All language subtitles for S05E08 - Suits of Armor; Street Light Poles; Bent Hardwood; Membrane Switches (576p AMZN WEB-DL x265 Garshasp)_track4_[eng]

Narrator:
Today on "How it's made"...

Suits of armor...

...Street-light bulbs...

...Bent hardwood...

...And membrane switches.

If you're the type of guy

Who finds wearing
A tie uncomfortable,

Try sporting a suit of armor.

Armor reached its peak during
The battle-filled 15th century.

Initially, it was made
Of chain mail,

Tiny rings of metal
Linked together.

Then, for greater protection,

Knights began wearing
Plate armor,

Suits made from large pieces
Of steel.

Today, armorers make
This obsolete battle gear

Mostly for historical
Re-enactment buffs.

This workshop specializes
In custom-made suits of armor.

The armorer has to take
45 different measurements

Just to prepare the pattern.

He traces each pattern piece
On a steel sheet

That's about 1/16
Of an inch thick.

Then he cuts along
The trace line with a band saw.

This is the breastplate, which
Covers the chest and abdomen.

Now he begins to shape the piece
Using an automatic hammer.

There's no mold or template
To guide him.

He works strictly by eye.

Now that he has the basic shape,

He refines it using
A manual hammer.

He strikes the metal
Against an upright log,

A bag of lead beads
Cushioning the blows.

This prevents the metal
From deforming.

A few lighter blows without
Cushioning in select spots

To finalize the shape.

Until now, he's been hammering
The inside of the breastplate.

Now he works the outside.

He smoothes the metal surface,
A process known as planishing.

Now, using a different
Automatic hammerhead,

He stretches out
The breastplate's bottom edge

To form a rim angling outward.

He places the piece on an anvil,

Then, using a manual hammer,
Planishes the rim.

When you wear this heavy
Metal breastplate,

The rim takes some of the weight
Off your shoulders

By distributing it
Over your hips.

The armorer checks the shape,

Then makes
Any necessary adjustments.

Now, using several
Different hammers again,

He works his way around the rest
Of the breastplate,

Gradually rolling the edge onto
Itself to form a rounded lip.

Rolling the metal onto itself
To form the lip

Reinforces the perimeter
Of the breastplate,

And the rounded edge
Prevents the sharp metal

From cutting the skin.

The breastplate is now ready
For the finishing touches.

First, the armorer
Smoothes the surface

With medium-grit sandpaper...

Then with fine-grit sandpaper...

Then -- the last step --

With fine-grit paper
And a polishing compound.

Some breastplates
Have an articulated styling.

For this model, the armorer
Uses three brass rivets

To attach the sections.

He fastens them loosely
To enable the pieces to move.

Then, using rivets again,
He attaches leather straps.

A suit of armor is made up of
About 20 different components,

Such as the front and back
Shin guards called grieves...

...Armor-and-leather gloves
Called gauntlets...

...Shoulder pieces
Called pauldrons...

...And, of course,
The helmet and visor.

A knight would don a suit
Of armor from the bottom up,

Otherwise the weight
Of the top components

Would have him keeling over,
Half-dressed.

In the middle ages,

A suit of armor cost
As much as a small farm.

It was a prized luxury
Only the nobility could afford.

Being a modern-day
Knight in shining armor

Doesn't come cheap, either.

A base-model suit
Costs about $3,000,

An elaborate one up to $20,000.

Narrator: we take
Well-lit streets for granted,

But there was a time
When venturing out at night

Meant traveling
In complete darkness.

In 1814, the first gas lights

Lit up the streets
Of london, england.

The first electric streetlights

Illuminated a public square
In cleveland, ohio, in 1879.

These streetlight poles are made
Of what's called composite,

A combination of fiberglass
And epoxy resin.

Epoxy resin is a gooey, liquid
Plastic mixed with a hardener.

The factory constructs each pole
On a mandrel,

A long, tapered metal cylinder.

Workers first lubricate
The surface.

Then they take what's called
A fiberglass filament,

A string composed of 2,200
Tiny fiberglass strands.

They'll wind dozens of filaments
Around the mandrel

To create the pole,

But first, the filaments go
Through a bath of epoxy resin.

This resin is moldable

And, once it's heat-cured,
Maintains its shape.

Once the filaments
Come out of the bath,

A machine
Called a filament winder

Wraps them around
The rotating mandrel.

The speed of rotation

In relation to the speed
Of the winder is critical

Because it dictates the angles
Of the fibers.

The lower the angle,
The more that part of the pole

Will be able to withstand
The wind

And provide constant,
Stable lighting.

When a pole bends in the wind,
The light appears to flicker.

The number of filament layers

Depends on the design
Of each specific pole,

And that's determined
By a couple of factors.

First, the type of light fixture
The pole will hold --

The bigger the fixture,
The stiffer the pole has to be.

The other factor is wind.

The windier the location,
The stronger the pole has to be.

Once the winding's done,

The mandrel moves on
To the curing station.

They pump pressurized steam

Into the hollow inside
Of the mandrel.

The heat kick-starts
The hardener in the epoxy resin.

This solidifies the resin
And cures it.

The mandrel rotates
So that the pole cures evenly.

Curing time depends
On the length of the pole

And how many filaments
It's made of.

To help extract the pole,

They pump cold water
Through the mandrel.

This makes the steel mandrel
Contract, loosening the pole.

Remember how workers lubricated
The surface of the mandrel

Before winding the filaments?

Because of that,
The pole just slides off.

The pole now moves on
To the finishing stages.

First, an automated sander
Works the surface.

The customer can order from
A choice of surface textures,

From smooth to rough.

Sanding takes just
A few minutes.

Now a saw makes a neat cut
At the top of the pole

Where the metal tenon will go.

A tenon is the component

That'll hold the light fixture
To the pole.

This particular model
Has an arched mounting arm.

The composite has cooled a bit
Since curing,

So they reheat it
To make it flexible.

After a bending machine
Makes the curve,

They spray cold water inside
To cool the material.

This registers the curve
In the resin's memory,

Setting the bent shape.

Now they cut out the hand hole,

The opening
Through which the electrician

Will connect the underground
Wire to the fixture wiring.

Workers then spray the pole
With urethane paint.

The paint acts like sunscreen,

Protecting the composite
From damaging ultraviolet rays.

This grommet hole will connect
To the underground pipe

That contains
The electrical wires.

After installing a cover
Over the hand hole,

It's time to assemble
The parts --

The underground pipe
To the pole...

...And the pole to the tenon
And light fixture.

Narrator: many products
Have rounded components

Made of solid hardwood.

Often, the companies
That make these products

Hire factories that specialize
In wood-bending

To prepare these components
For them.

Bending wood may sound simple,
But it isn't.

It takes a lot of preparation
And skill

To bend wood
Without cracking it.

The best type of wood to bend
Is hardwood.

Its fibers react better
To heat and moisture

Than softwood fibers do
And, therefore, curve nicely.

If you bend softwood,
It wrinkles.

The wood first goes
Into an outdoor dryer

To bring its humidity level down
To between 15% and 20%.

This prevents the wood
From expanding and contracting

After it's bent.

This air-drying process
Takes up to a week.

Once the wood is dry,

A powerful trimmer saws the
Pieces to the required length,

An edger to the required width.

Now that the wood pieces
Are the right dimensions,

They go into what's called
A steaming box.

This superficially
Rehumidifies them

So that they become
Somewhat flexible.

This takes
From 10 to 45 minutes,

Depending on the type of wood
And its thickness.

This humidity will later
Evaporate out of the wood.

Now the pieces go into a press,
Sandwiched between two forms

In the shape of the curve
To be made.

The press applies both pressure
And heat --

Pressure to bend the wood,

Heat generated by
A high-voltage electric current

To cure it,
Setting the new shape.

How long the pieces stay
In the press

Depends again on the species
And dimensions.

Generally, it takes
From 20 minutes to an hour.

Making this particular type of
Curve is called crown bending.

Workers measure each piece
Against the template

To ensure the curve
Is just right.

The factory
Uses the same process

To bend these pieces
Into a different shape.

It's critical to use

Just the right amount of heat
And pressure --

Too high a temperature
Would burn the wood.

Too much force would crack it.

These straight pieces of wood

Will become the rounded backs
Of windsor-style chairs,

Which is why this type
Of bending

Is called windsor bending.

Workers humidify the wood
In the steaming box

But will shape the pieces
Using a pressure-only process.

They mount what's called
A bending mold

Onto a hydraulic press.

This machine uses just pressure

To bend the wood
Around the mold.

No heat this time
To immediately set the shape.

Instead, once the press
Curves the pieces,

Workers hook up a chain
To temporarily hold the shape.

Then they transfer the bent
Pieces to a heated indoor dryer.

The drying process takes
Between two days and two weeks,

Depending, as before, on the
Type of wood and the dimensions.

Once the wood dries out,
The curve is permanent.

There are many wooden products
That require bent components --

This wheel for a horse-drawn
Carriage, for example.

Back to the windsor chairs, now.

A dowel machine rounds off
The bent pieces.

Before shipping the pieces out,

Workers run them
Through a sander.

This prepares them
For the furniture factories,

Who will varnish or stain them.

Upon receiving
These chairbacks,

The furniture factories
Will assembled them

To the straight parts
Of the windsor chairs.

Narrator:
The term "Membrane switches"
Probably means nothing to you,

But chances are you use them or
At least see them in use daily.

Membrane switches
Are those soft touch-pad buttons

On the controls
Of many electrical

And electronic devices --

For example, the buttons
On a microwave oven

Or on a cash register.

The surface of the appliance's
Control panel

Is called the graphic overlay.

It's a sheet of plastic

On which they print the design
Of the control buttons.

Each button has
A membrane switch underneath it.

To make this graphic overlay,

They first laser-print
A sheet of acetate film

With the design --
As many copies as will fit.

They lay the film
On a polyester screen

Coated with a light-sensitive
Chemical.

Then, using this machine,

They expose the screen to 2,000
Watts of ultraviolet light

For up to six minutes.

The light hardens the chemical
On the parts of the screen

That aren't shielded
By the design on the acetate.

This blocks the screen's minute
Holes everywhere

Except in the design.

Workers remove the acetate film

And rinse off the shielded
Chemical that didn't harden.

Now they have a screen stencil
Of the design

They're going to print.

Workers dry off the screen and
Install it on a printing press.

A squeegee drags the ink
Across the screen,

Pushing it down
Through the open holes,

Printing the design
Onto the overlay plastic.

Ultraviolet lamps cure the ink
In a matter of seconds.

Each color of the design
Goes on separately.

That means that there isn't
One printing screen

For the entire graphic overlay,

But rather a separate screen
For each color.

Meanwhile, on another screen
Printing press,

They print the circuitry layout
Onto transparent plastic.

The ink contains silver,
Which conducts electricity.

This circuitry layout will go
Behind the graphic overlay.

Again, they print several
At a time.

Once the printing's done,
It's time to assemble the layers

That make up
The membrane switch.

First, the circuit layer goes
Onto an adhesive sheet.

A roller insures a solid,
Airtight bond.

This spacer sheet will separate
The overlay and circuit layer

To prevent contact between
The two from being continuous.

Over each circuit goes a dome

Made of nickel-plated
Stainless steel.

This forms an electrical contact
Over the circuit

That must be forcibly pressed in
Order to activate the circuit.

They adhere a polyester sheet to
Hold the domes in place for now.

After cutting out each circuitry
Layout and each graphic overlay,

They expose the adhesive backing
On the overlay

And stick it
To the circuit layer.

The membrane switches
Are now complete.

This control panel
Is for a hospital bed.

Some membrane switches have a
Light-emitting diode, or l.E.D.,

A tiny colored light
That goes on

When you press the switch
To confirm contact.

The factory's robotic machines
Deposit two drops of epoxy paste

On the circuit layer
Wherever an l.E.D. Will go.

The paste contains silver --
Again, to conduct the current.

A robot then picks up
The l.E.D.S

And deposits them
On the drops of paste.

The robot then puts a dome
On each circuit,

Creating an electrical contact.

The red light you see is a
Camera checking the positioning.

Testing equipment runs a current
Through the circuitry

To make sure
That everything works.

Then a drop of transparent
Sealant goes over each l.E.D.

The sealant hardens
Under ultraviolet light,

Holding everything solidly
In place.

Now workers remove the panel
From the automated line

And plug it in.

Lighting up all the l.E.D.S

Helps them position
The graphic overlay properly.

This control panel
Is for a wall oven.

No l.E.D.S on this model.

And instead of a dome
Behind each button,

They print an electrical contact

Using the same conductive
Silver ink

They use to print
All the circuitry.

After rolling on
The graphic overlay,

They peel off
The protective plastic,

Then flip the control panel
Upside down

And snap it into its cover.

--captions by vitac--
Www.Vitac.Com

Captions paid for by
Discovery communications, inc.

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