How is a light bulb made out
How Light Bulbs Are Made
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the incandescent light bulb is a rather
simple device its base has two metal
contacts which connect to a metal
filament the electric currents electrons
collide with the atoms in the filament
making them vibrate this energy heats
the atoms to 4,000 degrees Fahrenheit at
which temperature they emit visible
light the light bulb Factory has two
production lines that eventually merge
one prepares the glass ball the other
makes what's called the mount the
electrical components that go inside it
at the start of the mount line a machine
cuts glass tubing into pieces of
specific lengths the cut tubes land on
what's called a glazing wheel that runs
them through a gas flame for about seven
seconds this heats the glass enough to
smooth the surface the glazed tubes now
enter what's called a flare making
machine which heats each tube until the
glass is malleable then stretches one
end into a flared shape
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the next machine loads to copper lead
wires into the flare end then it inserts
a thin glass cylinder called the exhaust
tube a trip through a series of
progressively hotter flames softens the
tubes a press then moves in to squash
them encasing the wires in glass at the
same time the machine makes a tiny hole
in the glass in between the wires this
is to later remove air from inside the
ball
it'll exit via the exhaust tube through
this hole next the machine separates the
lead wires and forms the ends into hooks
these fastened to the filament a thin
wire coil made of tungsten a type of
metal that holds up well to heat the
machine coats the lead wires in a liquid
form of another metal zirconium this
lengthens their lifespan by making them
more resistant to moisture inside the
ball like the tubes we've just seen the
bulbs are made of an inexpensive type of
glass called soda lime glass a machine
stamps the top of each bulb with the
voltage the wattage and the company logo
opaque light bulbs are simply clear
bulbs with an inside coating of
synthetic silica a white powder the
coating machine charges the bulbs to
30,000 volts combined with just the
right amount of heat this electrical
charge makes a thin layer of powder
cling to the glass a series of flames
evaporates moisture and bakes off any
impurities
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as the two production lines merge a bob
goes over each mount torches then fuse
the flare to end of the mount to the
neck of the ball arms move in and mold
the neck to fit inside the bulbs
aluminum base the next machine vacuums
out all the air and the ball and
replaces it with pressurized argon gas
this inert gas will resist heat buildup
helping the filament last longer after
bending the lead wires out of the way
torches melt and seal off the glass
exhaust tube locking the argon gas
inside the bulb would now be fully
functional if connected to an electric
current but it needs a base in order to
screw into the socket of a light fixture
the base is made of aluminum this
machine inserts one of the bulbs lead
wires through the middle and soldered it
in place it then spot-welds the other
wire to the side the result two base
contacts to line up with two socket
contacts
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on their way to packaging the bulbs
undergo what's called flash testing
repeated light ups using a higher
voltage each time this strengthens the
filaments inside making it less likely
to break during shipping
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