How It's Made (2001–…): Season 8, Episode 4 - Deep Cycle Batteries/Tins/Optical Lenses - full transcript
Narrator:
TODAY ON "HOW IT'S MADE"...
DEEP-CYCLE BATTERIES...
...TINS...
...AND OPTICAL LENSES.
A DEEP-CYCLE BATTERY IS WHAT
YOU FIND IN SUCH VEHICLES
AS TRAINS, BOATS, R.V.s,
AND FORKLIFT TRUCKS.
WHEREAS A CAR BATTERY PROVIDES
A QUICK SURGE OF CURRENT
TO START THE ENGINE,
A DEEP-CYCLE BATTERY PROVIDES
A STEADY AMOUNT OF CURRENT
OVER A LONG PERIOD OF TIME.
DEEP-CYCLE BATTERIES RANGE
FROM 2 TO 48 VOLTS.
THEIR POWER IS GENERATED
BY CELLS,
A GROUP OF LEAD PLATES COATED
IN LEAD OXIDE AND ACID.
THIS CASTING MACHINE
PRODUCES LEAD GRIDS
THAT WILL BECOME THE PLATES
IN THE POWER CELLS.
THE MACHINE POURS MOLTEN LEAD
INTO GRID-SHAPED MOLDS.
WATER CIRCULATING
THROUGH THE MOLD
HARDENS THE METAL
IN JUST FIVE SECONDS.
THE MACHINE CASTS
TWO TYPES OF GRIDS --
NEGATIVES AND POSITIVES.
THE NEXT MACHINE COATS THE GRIDS
WITH A CHEMICAL PASTE
THAT CONTAINS
LEAD OXIDE AND ACID.
THE POSITIVES
GET ONE PASTE FORMULATION.
THE NEGATIVES, A DIFFERENT ONE.
THE GRIDS ARE NOW CALLED PLATES.
WORKERS STACK THEM IN CASES,
ALTERNATING
POSITIVE AND NEGATIVE,
THEN DROP THEM IN TANKS
OF SULFURIC ACID TO CHARGE.
THE LEAD OXIDE AND ACID
IN THE PASTE STORE THE POWER.
AFTER CHARGING
FOR 24 TO 72 HOURS,
DEPENDING ON THE MODEL,
THE PLATES GO INTO A MACHINE
THAT WASHES THEM THREE TIMES
TO REMOVE ACID RESIDUE,
WHICH, IF LEFT,
WOULD CORRODE THE METAL.
THE CHARGING PROCESS
BLACKENS THE PLATES,
WHICH ARE NOW CALLED
DRY-CHARGE PLATES.
A MACHINE WRAPS EACH POSITIVE
IN GLASS-STRAND MATTING,
AN INSULATION MATERIAL
SIMILAR TO FIBERGLASS,
THEN IN A PLASTIC ENVELOPE.
THESE COVERINGS PROTECT
THE PLATES FROM SHORT CIRCUITS.
WORKERS STACK
THE PLATES AGAIN --
POSITIVE, NEGATIVE,
POSITIVE, NEGATIVE.
THIS TIME, THOUGH, EACH STACK
CONTAINS A SPECIFIC NUMBER --
FROM 5 TO 33 PLATES,
DEPENDING ON THE BATTERY MODEL.
EACH STACK WILL BECOME ONE CELL.
A CELL PROVIDES
2 VOLTS OF ELECTRICITY.
EACH PLATE HAS A TAB.
A ROBOTIC MACHINE CLEANS
THE TABS WITH A WIRE BRUSH
AND A CHEMICAL SOLUTION
CALLED FLUX.
THEN IT DIPS THE TABS
IN MOLTEN TIN.
THIS TIN COATING
WILL IMPROVE THE BOND
WHEN THEY SOLDER
THE TABS TOGETHER.
THE ROBOT WIPES THE TABS
ON A FLUX-IMBUED SPONGE
TO CLEAN THEIR SURFACE
ONCE AGAIN...
...THEN DROPS THE CELLS INTO
A MOLD CONTAINING MOLTEN LEAD.
THIS SOLDERS THE TABS TOGETHER,
BONDING THE PLATES
WITHIN EACH CELL.
THE PROCESS CASTS TWO LEAD POSTS
ON THE CELL'S POSITIVE SIDE
AND TWO ON ITS NEGATIVE SIDE.
THESE POSTS
WILL CONNECT THE CELLS
AND BUILD THE REQUIRED VOLTAGE.
NEXT, EACH CELL GOES
INTO A POLYPROPYLENE CASING
CALLED A JAR.
THEY TEST EACH CELL
TO MAKE SURE IT FUNCTIONS.
THIS ALSO SHOWS IF THE CELL IS
POSITIONED CORRECTLY IN THE JAR
SO THAT THE POSITIVE AND
NEGATIVE SIGNS ON THE CELL COVER
WILL BE
ON THE CORRESPONDING POSTS.
THEY HEAT-SEAL THE COVER
AND SEAL THE PROTRUDING POSTS
WITH LEAD.
TO TEST THE SEALS,
THEY PUMP AIR INTO THE CELL,
THEN BRUSH SOAPY WATER
OVER THE COVER.
ANY BUBBLES INDICATE A GAP
TO BE RESEALED.
IN ANOTHER PART OF THE FACTORY,
WORKERS MANUALLY MOLD
VARIOUS SMALL COMPONENTS
FROM MOLTEN LEAD.
AMONG THOSE PARTS --
THE CONNECTORS
THAT LINK ONE CELL TO ANOTHER.
WORKERS WELD THEM TO THE POSTS.
THESE ARE 8-VOLT BATTERIES,
SO FOR EACH ONE,
THEY CONNECT FOUR CELLS
INSIDE A POLYETHYLENE CASE.
NOW THAT ASSEMBLY IS COMPLETE,
THE CASE COVER GOES ON.
THESE RUBBER GROMMETS KEEP WATER
FROM SEEPING INSIDE
AND SHORTING THE BATTERY.
NOW THEY FILL THE INSIDE
WITH SULFURIC ACID,
WHICH FUNCTIONS
AS AN ELECTROLYTE,
THE MEDIUM THAT HELPS
THE LEAD IN THE PLATES
CONDUCT ELECTRICITY.
Narrator: THE TIN CAN
WAS INVENTED BACK IN THE 1800s
TO PRESERVE AND PROTECT.
WE STILL RELY
ON THIS TRUSTY CONTAINER
TO KEEP A RANGE
OF PERISHABLES FRESH --
EVERYTHING FROM FOOD TO BLOOD
PLASMA TO MILITARY SUPPLIES.
AND AFTER ALL THESE YEARS
OF USE,
THE TIN CAN STILL
HAS AN AIRTIGHT REPUTATION.
IT'S TIME TO LIFT THE LID
ON THIS TRADITIONAL CONTAINER
AND GET THE INSIDE STORY
FROM THE FACTORY.
TO MAKE A TIN,
THEY TAKE A STRIP OF TIN STEEL
AND WELD IT TO JOIN THE ENDS.
THE RESULTING CYLINDRICAL SHAPE
IS THE BODY OF THE TIN,
AND IT'S ABOUT
TO BE HERMETICALLY SEALED.
THE ROTATING TOOLS
ON THIS MACHINE
STRETCH OUT THE EDGES OF
THE CYLINDER, FORMING A FLANGE.
THEY TOP OFF THE TINS
AT THIS STATION,
WHERE A SPINNING HEAD PRESSES
THE CYLINDER INTO THESE LIDS.
IT SIMULTANEOUSLY ROLLS
THE FLANGED EDGES TOGETHER
TO MAKE AN AIRTIGHT SEAL.
THIS CONTAINER
IS FOR CLASSIFIED MILITARY USE,
BUT OVER ON ANOTHER
PRODUCTION LINE,
THEY'RE MAKING
A MORE STANDARD TIN --
THE KIND
YOU WOULD PUT COFFEE IN --
SO THIS ASSEMBLY
IS MORE MECHANIZED.
IN A FRACTION OF A SECOND,
AN AUTOMATED WELDER
ROUNDS AND JOINS METAL
TO CREATE THE BODY OF A TIN.
THE TINS TRAVEL
FORWARD AND UPWARD
ON A MAGNETIC CONVEYOR SYSTEM.
THEY'RE GOING TO THE OTHER SIDE
OF THE PLANT,
WHERE THEY'LL GET
TOPS AND BOTTOMS.
THIS KIND OF TIN
HAS A REUSABLE SLIPCOVER LID
AND GETS SOME DECORATIVE WORK.
LIKE A BIG COOKIE CUTTER,
A PUNCH PRESS CUTS OUT DESIGNS
THAT HAVE BEEN PREPRINTED
ON METAL.
AT THE SAME TIME,
IT PUSHES THE CUT DESIGN
ONTO A DIE
TO FORM THE LID SHAPE.
A MAGNETIC CONVEYOR
PULLS THEM FORWARD
AND FLIPS THE LIDS
TO STACK THEM FOR PACKING.
ELSEWHERE IN THE PLANT,
THEY'RE MAKING CANS
TO GO WITH SOME OTHER LIDS.
A LINEUP OF CIRCULAR BLADES
SLICES THROUGH TIN SHEETS.
THE CUT PIECES ACCUMULATE
IN STACKS.
THEY LOAD THE FLAT PIECES OF TIN
INTO A CYLINDER,
WHERE THEY'RE CURLED INTO TUBES.
AS THEY EXIT, ROBOTIC ARMS
MAKE SEAMS IN THE ROLLED TINS,
AND A PRESS APPLIES FORCE
TO LOCK THEM.
THIS LOCK SEAM IS AN ALTERNATIVE
TO THE WELDED ONE
WE SAW EARLIER.
NOW, ANOTHER MAGNETIC CONVEYOR
PULLS THE TIN TUBES FORWARD,
AND THEY GO FOR A SPIN
WHILE ROLLERS FLANGE THE EDGES
SO THAT THE BOTTOMS
CAN BE ATTACHED.
THEN A PUNCH CUTTER
MAKES THE BOTTOMS,
MAKING SURE
TO RECYCLE THE SCRAPS.
THE CAN BOTTOMS SPIN OUT
OF THE PUNCH CUTTER
BEFORE LANDING
ON THE NEXT MAGNETIZED CONVEYOR.
THEY GET A SQUIRT
OF LIQUID RUBBER,
WHICH WILL HARDEN INTO A GASKET
TO PREVENT LEAKS IN THE CAN.
A FOLDING MACHINE
NOW LOCKS THE BOTTOMS
TO THE TUBES AS THEY SPIN.
MORE THAN 12,000 CANS PER HOUR
CAN BE MADE
ON THIS HIGH-SPEED LINE...
...FROM A BLANK PIECE OF STEEL
TO A VERY USEFUL CONTAINER.
WHATEVER THEIR CONTENTS,
THESE TINS ARE DESTINED
FOR A FULL LIFE --
THAT IS, UNTIL SOMEONE DECIDES
TO EMPTY THEM.
Narrator: IT'S TIME TO TURN
OUR CAMERA'S EYE
ON THE CAMERA'S EYE.
OPTICAL LENSES
ARE REALLY SEVERAL LENSES
COMBINED INTO A SINGLE UNIT.
TOGETHER, THEY RE-CREATE
AN IMAGE BY BENDING LIGHT RAYS,
SO THEY CONVERGE INTO A COMMON
POINT CALLED THE FOCAL POINT.
THESE TELEVISION LENSES START
WITH A VERY PRECISE DESIGN.
A DIAMOND BLADE
SLICES UP A BLOCK
OF SPECIALLY SELECTED
OPTICAL GLASS,
WHILE COOLANT PREVENTS THE BLADE
FROM BURNING IT.
THE SLICES THEN GO UNDER
A DIAMOND DRILL,
WHICH CUTS SEVERAL PUCK-SIZED
DISKS FROM ONE GLASS SLICE.
THE OPERATOR IS CAREFUL
TO KEEP WASTE TO A MINIMUM.
OPTICAL GLASS COSTS UP TO $1,000
FOR 2.2 POUNDS.
DURING THE DRILLING,
THE OPTICAL GLASS SITS
ON A THINNER PIECE OF GLASS
COVERED WITH WAX.
AS THE WAX IS MELTED, THE DISKS
ARE EASILY PULLED AWAY.
NEXT, A DEVICE SPINS
ONE OF THE DISKS,
WHILE A WHEEL OVERHEAD
SCULPTS IT INTO A LENS.
THE OPERATOR CHECKS EACH LENS
FOR CHIPS,
AND THIS ONE LOOKS SMOOTH.
THIS TARLIKE SUBSTANCE
IS CALLED PITCH.
THE EDGES OF THE LENS
HAVE BEEN BUILT UP WITH TAPE
TO CONTAIN THE PITCH.
THEY COMPLETELY COAT THE
UNDERSIDE OF THE LENS WITH IT.
SEVERAL PITCH-COVERED LENSES
ARE NOW IN A METAL SHELL.
A WORKER PICKS UP A HOT ALUMINUM
DOME CALLED A BLOCKING BODY.
HE PRESSES IT ONTO
THE PITCH-COVERED LENSES,
AND THE PITCH MELTS ONTO IT.
DOUSING IT WITH WATER
CAUSES THE PITCH TO HARDEN,
SEALING THE LENSES
TO THE BLOCKING BODY.
THE BLOCKING BODY
IS NOW UPSIDE DOWN
AND ACTING AS A HOLDING DEVICE
AS IT OSCILLATES
ON A SPINNING GRINDING SHELL.
THE GRINDING MAKES
THE SURFACE OF THE LENSES
UNIFORM AND SMOOTH.
THEY PLACE A POLISHER
ON THE LENSES.
IT'S LUBRICATED
WITH A VERY FINE ABRASIVE.
FOR ABOUT AN HOUR,
THE POLISHER OSCILLATES
WHILE THE BLOCK SPINS.
POLISHING MAKES THE LENSES
SMOOTH AND TRANSPARENT.
IT ALSO GIVES THEM
AN EVEN MORE CURVED PROFILE.
THE LENSES HAVE BEEN REMOVED
FROM THE BLOCK,
AND IT'S TIME TO CUT
THE DIAMETER DOWN TO SIZE.
USING A MICROSCOPE,
A TECHNICIAN CENTERS A LENS
BETWEEN TWO BRASS CHUCKS.
A DIAMOND BLADE AT THE BACK
CUTS THE LENS
AS A TECHNICIAN MONITORS IT.
HE'S MAKING SURE THE DIAMETER
AND AXIS OF THE LENS
HAVE A COMMON CENTER.
NEXT, THEY GROUP SOME LENSES
ON ROUND RACKS CALLED PLANETS.
THEIR UNIVERSE
IS A VACUUM CHAMBER.
THE TECHNICIAN CLOSES THE DOOR,
AND THE PLANETS
CONTINUE THEIR ORBIT.
INSIDE THIS VACUUM,
AN ELECTRON BEAM
EVAPORATES COATING MATERIALS.
THE VAPOR RISES TO GIVE
THE LENSES A PROTECTIVE COAT.
A COMPUTER MONITORS THE RATE
OF EVAPORATION AND THE COATING.
BUT THERE'S MUCH MORE TO COME.
UP NEXT, THIS PROCESS
REALLY GETS VISUAL
AS ALL THE PIECES
OF A CAMERA LENS COME TOGETHER.
Narrator: THE OPTICAL LENS
IS THE ULTIMATE IMAGE MAKER.
ALONG WITH CAMERAS,
YOU'LL FIND THEM IN PROJECTORS,
MICROSCOPES, LASER SCANNERS,
AND X-RAY EQUIPMENT.
THEY GIVE US A CLOSEUP VIEW
OF SO MANY THINGS.
IT SEEMS ONLY APPROPRIATE
THAT WE TAKE A CLOSEUP LOOK
AT THE OPTICAL LENS ITSELF.
THE LENSES
HAVE JUST SPENT THREE HOURS
GETTING A PROTECTIVE FINISH.
IT'S TIME TO WIPE ANY RESIDUE
AND MAKE SURE THEY'RE PERFECT.
THIS PARTICULAR LENS IS CONCAVE.
SHE COVERS IT TO PROTECT IT
WHILE SHE CLEANS
AND INSPECTS THE LENS
WITH THE OPPOSITE PROFILE --
CONVEX.
THEN THE CONVEX LENS
GOES TO ANOTHER TECHNICIAN,
WHO PLACES IT
IN A HOLDING DEVICE.
HE LOOKS INTO A MICROSCOPE AND
ADJUSTS THE POSITION OF THE LENS
UNTIL IT'S OPTICALLY CENTERED.
HE USES WAX TO KEEP THE LENS
FROM SHIFTING
IN THE HOLDING DEVICE.
THEY GIVE THE LENS
ANOTHER CLEANING.
EACH ONE MUST BE
ABSOLUTELY SPOTLESS
BEFORE THEY PROCEED
TO THE NEXT STEP.
OTHERWISE, DUST PARTICLES
COULD BECOME TRAPPED
WITHIN THE OPTICAL SYSTEM
AND AFFECT IMAGE QUALITY.
NOW THAT THE SURFACE OF
THE CONVEX LENS IS IMMACULATE,
SHE DABS OPTICAL CEMENT
ONTO THE CENTER OF IT.
SHE GIVES THE OTHER CONCAVE LENS
A LITTLE MORE SCRUTINY
BEFORE SHE CEMENTS IT
ONTO THE CONVEX LENS.
SHE APPLIES PRESSURE
TO SPREAD THE CEMENT
BETWEEN THE TWO LENSES.
CEMENTING THEM TOGETHER
MEANS THEY'LL BE LESS LIKELY
TO SHIFT AROUND
IN THE LENS BARREL.
SHE CHECKS FOR DUST
ONE MORE TIME.
THEN IT'S UNDER THE MICROSCOPE
FOR AN OPTICAL ALIGNMENT
OF THIS DOUBLE LENS.
BECAUSE THE CEMENT
ISN'T YET DRY,
HE CAN PUSH THE TOP LENS AROUND
AND ADJUST ITS POSITION.
NEXT, THEY PREP THE BARREL
THAT WILL HOLD THE LENSES.
A TECHNICIAN
TRACES OUT LETTERING
USING A STYLUS ATTACHED
TO A SHARP TOOL
THAT ENGRAVES INFORMATION
ONTO THE LENS BARREL.
IT PRINTS TECHNICAL DETAILS
THAT WILL TELL THE PHOTOGRAPHER
JUST WHAT THE LENS WILL DO --
THINGS LIKE FOCAL LENGTH,
THE F-NUMBER,
AND THE SIZE
OF THE APERTURE OPENING.
THESE REFERENCE POINTS
ALLOW THE USER
TO PULL A PICTURE INTO FOCUS
AT THE DESIRED MAGNIFICATION.
NOW THEY DOUBLE-CHECK THE DESIGN
FOR THIS COMPLEX OPTICAL SYSTEM
AND BEGIN TO PULL
ALL THE PIECES TOGETHER.
THIS SINGLET, OR SINGLE LENS,
GOES INTO
THE METAL BARREL FIRST.
OTHER LENSES
WITH VARIOUS CURVATURES
AND DIMENSIONS FOLLOW.
SHE PLACES METAL SPACERS BETWEEN
THE LENSES TO SEPARATE THEM.
PROPER SPACING WILL PREVENT
ABERRATIONS IN THE IMAGE,
SUCH AS BLURRING.
BETWEEN INSTALLATIONS,
SHE COVERS THE BARREL WITH
A PIECE OF LINT-FREE PLASTIC
BECAUSE ELIMINATING DUST
CONTINUES TO BE A NECESSITY.
ONE FLECK COULD RUIN
THIS ENTIRE ASSEMBLY.
USING TWEEZERS, SHE COAXES
THE LAST LENS INTO THE BARREL.
SHE INSTALLS A RETAINING RING TO
HOLD THE STACK OF LENSES DOWN.
THEN SHE LOCKS IT INTO PLACE.
THERE'S ONE FINAL INSPECTION.
SHE EXAMINES THE ASSEMBLED
OPTICAL LENS FROM ALL ANGLES.
IT TAKES A TOTAL OF SIX WEEKS
TO MAKE ONE
OF THESE OPTICAL LENSES,
AND IN THE END,
IT'S PICTURE-PERFECT.
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DISCOVERY COMMUNICATIONS, INC.
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TODAY ON "HOW IT'S MADE"...
DEEP-CYCLE BATTERIES...
...TINS...
...AND OPTICAL LENSES.
A DEEP-CYCLE BATTERY IS WHAT
YOU FIND IN SUCH VEHICLES
AS TRAINS, BOATS, R.V.s,
AND FORKLIFT TRUCKS.
WHEREAS A CAR BATTERY PROVIDES
A QUICK SURGE OF CURRENT
TO START THE ENGINE,
A DEEP-CYCLE BATTERY PROVIDES
A STEADY AMOUNT OF CURRENT
OVER A LONG PERIOD OF TIME.
DEEP-CYCLE BATTERIES RANGE
FROM 2 TO 48 VOLTS.
THEIR POWER IS GENERATED
BY CELLS,
A GROUP OF LEAD PLATES COATED
IN LEAD OXIDE AND ACID.
THIS CASTING MACHINE
PRODUCES LEAD GRIDS
THAT WILL BECOME THE PLATES
IN THE POWER CELLS.
THE MACHINE POURS MOLTEN LEAD
INTO GRID-SHAPED MOLDS.
WATER CIRCULATING
THROUGH THE MOLD
HARDENS THE METAL
IN JUST FIVE SECONDS.
THE MACHINE CASTS
TWO TYPES OF GRIDS --
NEGATIVES AND POSITIVES.
THE NEXT MACHINE COATS THE GRIDS
WITH A CHEMICAL PASTE
THAT CONTAINS
LEAD OXIDE AND ACID.
THE POSITIVES
GET ONE PASTE FORMULATION.
THE NEGATIVES, A DIFFERENT ONE.
THE GRIDS ARE NOW CALLED PLATES.
WORKERS STACK THEM IN CASES,
ALTERNATING
POSITIVE AND NEGATIVE,
THEN DROP THEM IN TANKS
OF SULFURIC ACID TO CHARGE.
THE LEAD OXIDE AND ACID
IN THE PASTE STORE THE POWER.
AFTER CHARGING
FOR 24 TO 72 HOURS,
DEPENDING ON THE MODEL,
THE PLATES GO INTO A MACHINE
THAT WASHES THEM THREE TIMES
TO REMOVE ACID RESIDUE,
WHICH, IF LEFT,
WOULD CORRODE THE METAL.
THE CHARGING PROCESS
BLACKENS THE PLATES,
WHICH ARE NOW CALLED
DRY-CHARGE PLATES.
A MACHINE WRAPS EACH POSITIVE
IN GLASS-STRAND MATTING,
AN INSULATION MATERIAL
SIMILAR TO FIBERGLASS,
THEN IN A PLASTIC ENVELOPE.
THESE COVERINGS PROTECT
THE PLATES FROM SHORT CIRCUITS.
WORKERS STACK
THE PLATES AGAIN --
POSITIVE, NEGATIVE,
POSITIVE, NEGATIVE.
THIS TIME, THOUGH, EACH STACK
CONTAINS A SPECIFIC NUMBER --
FROM 5 TO 33 PLATES,
DEPENDING ON THE BATTERY MODEL.
EACH STACK WILL BECOME ONE CELL.
A CELL PROVIDES
2 VOLTS OF ELECTRICITY.
EACH PLATE HAS A TAB.
A ROBOTIC MACHINE CLEANS
THE TABS WITH A WIRE BRUSH
AND A CHEMICAL SOLUTION
CALLED FLUX.
THEN IT DIPS THE TABS
IN MOLTEN TIN.
THIS TIN COATING
WILL IMPROVE THE BOND
WHEN THEY SOLDER
THE TABS TOGETHER.
THE ROBOT WIPES THE TABS
ON A FLUX-IMBUED SPONGE
TO CLEAN THEIR SURFACE
ONCE AGAIN...
...THEN DROPS THE CELLS INTO
A MOLD CONTAINING MOLTEN LEAD.
THIS SOLDERS THE TABS TOGETHER,
BONDING THE PLATES
WITHIN EACH CELL.
THE PROCESS CASTS TWO LEAD POSTS
ON THE CELL'S POSITIVE SIDE
AND TWO ON ITS NEGATIVE SIDE.
THESE POSTS
WILL CONNECT THE CELLS
AND BUILD THE REQUIRED VOLTAGE.
NEXT, EACH CELL GOES
INTO A POLYPROPYLENE CASING
CALLED A JAR.
THEY TEST EACH CELL
TO MAKE SURE IT FUNCTIONS.
THIS ALSO SHOWS IF THE CELL IS
POSITIONED CORRECTLY IN THE JAR
SO THAT THE POSITIVE AND
NEGATIVE SIGNS ON THE CELL COVER
WILL BE
ON THE CORRESPONDING POSTS.
THEY HEAT-SEAL THE COVER
AND SEAL THE PROTRUDING POSTS
WITH LEAD.
TO TEST THE SEALS,
THEY PUMP AIR INTO THE CELL,
THEN BRUSH SOAPY WATER
OVER THE COVER.
ANY BUBBLES INDICATE A GAP
TO BE RESEALED.
IN ANOTHER PART OF THE FACTORY,
WORKERS MANUALLY MOLD
VARIOUS SMALL COMPONENTS
FROM MOLTEN LEAD.
AMONG THOSE PARTS --
THE CONNECTORS
THAT LINK ONE CELL TO ANOTHER.
WORKERS WELD THEM TO THE POSTS.
THESE ARE 8-VOLT BATTERIES,
SO FOR EACH ONE,
THEY CONNECT FOUR CELLS
INSIDE A POLYETHYLENE CASE.
NOW THAT ASSEMBLY IS COMPLETE,
THE CASE COVER GOES ON.
THESE RUBBER GROMMETS KEEP WATER
FROM SEEPING INSIDE
AND SHORTING THE BATTERY.
NOW THEY FILL THE INSIDE
WITH SULFURIC ACID,
WHICH FUNCTIONS
AS AN ELECTROLYTE,
THE MEDIUM THAT HELPS
THE LEAD IN THE PLATES
CONDUCT ELECTRICITY.
Narrator: THE TIN CAN
WAS INVENTED BACK IN THE 1800s
TO PRESERVE AND PROTECT.
WE STILL RELY
ON THIS TRUSTY CONTAINER
TO KEEP A RANGE
OF PERISHABLES FRESH --
EVERYTHING FROM FOOD TO BLOOD
PLASMA TO MILITARY SUPPLIES.
AND AFTER ALL THESE YEARS
OF USE,
THE TIN CAN STILL
HAS AN AIRTIGHT REPUTATION.
IT'S TIME TO LIFT THE LID
ON THIS TRADITIONAL CONTAINER
AND GET THE INSIDE STORY
FROM THE FACTORY.
TO MAKE A TIN,
THEY TAKE A STRIP OF TIN STEEL
AND WELD IT TO JOIN THE ENDS.
THE RESULTING CYLINDRICAL SHAPE
IS THE BODY OF THE TIN,
AND IT'S ABOUT
TO BE HERMETICALLY SEALED.
THE ROTATING TOOLS
ON THIS MACHINE
STRETCH OUT THE EDGES OF
THE CYLINDER, FORMING A FLANGE.
THEY TOP OFF THE TINS
AT THIS STATION,
WHERE A SPINNING HEAD PRESSES
THE CYLINDER INTO THESE LIDS.
IT SIMULTANEOUSLY ROLLS
THE FLANGED EDGES TOGETHER
TO MAKE AN AIRTIGHT SEAL.
THIS CONTAINER
IS FOR CLASSIFIED MILITARY USE,
BUT OVER ON ANOTHER
PRODUCTION LINE,
THEY'RE MAKING
A MORE STANDARD TIN --
THE KIND
YOU WOULD PUT COFFEE IN --
SO THIS ASSEMBLY
IS MORE MECHANIZED.
IN A FRACTION OF A SECOND,
AN AUTOMATED WELDER
ROUNDS AND JOINS METAL
TO CREATE THE BODY OF A TIN.
THE TINS TRAVEL
FORWARD AND UPWARD
ON A MAGNETIC CONVEYOR SYSTEM.
THEY'RE GOING TO THE OTHER SIDE
OF THE PLANT,
WHERE THEY'LL GET
TOPS AND BOTTOMS.
THIS KIND OF TIN
HAS A REUSABLE SLIPCOVER LID
AND GETS SOME DECORATIVE WORK.
LIKE A BIG COOKIE CUTTER,
A PUNCH PRESS CUTS OUT DESIGNS
THAT HAVE BEEN PREPRINTED
ON METAL.
AT THE SAME TIME,
IT PUSHES THE CUT DESIGN
ONTO A DIE
TO FORM THE LID SHAPE.
A MAGNETIC CONVEYOR
PULLS THEM FORWARD
AND FLIPS THE LIDS
TO STACK THEM FOR PACKING.
ELSEWHERE IN THE PLANT,
THEY'RE MAKING CANS
TO GO WITH SOME OTHER LIDS.
A LINEUP OF CIRCULAR BLADES
SLICES THROUGH TIN SHEETS.
THE CUT PIECES ACCUMULATE
IN STACKS.
THEY LOAD THE FLAT PIECES OF TIN
INTO A CYLINDER,
WHERE THEY'RE CURLED INTO TUBES.
AS THEY EXIT, ROBOTIC ARMS
MAKE SEAMS IN THE ROLLED TINS,
AND A PRESS APPLIES FORCE
TO LOCK THEM.
THIS LOCK SEAM IS AN ALTERNATIVE
TO THE WELDED ONE
WE SAW EARLIER.
NOW, ANOTHER MAGNETIC CONVEYOR
PULLS THE TIN TUBES FORWARD,
AND THEY GO FOR A SPIN
WHILE ROLLERS FLANGE THE EDGES
SO THAT THE BOTTOMS
CAN BE ATTACHED.
THEN A PUNCH CUTTER
MAKES THE BOTTOMS,
MAKING SURE
TO RECYCLE THE SCRAPS.
THE CAN BOTTOMS SPIN OUT
OF THE PUNCH CUTTER
BEFORE LANDING
ON THE NEXT MAGNETIZED CONVEYOR.
THEY GET A SQUIRT
OF LIQUID RUBBER,
WHICH WILL HARDEN INTO A GASKET
TO PREVENT LEAKS IN THE CAN.
A FOLDING MACHINE
NOW LOCKS THE BOTTOMS
TO THE TUBES AS THEY SPIN.
MORE THAN 12,000 CANS PER HOUR
CAN BE MADE
ON THIS HIGH-SPEED LINE...
...FROM A BLANK PIECE OF STEEL
TO A VERY USEFUL CONTAINER.
WHATEVER THEIR CONTENTS,
THESE TINS ARE DESTINED
FOR A FULL LIFE --
THAT IS, UNTIL SOMEONE DECIDES
TO EMPTY THEM.
Narrator: IT'S TIME TO TURN
OUR CAMERA'S EYE
ON THE CAMERA'S EYE.
OPTICAL LENSES
ARE REALLY SEVERAL LENSES
COMBINED INTO A SINGLE UNIT.
TOGETHER, THEY RE-CREATE
AN IMAGE BY BENDING LIGHT RAYS,
SO THEY CONVERGE INTO A COMMON
POINT CALLED THE FOCAL POINT.
THESE TELEVISION LENSES START
WITH A VERY PRECISE DESIGN.
A DIAMOND BLADE
SLICES UP A BLOCK
OF SPECIALLY SELECTED
OPTICAL GLASS,
WHILE COOLANT PREVENTS THE BLADE
FROM BURNING IT.
THE SLICES THEN GO UNDER
A DIAMOND DRILL,
WHICH CUTS SEVERAL PUCK-SIZED
DISKS FROM ONE GLASS SLICE.
THE OPERATOR IS CAREFUL
TO KEEP WASTE TO A MINIMUM.
OPTICAL GLASS COSTS UP TO $1,000
FOR 2.2 POUNDS.
DURING THE DRILLING,
THE OPTICAL GLASS SITS
ON A THINNER PIECE OF GLASS
COVERED WITH WAX.
AS THE WAX IS MELTED, THE DISKS
ARE EASILY PULLED AWAY.
NEXT, A DEVICE SPINS
ONE OF THE DISKS,
WHILE A WHEEL OVERHEAD
SCULPTS IT INTO A LENS.
THE OPERATOR CHECKS EACH LENS
FOR CHIPS,
AND THIS ONE LOOKS SMOOTH.
THIS TARLIKE SUBSTANCE
IS CALLED PITCH.
THE EDGES OF THE LENS
HAVE BEEN BUILT UP WITH TAPE
TO CONTAIN THE PITCH.
THEY COMPLETELY COAT THE
UNDERSIDE OF THE LENS WITH IT.
SEVERAL PITCH-COVERED LENSES
ARE NOW IN A METAL SHELL.
A WORKER PICKS UP A HOT ALUMINUM
DOME CALLED A BLOCKING BODY.
HE PRESSES IT ONTO
THE PITCH-COVERED LENSES,
AND THE PITCH MELTS ONTO IT.
DOUSING IT WITH WATER
CAUSES THE PITCH TO HARDEN,
SEALING THE LENSES
TO THE BLOCKING BODY.
THE BLOCKING BODY
IS NOW UPSIDE DOWN
AND ACTING AS A HOLDING DEVICE
AS IT OSCILLATES
ON A SPINNING GRINDING SHELL.
THE GRINDING MAKES
THE SURFACE OF THE LENSES
UNIFORM AND SMOOTH.
THEY PLACE A POLISHER
ON THE LENSES.
IT'S LUBRICATED
WITH A VERY FINE ABRASIVE.
FOR ABOUT AN HOUR,
THE POLISHER OSCILLATES
WHILE THE BLOCK SPINS.
POLISHING MAKES THE LENSES
SMOOTH AND TRANSPARENT.
IT ALSO GIVES THEM
AN EVEN MORE CURVED PROFILE.
THE LENSES HAVE BEEN REMOVED
FROM THE BLOCK,
AND IT'S TIME TO CUT
THE DIAMETER DOWN TO SIZE.
USING A MICROSCOPE,
A TECHNICIAN CENTERS A LENS
BETWEEN TWO BRASS CHUCKS.
A DIAMOND BLADE AT THE BACK
CUTS THE LENS
AS A TECHNICIAN MONITORS IT.
HE'S MAKING SURE THE DIAMETER
AND AXIS OF THE LENS
HAVE A COMMON CENTER.
NEXT, THEY GROUP SOME LENSES
ON ROUND RACKS CALLED PLANETS.
THEIR UNIVERSE
IS A VACUUM CHAMBER.
THE TECHNICIAN CLOSES THE DOOR,
AND THE PLANETS
CONTINUE THEIR ORBIT.
INSIDE THIS VACUUM,
AN ELECTRON BEAM
EVAPORATES COATING MATERIALS.
THE VAPOR RISES TO GIVE
THE LENSES A PROTECTIVE COAT.
A COMPUTER MONITORS THE RATE
OF EVAPORATION AND THE COATING.
BUT THERE'S MUCH MORE TO COME.
UP NEXT, THIS PROCESS
REALLY GETS VISUAL
AS ALL THE PIECES
OF A CAMERA LENS COME TOGETHER.
Narrator: THE OPTICAL LENS
IS THE ULTIMATE IMAGE MAKER.
ALONG WITH CAMERAS,
YOU'LL FIND THEM IN PROJECTORS,
MICROSCOPES, LASER SCANNERS,
AND X-RAY EQUIPMENT.
THEY GIVE US A CLOSEUP VIEW
OF SO MANY THINGS.
IT SEEMS ONLY APPROPRIATE
THAT WE TAKE A CLOSEUP LOOK
AT THE OPTICAL LENS ITSELF.
THE LENSES
HAVE JUST SPENT THREE HOURS
GETTING A PROTECTIVE FINISH.
IT'S TIME TO WIPE ANY RESIDUE
AND MAKE SURE THEY'RE PERFECT.
THIS PARTICULAR LENS IS CONCAVE.
SHE COVERS IT TO PROTECT IT
WHILE SHE CLEANS
AND INSPECTS THE LENS
WITH THE OPPOSITE PROFILE --
CONVEX.
THEN THE CONVEX LENS
GOES TO ANOTHER TECHNICIAN,
WHO PLACES IT
IN A HOLDING DEVICE.
HE LOOKS INTO A MICROSCOPE AND
ADJUSTS THE POSITION OF THE LENS
UNTIL IT'S OPTICALLY CENTERED.
HE USES WAX TO KEEP THE LENS
FROM SHIFTING
IN THE HOLDING DEVICE.
THEY GIVE THE LENS
ANOTHER CLEANING.
EACH ONE MUST BE
ABSOLUTELY SPOTLESS
BEFORE THEY PROCEED
TO THE NEXT STEP.
OTHERWISE, DUST PARTICLES
COULD BECOME TRAPPED
WITHIN THE OPTICAL SYSTEM
AND AFFECT IMAGE QUALITY.
NOW THAT THE SURFACE OF
THE CONVEX LENS IS IMMACULATE,
SHE DABS OPTICAL CEMENT
ONTO THE CENTER OF IT.
SHE GIVES THE OTHER CONCAVE LENS
A LITTLE MORE SCRUTINY
BEFORE SHE CEMENTS IT
ONTO THE CONVEX LENS.
SHE APPLIES PRESSURE
TO SPREAD THE CEMENT
BETWEEN THE TWO LENSES.
CEMENTING THEM TOGETHER
MEANS THEY'LL BE LESS LIKELY
TO SHIFT AROUND
IN THE LENS BARREL.
SHE CHECKS FOR DUST
ONE MORE TIME.
THEN IT'S UNDER THE MICROSCOPE
FOR AN OPTICAL ALIGNMENT
OF THIS DOUBLE LENS.
BECAUSE THE CEMENT
ISN'T YET DRY,
HE CAN PUSH THE TOP LENS AROUND
AND ADJUST ITS POSITION.
NEXT, THEY PREP THE BARREL
THAT WILL HOLD THE LENSES.
A TECHNICIAN
TRACES OUT LETTERING
USING A STYLUS ATTACHED
TO A SHARP TOOL
THAT ENGRAVES INFORMATION
ONTO THE LENS BARREL.
IT PRINTS TECHNICAL DETAILS
THAT WILL TELL THE PHOTOGRAPHER
JUST WHAT THE LENS WILL DO --
THINGS LIKE FOCAL LENGTH,
THE F-NUMBER,
AND THE SIZE
OF THE APERTURE OPENING.
THESE REFERENCE POINTS
ALLOW THE USER
TO PULL A PICTURE INTO FOCUS
AT THE DESIRED MAGNIFICATION.
NOW THEY DOUBLE-CHECK THE DESIGN
FOR THIS COMPLEX OPTICAL SYSTEM
AND BEGIN TO PULL
ALL THE PIECES TOGETHER.
THIS SINGLET, OR SINGLE LENS,
GOES INTO
THE METAL BARREL FIRST.
OTHER LENSES
WITH VARIOUS CURVATURES
AND DIMENSIONS FOLLOW.
SHE PLACES METAL SPACERS BETWEEN
THE LENSES TO SEPARATE THEM.
PROPER SPACING WILL PREVENT
ABERRATIONS IN THE IMAGE,
SUCH AS BLURRING.
BETWEEN INSTALLATIONS,
SHE COVERS THE BARREL WITH
A PIECE OF LINT-FREE PLASTIC
BECAUSE ELIMINATING DUST
CONTINUES TO BE A NECESSITY.
ONE FLECK COULD RUIN
THIS ENTIRE ASSEMBLY.
USING TWEEZERS, SHE COAXES
THE LAST LENS INTO THE BARREL.
SHE INSTALLS A RETAINING RING TO
HOLD THE STACK OF LENSES DOWN.
THEN SHE LOCKS IT INTO PLACE.
THERE'S ONE FINAL INSPECTION.
SHE EXAMINES THE ASSEMBLED
OPTICAL LENS FROM ALL ANGLES.
IT TAKES A TOTAL OF SIX WEEKS
TO MAKE ONE
OF THESE OPTICAL LENSES,
AND IN THE END,
IT'S PICTURE-PERFECT.
CAPTIONS PAID FOR BY
DISCOVERY COMMUNICATIONS, INC.
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