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Ford's revolutionary concept of the assembly line to make cars
included a rope which pulled a line of chassis along a track, at
which stood fifty workers, each fixing their own allotted part to
each chassis as it moved by. Assembly time for a chassis dropped from
twelve to one and a half hours. In less than ten years, the price of
a Model T dropped from $850 to $250. Ford sold 1.8 million Model T
cars. In 1951, Ford led the way in using automatic equipment to
produce engine blocks.
The urge to save labor has continued to inspire new developments,
with robots replacing workers, cutting out tedious tasks and
guaranteeing greater accuracy. On the Fiat Uno, 30 of the 2700 welds
are done by hand. Only specialized crafts, such as electrical wiring,
now remain in human hands.
In a typical car assembly in the 1980s, the first stage was sheet
steel arriving at the press shop. In areas as large as three football
stadiums, robot cranes supplied rolled sheets of steel to giant
stamping machines, which cut the pieces of metal to make up the car
body. Then robots built the underbody or floorpan, making numerous
welds and creating a complex shape with spaces for wheel arches, boot
wells and spare wheels.
In the next stage, large jigs positioned the body sides and roof to
be welded into place automatically. In the meantime, the doors had
been made on nearby assembly lines in a process that involved several
different pressings to create an outer skin clinched over an inner
frame. Finally, lasers checked every car body for the smallest flaw,
distortion or irregularity.
The car, now largely assembled, was cleaned in a degreasing tank,
rinsed and coated with phosphate to make it more receptive to the
paint. After further rinses, base primer coat was applied, in several
layers. These primer coats were sprayed on electrostatically, using
an electric field to attract the paint. The last layers, usually
three, were glossy acrylic paint. The paintwork on most mass-produced
cars is 0.1mm thick; although on a Rolls-Royce, there are 22 layers
of paint, giving a thickness of 0.2mm. Special wax was then applied
to protect against water, snow, grit and salt. This was injected into
hollow sections such as pillars and sills.
The next stage, the trim, fitted out the interior. The car was wired
with its electrical system. Robots fitted underfelt, carpets, seats
and other fittings. Windscreen and some other windows were often
glued to the car to make a better fit and reduce wind resistance and
noise. Robots applied the glue to the edge of the glass and then put
it in place on the car with sucker grips.
Finally, the car was hoisted up, and a jacking system brought the
engine, complete with clutch and gearbox, into position. The fuel
tank was mounted at the rear end of the car. Next came suspension,
steering, radiator and battery, and then the wheels and tires. When
water, antifreeze, oil and gasoline were added, the car was ready to
run. Inspectors examined it at the gate before its final road tests.
When the car was given it final checks, it was ready for the dealer.
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