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Your
senses are assailed by the sound of dozens of dies slamming together
with up to 500 tons of force. The smell of hot oil on metal fills
your nostrils. Because of the noise, heavy equipment and sharp steel
edges, team members wear more protective equipment here than in any
other area of the plant: steel-toed shoes, long sleeves and pants,
gloves, safety glasses and ear plugs.
This is Stamping, where each weekday nearly one million pounds of
steel are trucked in and transformed into 121 different parts for
the Tacoma, Corolla and Vibe.
Other NUMMI employees usually associate two things with Stamping –
long hours and good pay. Team members typically work up to 50 hours
a week to meet the demand for parts, some of which are shipped to
Canada.
The process begins with the arrival of large steel coils, which come
in various widths and thicknesses and weigh as much as 48,500 pounds
(more than 24 tons) each.
Team members check the specifications, brush off any debris, and then
feed the ribbon of steel into a machine that washes, brushes and rinses
the metal. From there it passes through 11 straightener rollers that
flatten it.
Next, the roll enters one of two blanking parts presses, where various
dies – working like cookie cutters – cut the metal into
two-dimensional pieces. These pieces travel on a conveyor belt and
are lifted by a magnet, stacked into piles, and then placed on pallets
for transport to the production press lines.
NUMMI has nine such lines. Each contains three or four dies that work
together to form the two-dimensional steel plates into three-dimensional
parts. A line produces an average of seven parts per minute. The process
is highly automated, as robots or mechanical transfer devices are
used to move the pieces from one die to the next. Team members are
mostly responsible for running, monitoring and servicing equipment
and stacking finished parts onto customized racks.
Dies for the blanking and stamping presses weigh up to 100,000 pounds
each. NUMMI uses about 250 dies in Stamping to produce parts for current
models, plus another 90 for models that are no longer in production.
Most of the dies can be used in more than one stamping line, so if
there’s a problem with one line, the work can be shifted to another.
But we don’t stock replacements for the dies themselves - which
cost as much as $1 million per set - so any serious damage can halt
parts production until the die is repaired or replaced. Since NUMMI
normally only keeps enough parts in stock to last about five hours,
a problem that can’t be corrected quickly can potentially shut
down the assembly line.
The presses and coils are so heavy and the pressure used to stamp
the pieces is so great, that the floors in Stamping had to be specially
engineered to withstand the incredible force. Under the die areas
the floor is more than four feet thick and used 90,000 cubic yards
of cement. That’s the equivalent of a road 10 feet wide and one
foot deep from NUMMI to San Francisco!
A huge part of Stamping lies unseen beneath the plant floor. In this
thundering underground labyrinth are tanks of oil and the hydraulic
equipment that pressurizes the machines. This is also where metal
trimmings from the blanking and stamping operations drop onto conveyor
belts underneath the presses. Some 200 tons of scrap metal a day feed
into a main conveyor that transports them to a baling operation. Pieces
of various shapes and sizes are collected and then crushed in a kind
of giant trash compactor. A huge magnet loads the resulting 350-pound
blocks onto trucks. They’re sold to a metal recycling company
where they are melted down and used to make pipes, beams, plates and
other steel products.
NUMMI constructed a new $47-million stamping line in 2000. This state-of-the-art
project produces parts twice as fast as older lines. It also stamps
two parts (like left and right doors) simultaneously and combines
the Corolla body side and quarter panels into a single part, saving
still more time and money. |
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