C1-C4 JAN/FEB 05 Resource

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					Non-Traditional Flow
                                                  Key to building 21st century John Deere tractors

Bill Grefe

       ill Tasch, manufacturing engineer with John Deere’s                     The Augusta plant now relies heavily on computerized
       Augusta, Ga., plant, located in nearby Grovetown,                  systems and advanced technologies to achieve high-quality
       has much to say about mastering flow manufactur-                   production of tractors. Plant expansion and diversion from
ing: “We opted for a flow manufacturing process to build                  traditional powered assembly line handling technologies is
our 5000 Series tractors; however, we needed it to operate                a 21st century approach to tractor assembly. The 5000
in a fully integrated and networked assembly system. We                   Series workforce is educated in flow manufacturing
chose ‘smart’ automated guided vehicles (AGVs) with                       methodologies and cross-trained for flexibility in a non-tra-
onboard computers that are precisely routed through                       ditional approach.
assembly steps and mesh with cross-trained operators                           Deere builds its 5000 Series of utility tractors on top
using ‘smart’ tools in workstations. The result is a ‘smart’              of wire-guided AGVs, a key part of a new, fully integrated
device network.”                                                          and networked, smart assembly line. The assembly line is
     There are nearly 3,500 steps in the assembly process                 more than a quarter of a mile long with 106 workstations.
for the 5000 Series tractors, but the entire job can be com-              The plant’s AGV fleet consists of 62 vehicles that serve as
pleted in less than four hours. To accomplish this, Deere is              the platforms upon which work-in-process tractors ride
breaking away from some assembly line traditions. For                     along the 443-m (1,452-ft) assembly line.
example, the tractors spend their first few hours riding on
AGVs through assembly.                                                    Speeding along a “racetrack”
                                                                              The assembly line is laid out much like a racetrack. It
Traditional company breaks tradition                                      has two spur or feeder lines for engine and transmission
    John Deere’s manufacturing traditions date back to                    assembly. Six AGVs work the engine line, and six more
1837 when blacksmith John Deere, developer of the first                   work the transmission line. The remaining 50 AGVs loop
commercial, self-cleaning steel plow, founded the firm.                   around the main racetrack line. The AGVs then mesh with

Riding around a quarter-mile racetrack

John Deere factory map: Automated guided vehicles transport John Deere utility tractors
around racetrack for the first quarter-mile of their existence. Starting from assembly of
engines and transmissions on AGVs in small loops (upper right), then continuing by AGVs        After a tractor’s engine and transmission are
on main track, work-in-process tractors move counterclockwise around and through a num-        ready for further assembly, they are lowered
ber of assembly steps. The final manufacturing process step is tire installation and tractor   onto an AGV by an overhead crane and hoist
unloading (lower right).                                                                       system.

January/February 2005
                                                                                                                 Resource                      7
cross-trained operators equipped                                                                     AGV details
with smart tools in workstations.                                                                         The Deere & Company’s fleet
     Meanwhile, Deere operations                                                                     of 62 automated guided vehicles
managers follow the progress on                                                                      centers around a single vehicle
computer monitors. Soon, assembly                                                                    design – a wire-guided AGV capa-
operators get their tractor build                                                                    ble of carrying 3.3-metric tons
instructions and quality control                                                                     (7,200-lb) gross weight. The AGV
information from the computerized                                                                    is outfitted with one of three cus-
system, which is easily accessible                                                                   tom fixtures, depending on
from touchscreen monitors posi-                                                                      whether it carries a tractor chassis,
tioned throughout the plant. System                                                                  engine, or transmission.
software uses radio frequency com-                                                                        The three-wheeled AGVs have
munication to directly interact with                                                                 a forward steer/drive wheel and
the AGVs’ onboard computers and                                                                      two fixed rear wheels. A 48-V
transceivers to precisely control and                                                                battery system powers separate
track AGV movements.                                                                                 steer and drive motors. An
     Full network implementation                                                                     onboard, microprocessor-based
ensures that the AGV will not move                                                                   system called TRACE 2000 con-
from a specific assembly station                                                                     trols each vehicle and communi-
until the work is complete and veri- Crane/hoist system moves tractor cab into place                 cates by radio signals with a base
                                         enabling it to be fastened to the rest of the tractor.
fied. The control system then                                                                        control unit. For most routing oper-
processes quality control parameters                                                                 ations at Deere, the vehicles travel
to guarantee acceptance. Also, the                                                                   at a speed of approximately 12 m
“smart” AGV only stops at assem-                                                                     (40 ft) per min.
bly stations where work is required                                                                       As an added safety measure,
on the specific tractor carried                                                                      the AGVs are equipped with a
aboard that AGV. The vehicle                                                                         mechanical bumper, infrared object
bypasses stations where no assem-                                                                    detection sensors, audible and
bly is needed.                                                                                       visual warning devices, a loss-of-
     Depending on the specific trac-                                                                 guidance braking function, emer-
tor under assembly and its options,                                                                  gency stop push buttons, and an
there is wide variability in the labor                                                               auto/manual key switch. If needed,
performed on each vehicle. For                                                                       the AGVs can be operated manu-
example, twice as many labor hours                                                                   ally by hand control devices,
can be expended on a high-option                                                                     enabling an operator to control
tractor as compared to the hours                                                                     speed, direction (forward or
spent on a basic model. Therefore,                                                                   reverse), and steering.
variable routing with smart AGVs is                                                                       The AGV system is wired-
important in juggling production         AGVs with onboard computers move tractors through           guided – which some would argue
scheduling.                              assembly steps. System software communicates with           creates inflexibility, but Tasch dis-
     Building a tractor requires that    AGV to stop only where work is required.                    agrees. “AGV routing is easy to
assembly operators perform the                                                                       modify. Simply cut a small groove
highest quality work with precision. Operators must per-               into the floor, lay more wire, fill in the cut with epoxy, and
form up to 70 critical steps involving the exact application           route the vehicles in a new direction. Thus, the handling
of the right amount of torque. Computerized, “smart” tools             and manufacturing system’s layout can be changed quickly
help operators complete these jobs and verify that the tool            and economically. That’s important because the utility trac-
itself has performed the job within the control limits. In             tor business is very dynamic. John Deere is always think-
some tasks, the tool even counts out the number of bolts               ing of a better way to give the customer the highest value
needed.                                                                products.” R
     To achieve this new level of manufacturing sophistica-
tion, Deere invested $23 million in the Augusta plant                  Bill Grefe is a director of project implementation for AGV
expansion, including the AGV system, smart tools,                      products, 8012 Tower Point Drive, Charlotte, NC 287777 USA;
106 workstations, and a new 17,466-m     2 (188,000-ft2)               704-845-1110, fax 704-845-111,
assembly facility. Flexibility is a key part of the new assem-
bly system, its handling devices, and even its workforce.

                                                                                                                   January/February 2005

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Description: our 5000 Series tractors; however, we needed it to operate ... John Deere factory map: Automated guided vehicles transport John Deere utility tractors ...