Another
example of error proofing occurs when a team member
reaches in a rack for a part, such as badging or cladding.
The operator's hand breaks a beam of light, and a
computer determines if the right selection was made.
If the wrong part is selected, an error message goes
off.
General Assembly
To minimize the disruption of S-Series manufacturing
operations and stretch investment costs, the General
Assembly area was converted from a one-line to a two-line
operation using existing conveyor systems and skillet
lines. To prepare for the VUE, the S-Series line was
condensed to use only 70 percent of the original floor
space, thereby clearing room for the second assembly
line. Less plant space is needed to manufacture the
VUE because several notable components and sub-assemblies
are built off-line or sourced from external suppliers.
Wheels and tires arrive mounted, inflated, balanced,
and ready for installation. Finished steel parts arrive
at the Body Shop or Paint Shop on a just-in-time basis.
A major cockpit assembly - consisting of the instrument
panel, internal reinforcements, the HVAC system, the
steering column, pedal assemblies and the brake booster
- is built up off-line at the Spring Hill facility
and delivered in sequence, ready for installation.
Body Shop
The Spring Hill Body Shop now has the flexibility
to produce intermixed cars and trucks even though
the size and makeup of the finished products are significantly
different. The new flexible approach will enable Saturn
to respond faster to market trends by varying the
product mix.
The Spring Hill plant is one of the first GM installations
to adopt the flexible Body Shop, a hallmark of the
GM global manufacturing strategy that is currently
being implemented. "We have world-class dimensional
control in our Body Shop, said Clayton. "This results
in excellent interior and exterior fits."
The ability to mix body styles is facilitated by
indexing tool trays on the main lines. Computers automatically
load in the appropriate software so robots and weld
guns are properly configured to handle the required
operations for either a car or truck. Some framing
stations are common to both products, while others
are unique to either the S-Series or the VUE.
The Body Shop in Spring Hill also features a new
metal stamping press. Known as the AA (double A) press,
the machine is the largest of its kind used in the
auto industry today. This massive press, which stretches
300 feet in length, weighs 13 million pounds and exerts
6,000 tons of pressure to stamp components, is housed
in an all-new 100,000 square-foot addition to the
Saturn Body Systems plant. This addition was constructed
specifically to house the press. The AA Press makes
hoods, door panels, floor pans, and other metal parts
for the VUE, as well as future Saturn products.
Paint Shop
Saturn's Spring Hill plant was among the first in
the U.S. auto industry to use more environmentally-friendly
water-borne primer and base coats. Using water instead
of solvents as the pigment carrier vastly reduces
the quantity of volatile organic compounds vented
to the atmosphere.
The introduction of the VUE brings an even more advanced
paint process with the use of an electrostatic charge
to help draw positively charged paint materials to
a negatively charged body panel. A common process
in painting steel, the use of an electrostatic charge
with polymer improves both quality and efficiency
by enabling more even coverage, particularly in less
accessible areas, while also reducing overspray.
All parts are finished with one new flexible clear-coat
paint system eliminating the need for one clear coat
for fascias and another for the semi-rigid (steel
and molded polymer) panels. In addition to improved
processing, the new clear-coat system provides added
scratch-and-mar resistance.
Engineering and process advancement
VUE engineers used state-of-the-art processes to design
the vehicle for efficient production. Unigraphics
solid modeling provided a critical tool in designing
many body-related components for manufacturing, including
door openings, interior surfaces, seats and underhood
hardware.
While Unigraphics has been used in the chassis area
for years, the VUE is one of the first products to
extend that capability into body areas. Because the
full vehicle exists as a detailed math model, it is
easier to implement engineering revisions; when a
single line changes, all related components are readily
updated. By catching problem areas early in the process,
changes could be implemented before making prototype
parts that are expensive and time-consuming to produce.
Using math modeling, VUE engineers simulated assembly
practices in order to quickly and inexpensively validate
procedures, check clearances and resolve ergonomic
issues. For example, engineers used Unigraphics modeling
to study how efficiently body and chassis points would
merge, and to find the best ways to load the large
cockpit module through a door opening.
Because the polymer panels used on the new VUE are
significantly larger than those found on current passenger
cars, improvements for injection molding processes
were necessary. Instead of injecting material into
the mold at a single point, it is filled concurrently
at two locations. This reduces the distance the material
has to travel through the mold and improves the quality
and consistency of the finished part.
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