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Modern Marvels: The Fascinating Story of Welding in America (S13, E16) | Full Episode | History — Transcript

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0:01NARRATOR: It arcs, explodes and blisters steel.
0:06It's used to make 50% of all products,
0:09and it puts the power to build a skyscraper in a man's hands.
0:13By friction or robot, even under water, these are the tools
0:18that the world can't live without.
0:21Now Welding on "Modern Marvels."
0:39Las Vegas, Nevada.
0:42Perhaps nowhere else in the world
0:44does the old come down as spectacularly
0:51and the new rise up as quickly.
0:54Right now you're in the east wing of the new Palazzo Hotel.
0:58We're on the 38th floor area, laying deck.
1:04NARRATOR: The Palazzo hotel will be the central hub
1:06of the world's largest resort, hotel and casino complex.
1:10And without the power of welding, it couldn't be built.
1:14Armed with high power welding guns and with nothing
1:18more than a safety harness between them and the ground
1:20below, these ironworkers will weld a quantity of steel
1:25nearly equal to the amount in the Brooklyn Bridge,
1:27Statue of Liberty and Empire State Building combined.
1:31There's just shy of 70,000 tons of [inaudible]..
1:37NARRATOR: Adrenaline runs high for welders working
1:40at such heights, and with so much electricity in use,
1:47the dangers are real.
1:50This particular machine runs on 483 phase.
1:53It's fed with 200 amps.
1:55At 480, if you make a mistake, you're not here tomorrow.
1:58It's almost instantaneous death.
2:03NARRATOR: By definition, welding joins two separate pieces
2:07of material through high energy.
2:10No other joining method forms a more direct and powerful bond.
2:14All the other methods, whether it's rivets,
2:17whether it's bolts, even if it's glues and adhesives,
2:21you wind up putting in extra material
2:24in order to make the connection.
2:25In the case of welding connections,
2:27bring the two pieces together, put a weld in between.
2:31It's a very efficient way of joining material.
2:35NARRATOR: But efficiency is only half the story.
2:38Because welding creates a bond along a seam or joint,
2:41it is nearly always stronger than the base metals
2:44used to form it.
2:45The tensile strength of the welded material
2:47itself is actually greater than the material you're welding.
2:50A good weld, the material itself will tear before the weld will
2:53tear.
2:55NARRATOR: The source of this strength
2:56is more than just surface deep and goes right down
3:00to the steel's very atoms.
3:02Every atom within a beam possesses
3:04electrons that encircle it in what is called an electron
3:07cloud.
3:09When a welder applies intense heat,
3:11the atoms are slammed together so forcefully
3:14that they begin to share a single, united electron cloud.
3:19Now locked as one, these new molecules are more powerful
3:22together than separate.
3:27For many centuries, the only way to make these welded bonds
3:30was with furnace and hammer, a process now known
3:33as forge welding.
3:34With forge welding, two pieces of material
3:37are put lapped over each other, heated not
3:41to the point of melting but until they're hot,
3:43and then hammered together.
3:45That hammering together of the two metals
3:47will achieve the same metallic bonds that today we
3:51form with an electric arc.
3:54NARRATOR: Today, electricity has replaced the brute force
3:56of the forger's hammer to construct our world
3:59from the car you drive to the plane you fly and everywhere
4:04in between.
4:05The most common method is known as electric arc welding, which
4:09is based on principles first discovered
4:10at the turn of the 19th century.
4:15Those principles revealed that electric current will jump
4:18the gap between two nearby metal conductors
4:21to form a completed electrical circuit.
4:25This jump, known as an electric arc,
4:28generates a spark-like discharge that is both extremely bright
4:31and intensely hot.
4:34The arc is estimated to be between 6,000 and 8,000 degrees
4:39Fahrenheit.
4:40That's the same temperature as the sun.
4:42Steel melts in and around 3,000 degrees, so this 6,000 to 8,000
4:49degree arc is more than ample heat to melt the steel
4:52that we're joining.
4:55NARRATOR: By the 1890s, engineers
4:57had harnessed this intense, newfound energy to create
5:00the first electric arc welds.
5:04A work lead or ground was attached to one corner
5:07of the metal to be welded.
5:08Electric current then flowed from a generator
5:11through a long conductive metal stick known as an electrode.
5:15As the stick neared the grounded metal,
5:17an electric arc was formed, causing heat to melt the metal.
5:22The apparatus was crude but the basics were sound and are now
5:26reflected in the simplest arc welding
5:28form in use today, stick welding.
5:31The basics of the process are, you have an electrode holder,
5:37you have a cable that runs back to the machine to pick up
5:40the welding current, and you place the bare end
5:42of the electrode in the holder, and it picks up
5:45electrical contact there, conducts current down
5:48to the end of the electrode, which is bare.
5:50The technique is touching the electorate against the work
5:53and then moving it far enough away to establish an arc
5:56but not so far it goes out.
5:58And if you leave it too close, it'll stick.
6:01You pull away too far, it'll go out,
6:02so the trick is to get your bounce where it's just
6:05about right.
6:07NARRATOR: When the arc is struck and positioned near the metal
6:10pieces, the intense heat causes both the electrode
6:13and the metal along the seam to melt together
6:16into what is called the puddle.
6:19Until it hardens, this molten puddle
6:22must be protected even from the very air that we breathe.
6:27The air we breathe is about 80% nitrogen and about 19%
6:33oxygen. It's really good for breathing but it's not
6:36good for liquid metal.
6:38And just like we dissolve sugar in hot coffee,
6:41these gases dissolve in liquid metal.
6:45When the metal solidifies, the gas percolates out
6:50and that make holes in the weld.
6:53NARRATOR: The dangerous result could be a weak, even brittle
6:56weld, so to shield the puddle, a chemical coating
6:59is applied to the electrode.
7:03As it melts under the heat of the arc,
7:05this chemical coating dissolves into shielding gases
7:08that envelop and protect the weld, keeping it free of air.
7:13This is known as shielded metal arc welding,
7:16and as the technology evolved, the coating
7:19took on even greater significance.
7:22The chemical coating has three functions.
7:24Some of the coating forms shielding gases
7:26at the heat of the arc that protect
7:27the weld from the atmosphere, some of the chemicals
7:31at the heat of that arc form a liquid slag which protects
7:33the weld as the shielding gases move along,
7:36and some of the elements are alloyed into the deposit
7:38to make a high strength deposit.
7:40So three things happened while you're
7:42moving this arc along the work.
7:45NARRATOR: When the weld is complete and is cooled,
7:48the slag is chipped away to reveal
7:50the trail of welded metal known as the bead.
7:55Getting the proper length, depth and form
7:57of the puddle along the bead takes years of practice.
8:02There's so many variables when you weld.
8:04There's very few times that two things you weld together
8:07are the same.
8:08Either the metal changes, the thickness
8:10of metal, the environment you're in, the conditions
8:13the metal is used for-- there's just so many things change
8:17that you have to know a lot of different things about welding.
8:21NARRATOR: Complicating matters are the safety requirements,
8:24beginning with a welder's mask.
8:26Just as staring into the sun can damage your eyes,
8:29so too can an electric arc.
8:31Therefore, protection is crucial.
8:33When you first flip it down, it's dark.
8:35You can't see anything, but you quickly get comfortable
8:37with it.
8:39Once you strike the arc, it's like a big flashlight.
8:40You can see what you're doing.
8:44NARRATOR: Although electric arc welding was first
8:46discovered in the 1800s, its acceptance was slow in coming.
8:51Anything new, they fight.
8:53It wasn't thoroughly accepted so it took time
8:56to make the transition into the welding process.
9:00NARRATOR: No company was more influential in changing
9:03the tide than Lincoln Electric Company of Cleveland, Ohio.
9:07Today, Lincoln Electric is the largest manufacturer of welding
9:11equipment and consumables in the world.
9:15That success is rooted in Lincoln's commitment
9:17to proving the viability of welding,
9:20even in the face of constant doubters.
9:24And no industry was initially more skeptical than the biggest
9:27one of all, building construction,
9:30where rivets were king well into the 1940s.
9:34Rivets were intuitive.
9:37If you think about it, putting in something
9:39with a head on either side, that makes sense.
9:42Welding had some mystery about it.
9:46NARRATOR: But riveting was also extremely difficult work.
9:49It required fabricators to hole-punch the steel beams.
9:53Then a team of workers aligned those holes
9:55to their exact counterpart.
9:57Rivets were heated in a central oven then hurled
10:00to the proper joint.
10:02He would hit the rivets, and once they got heated,
10:05he would throw them to the person who was actually
10:07standing at the point waiting for the first rivet.
10:10So you had a pitcher, a catcher with a set of tongs who would
10:14slide it into the hole, and then you had a guy with a bucket,
10:17and then you had a riveter.
10:18And the riveter would round the head on the opposite side.
10:22NARRATOR: Significantly, rivets limited the design options
10:25for architects and building engineers.
10:29A lot of very famous and beautiful work
10:32is done with rivets, but basically, you're
10:34building a box with a design to the inside of the box.
10:37You can only carry so much shear on that connection.
10:41NARRATOR: In 1928, Lincoln Electric
10:44joined with a local architectural firm
10:46to erect the first commercial building wholly constructed
10:48from arc-welded steel.
10:51In the upper Carnegie Building, the typical dense network
10:55of riveted steel was replaced by a series of continuously welded
10:59beams that ran the entire length and height of the building.
11:03Not only did welding free up space,
11:06but these continuous beams carried even greater loads
11:08and stresses than their riveted counterparts.
11:12Connection's always the weak point in a structure.
11:17Connecting things together is always a challenge,
11:21but welding changed all that.
11:23Literally, if you could get the material in the configuration
11:26you wanted it, there was a way to weld it together.
11:30NARRATOR: Today's skyscrapers come in many shapes and sizes
11:33in large part because continuous beams can be fabricated
11:36and welded into curves and unique angles.
11:41To construct these beams, welders
11:43will make 30 to 40 passes on the crucial joints,
11:46using Lincoln Electric's latest flux-core welding technology.
11:52Here, the traditional stick electrode
11:54has been replaced by wire on a roll that feeds directly
11:57into the welder's gun.
12:00The chemical flux that protects the weld from the air
12:03is now contained within the wire itself
12:05and melts just as before.
12:07There's approximately 90 tons of weld wire that
12:11will be used and consumed in this project alone.
12:14That's somewhere around 180 million inches or 2,800 miles
12:20of weld wire.
12:21You could stretch a single wire from LA to New York
12:24and have leftover.
12:26NARRATOR: On the largest beams, which
12:28can weigh as much as 900 pounds per linear foot,
12:31a team of welders can work on a single weld for hours.
12:36The columns that we're looking at right now
12:38are basically supporting the entire east wing of this tower.
12:41Originally, these pieces were so long,
12:44the capacity of the cranes would not pick them up and set them,
12:48so we had to cut them down, make them lighter so the crane could
12:51set them.
12:53And the engineers wouldn't allow us
12:54to make that a bolt and splice.
12:56It had to become a welded splice.
12:58It's about a 30-hour weld.
12:59I believe we had two guys working on that simultaneously
13:03for 30 hours of welding.
13:09Welding really enabled the architect, the engineer,
13:13to dream bigger dreams, make bigger bridges
13:15and make taller skyscrapers, and to do so
13:18in a reliable and dependable way.
13:21NARRATOR: But at the end of the day,
13:24those big dreams are only as solid as the ironworkers who
13:27weld them together.
13:29We're not presidents.
13:30We don't get monuments built to us,
13:31but when you look across the skyline,
13:34ironworkers have changed the way that looks.
13:37NARRATOR: But electric arcs aren't the only way
13:39to make a weld.
13:40In fact, others are a real blast.
13:50Pennsylvania's Allegheny mountains,
13:53birthplace of American steel.
13:56Here in the hillsides that surround historic mill towns,
14:00the most powerful welding process of all
14:02occurs more than half a mile underground.
14:05Fire in the hole.
14:06[explosion]
14:11NARRATOR: It's called explosion welding,
14:18and with a force measured in millions of pounds
14:20per square inch, explosion welding does what
14:23no other welding method can--
14:26join nearly every kind of metal together, no matter the type
14:30or composition.
14:32Explosion welding allows highly similar metals
14:35such as aluminum, carbon steel, alloy steel, stainless steel,
14:39alloys of copper--
14:41all can be welded to one another.
14:44NARRATOR: The result, a single welded piece known as clad
14:48that combines the best characteristics of each metal
14:50involved.
14:53Wherever there is high heat, intense pressure or corrosive
14:57liquids and gases, clad is probably there.
15:02It could be a column, it could be a heat exchanger,
15:04it could be a horizontal tank, but when
15:06you see a chemical complex or an oil refinery,
15:09there will be a lot of clad metal in there.
15:13NARRATOR: To create an explosion weld, two large pieces of metal
15:16are stacked atop one another, then covered
15:20with a high-powered explosive.
15:30When detonated, the downward force of the explosion
15:32welds the two pieces together through a combination
15:35of intense force and remarkable physics.
15:38What you can see here, and it's very clear,
15:40you have two different materials.
15:42Stainless steel is a darker gray, a lighter
15:45gray for the carbon steel material.
15:47The detonation was initiated at this point
15:50and you can see the deformation from our initiator.
15:53That starts the explosion and the explosion
15:56rolls across the entire top surface of the plate,
15:59zipping the two together.
16:06NARRATOR: No one would have ever thought such a violent process
16:08could be controlled and mastered had it not
16:11been for the devastation and havoc of World War
16:13I and later WWII.
16:17The origin of explosion welding
16:19was first observed during the First World War
16:22when shrapnel may have stuck to armament.
16:25It wasn't just stuck but it was actually welded.
16:30NARRATOR: There was only one possible explanation,
16:33the explosive force these metal pieces had endured.
16:36It was an observed phenomenon that was later
16:39duplicated in the laboratories and practiced commercially.
16:45NARRATOR: Today, Dynamics Materials Corporation
16:47is a world leader in explosion welding technology.
16:51Here, the decades old discoveries
16:53from the battlefield have been refined into an exacting
16:55science.
16:59The explosion welding process begins as soon as the two metal
17:02plates arrive at DMC's main plant outside of Pittsburgh,
17:06Pennsylvania.
17:09To maximize the welding course of the explosion,
17:11the surfaces of each plate are ground as uniformly flat
17:14as possible, a process that also removes any rust, oxides
17:19and other surface flaws.
17:23They're then ready to be assembled into the pack, which
17:26locks the plates into position for the explosion.
17:30To build a pack, the stronger and thicker of the two plates
17:33is laid face up.
17:35From now on, this plate will be identified as the backer.
17:39Small metal spacers of equal height
17:41then tacked onto the surface of the backer in a uniform grid.
17:45These spacers will maintain a set gap
17:47between the backer and the second plate
17:49which is placed on top.
17:51The second plate is thinner than the backer
17:54and is called the cladder.
17:57The stand-off gap between the backer and cladder
18:00is less than an inch in height, yet without it, the explosion
18:04weld would be impossible.
18:07In the final stage of assembling the pack,
18:09a folding wooden frame is constructed
18:11along the edges of the cladder.
18:14When this frame is later unfolded
18:16inside the underground explosion chamber,
18:19it serves as the bed for the explosive powder that
18:22is poured on top.
18:24The three essential variables of an explosion weld are first,
18:29the stand-off gap.
18:31The spacing between the two metals
18:33needs to be very tightly controlled to ensure
18:37the highest quality weld.
18:38The second two parameters deal with the explosive.
18:41One is the velocity of the explosive,
18:44the speed at which it burns, and the height
18:48of the bed or the quantity of explosive which is evenly
18:51spread on the top plate.
18:54NARRATOR: The explosive powder is a proprietary blend
18:57of common and unique explosive chemicals.
19:01The amount and exact formulation is always matched
19:03to the types of metal involved.
19:10Once the pack is set, everyone evacuates the chamber
19:14except the blaster in charge, who
19:16remains to wire the detonator.
19:19He will be the last to leave the chamber.
19:23After all personnel are accounted for,
19:25the blaster connects his initiator switch
19:27to the detonator wires and fires the explosion.
19:32Fire in the hole.
19:34NARRATOR: The explosion is detonated from one edge
19:37of the cladder and moves across the upper level
19:39of the pack at a uniform speed.
19:43This explosive front progressively
19:45drives the cladder plate downward toward the backer
19:48at the slight collusion angle caused by the stand-off gap.
19:53Forward of the collision point, air is forced out
19:55of the gap at high velocity.
19:58All oxides and impurities are expelled, rendering the plate
20:01surfaces metallurgically pure and ideal for a weld.
20:06As the backer and cladder collide,
20:08the weld is created nearly instantaneously
20:10across the entire surface of the plate.
20:17Because of the intense dust created by the explosion,
20:20workers can't retrieve the newly formed clad from the explosion
20:23chamber for more than 18 hours.
20:28Not surprisingly, the power of the explosion
20:30can cause significant deformation
20:32to the newly formed clad.
20:35Therefore, upon its return to DMC central processing
20:38facility, the clad undergoes a final series of corrections.
20:48These include heating the clad in an oven that causes
20:51the metals to soften slightly.
20:54This relieves stress from the blunt force of the explosion's
20:56impact.
20:59Any bowing or misshapen curves are flattened out
21:02by either a three million pound press, or for thinner clads,
21:07by a series of rollers known as levelers.
21:12Finally, before the material is shipped,
21:15stringent testing is conducted to ensure a solid weld
21:18between the two plates.
21:21There's a lot of testing because generally, these metals
21:24will go into a very high pressure vessel.
21:27The stakes are extremely high if there's a failure,
21:30ao the owners of big plants and chemical manufacturing and oil
21:35refineries are extremely concerned that their materials
21:39are what they ordered and specified.
21:42There's really no room for error.
21:45NARRATOR: Once the material has been proven
21:46to meet exacting specs, it's ready to be shipped
21:49to the customer.
21:54But explosion welding isn't the only adventurous business,
21:57and may look downright tame compared to welding 325 feet
22:03below the ocean's surface.
22:09It's a rule that defines common sense.
22:11Don't mix water with electricity.
22:13It can kill you.
22:16But there is a rare breed of experts
22:17who dare to swim against convention
22:20and perform a job that most consider downright crazy.
22:26Underwater diver welders thrive on the dangers of the deep
22:31where visibility can be zero and deadly hazards the norm.
22:35Why?
22:37To perform the perfect weld.
22:39You're under water and playing with electricity.
22:41It doesn't seem like a good combination
22:43but it works quite well.
22:47NARRATOR: Over the last 30 years,
22:48the ocean depths have become vast job sites for the energy
22:52and communication industries.
22:54This encompasses everything from pipelines to platforms
22:58to subsea wells to inspection, repair and maintenance.
23:03We're working in water depths up to 10,000 feet.
23:08NARRATOR: Global Industries is a leader
23:10in offshore construction, engineering and support
23:13for the oil and gas industries around the world,
23:17and to meet this constant demand,
23:19Global Industries requires their welding teams
23:21to undergo years of specialized training for all types
23:25of offshore environments.
23:30We're here at our research and development training center
23:34here in New Iberia, Louisiana.
23:36We're dressing out our dive now to getting
23:38ready to get into the tank and do some training, do
23:41some welding.
23:43NARRATOR: There are two basic forms of underwater welding,
23:46wet welding and dry welding.
23:51Wet welds are the most common and can be shielded metal arc
23:55or stick welds made by a fully submerged diver
23:58welder in a wetsuit.
24:01The electrode is waterproof and inserted into an electrically
24:04charged rubber-encased stinger.
24:09Once struck, the electric arc burns just as
24:12if it were on dry land since water is equally conductive.
24:17Likewise, the electrode's unique waterproof coating
24:20shields the weld from water contamination.
24:24But in case you're wondering, his rubber gloves
24:27are the only things that stand between the diver
24:29welder and electric shock.
24:32You have a hole in that glove, then
24:34you grab a hold of that live stinger,
24:36and that will give you a real good one
24:39and you'll taste your fillings in your mouth.
24:42NARRATOR: Fortunately, the odds of a fatal shock
24:44are slim because the welding equipment operates
24:47on DC current, which is far less dangerous than the ordinary AC
24:52current found in a typical home.
24:55Comm check, comm check.
24:57NARRATOR: To get the diver welder fully suited,
25:01two other diver welders act as his tenders,
25:04checking and testing every piece of equipment, including
25:06the helmet.
25:08Not only does the helmet provide air for the diver welder
25:10to breathe, it also serves as a full welding mask,
25:14protecting his eyes from the intense arclight.
25:18Right here we have the lens plate, the face lens
25:21that a diver will flip down when he's ready to start welding.
25:25He'll flip it up when he's finished welding
25:27and take a look and see what he's doing.
25:30NARRATOR: After the diver welder is suited up,
25:32he carefully enters the water and makes his way
25:34to the bottom of the tank.
25:38From the moment he puts on his helmet,
25:40the diver welder is in constant communication with the control
25:43room via audio links and a video feed.
25:46Comm check, one, two, three.
25:48How do you got me, John?
25:49JOHN (VOICEOVER): Four, five, six.
25:51Loud and clear.
25:52All right, set up the weld.
25:53Roger, setting up.
25:57NARRATOR: The trainee must not only
25:58learn to strike and maintain an arc,
26:01but he must also be able to connect and reset
26:03all of his equipment, including the electrode.
26:07Once in the water, the electrode is inserted into the stinger,
26:11which is termed cold because the control room has not yet
26:14turned on the electricity.
26:17When the diver is ready to weld, he requests that the current
26:20be turned on.
26:20[inaudible].
26:21Make it hot.
26:23Roger.
26:24Making it hot.
26:27NARRATOR: Like every surface welder,
26:29the diver welder must be a master of concentration
26:32and stability.
26:35You're going to have a lot of things that can interfere
26:38with what you're doing when you're welding.
26:40Just the surge of the ocean can push you around.
26:43Some divers like to actually put their hands up, hold the rod
26:47itself, because it gives you a lot of feel on it.
26:50If you just have the rod way back here
26:54from where you're working, you don't have the feel
26:57that you need.
26:59NARRATOR: Even fish can become distracting and potentially
27:02dangerous obstacles.
27:04Barracuda like to watch.
27:06It's a giant fish.
27:07It looks like a torpedo with nasty teeth
27:10that stick out everywhere, and they like just kind of hover
27:13over your shoulder to see what you're doing all the time.
27:16And you're just kind of like, what's-- ah!
27:18But they're doing their own thing.
27:23NARRATOR: But sometimes a job requires a diver welder
27:26to go to extreme depths and stay in that environment for days,
27:30even weeks.
27:32This is called saturation diving and requires serious courage.
27:38It may also require the highly sophisticated technologies
27:42of dry underwater welding.
27:46The difference between wet and dry underwater welding,
27:50the dry underwater weld will require a habitat.
27:54A habitat is lowered down and put in place
27:57on the member on the pipeline that's going to be repaired.
28:01Once it's installed, they seal it
28:04and then they actually put the air down to it
28:06and pump all the water out of it.
28:09This allows that piece to be basically dry now,
28:13and so the divers can go down, and they'll actually
28:16climb up inside the habitat, remove their helmets
28:20and actually be able to go to work and weld
28:23that particular item in the dry.
28:28NARRATOR: Dry underwater diver welders
28:30work in pairs and in six to eight hour shifts.
28:37When done, they return to the surface in a diving bell,
28:41then enter a second habitat maintained aboard ship.
28:45Within these ownership habitats, they
28:47will eat, sleep, and relax before returning to the ocean
28:50floor.
28:53Both the diving bell and on ship habitat
28:55maintain the same pressure as if the divers were still
28:581,000 feet under water.
29:02This is the only efficient and practical way for their bodies
29:05to remain adjusted to such extreme pressures.
29:08Otherwise, the diver welders may experience the bends
29:12and other physical perils, even death.
29:16To prepare diver welders for these conditions,
29:19Global Industries has built an unparalleled underwater
29:22simulator.
29:24This facility that you see behind me right here,
29:26It's really the only one of its kind in the United States.
29:29We call this the dry pot.
29:32We can carry out dry welding scenarios down to 1,000 feet.
29:37NARRATOR: A hyperbaric chamber simulates the high pressures
29:39the human body must endure when working at great ocean depths.
29:45Akin to being an astronaut, the trainee will spend more than a
29:49week living in this simulated environment,
29:52and conditions are tight.
29:55It's very, very cramped inside there.
29:58There's a place for everything to go
30:00and you have to be sure that you put everything in its place
30:03before you go in and start doing things,
30:05because there are a lot of things that can bite you
30:08in there.
30:11NARRATOR: Unlike the wet welder, the dry welder
30:14can perform more than stick welds in his cramped habitat.
30:18I'm standing right in front of the entrance
30:20to the dry pot hatch.
30:22Royce is doing gas tungsten arc welding.
30:24It's also known as TIG welding, which is our word for Tungsten
30:28Inert Gas.
30:30NARRATOR: Once his training is finished,
30:33the trainee enters this decompression chamber
30:36to slowly acclimate his body back to the normal atmosphere.
30:41But while even these adrenaline junkies
30:43need to rest once in a while, some welders never
30:46take a break.
30:48Of course, they're robots.
30:55Welding, the heart and soul of making a car,
30:59and for major automobile manufacturers
31:01like General Motors, no process is more vital
31:07or more automated.
31:09When I first started with General Motors,
31:12there weren't any robots in the body shop I worked in.
31:15Two years later, there were 40 of them.
31:17In the body shop we're standing in now,
31:19there's approximately 1,200 robots.
31:22Over a third of them, 480-some, are welding robots.
31:28NARRATOR: Here at GM's Lake Orion assembly plant,
31:31more than 16,000 cars roll off the lines every month.
31:35By the time each car is fully assembled,
31:38it will contain thousands of welds.
31:43On this structure as it sits right here,
31:45there's approximately 3,800 welds.
31:48Once the outer structure goes down,
31:50there will be approximately 1,200 more welds
31:51added to it for approximately 5,000 welds
31:54overall on the vehicle.
31:57NARRATOR: Nearly all those welds are completed
31:59by robotic welding systems which load, position and weld
32:08more than 240 component parts.
32:12Most of the robots that are used for welding
32:14are actually used for spot welding,
32:16and probably 60% of the welding robots that are out
32:20there are actually spot welding robots.
32:23NARRATOR: Unlike arc welding, spot welding does not
32:25create a bead, nor is it designed for heavy steel items
32:29like beams.
32:31Instead, spot welds bond thin metal sheets
32:34as in car doors or hoods.
32:38Energy is focused to a single spot
32:40where two electrodes make direct contact with the metal sheets
32:43to be joined.
32:44The electrodes are made of copper
32:46because it has low electrical resistance
32:49and high thermal conductivity.
32:51This means it can deliver some serious juice.
32:55This particular unit is a pneumatic operated spot welding
32:58system.
32:59It's got a 75 kVA transformer back here.
33:02The electrodes up here are all water-cooled.
33:05This particular setup here probably
33:07runs about 10,000 to 12,000 amps through these electrodes
33:10right here.
33:11It's not uncommon to see 40,000, 50,000 amps run
33:14through the electrodes.
33:15NARRATOR: Given that most houses run on less than 200 amps,
33:19that's a lot of power, but it's not the only factor
33:22in a reliable spot weld.
33:24You need pressure.
33:27When the two electrodes come together,
33:29they pinch the two metal sheets at the spot
33:32and cause a small indentation in both.
33:37Electric current then begins to pass
33:39from one electrode to the other through this spot in the sheet
33:42metal.
33:44As it does so, the current that flowed so smoothly
33:47through the copper now encounters resistance
33:50in the less conductive metal pieces.
33:52This resistance results in heat and the metal
33:55begins to melt causing a molten nugget to form.
33:59When the molten nugget cools and coalesces,
34:01it locks the two metal sheets together.
34:05The electrodes then release the pinxh point and move on.
34:09A robot can make a series of spot welds
34:11in a relatively short period of time.
34:13For a man, it's a heavier task.
34:16A typical spot welding gun might weigh anywhere
34:19from 100 pounds to 200 pounds.
34:21That's a lot of physical labor to move a spot welding gun,
34:25and so a robot that's designed to handle that kind of weight
34:29is an ideal setup, because the robot can just handle the spot
34:32welding gun and consistently put it in the same place
34:35every time.
34:37NARRATOR: Factor in the sheer number of spot welds
34:39required to assemble a car, and robots
34:41make an incredibly practical solution for car manufacturers.
34:47And advances in recent technology
34:49allow robots to reach further, work closer together
34:53and execute a greater variety of welds than ever before.
34:58The robot can pretty much weld at the same speed as a man.
35:02Where the payoff is is that a robot is always welding.
35:07A man has to weld, and then lift his hood up and adjust the part
35:13and put the hood back down and reweld again, Where the robot's
35:18just going to weld, weld, weld.
35:21It might have an 85% arc time compared to a manual of 20%.
35:27It took a man about three hours
35:29to make this particular product.
35:31Now that the robot's welding it, it
35:33takes essentially about a half an hour
35:35to weld the entire part.
35:42NARRATOR: But today, robots aren't just spot welders.
35:46Here at Robot Works, a leader in robot system integration,
35:50robots execute nearly every form of welding,
35:54and often in surprising ways.
35:59This system has the capability of running at about 30 to 40
36:02inches per minute of weld.
36:04This system is unique in that there's two technologies that
36:06are actually integrated into it, one called touch sensing,
36:09another called seam tracking.
36:11What touch sensing allows the robot to do
36:13is actually find the seam.
36:15It would come down, sense that it has touched the part in one
36:18specific spot, record that data, save that positional data.
36:23It would then come up, sense the next spot
36:25doing the same process, and at that point in time,
36:28the robot would know from the trigonometry
36:30where that seam starts.
36:32There is another technology called seam tracking.
36:35What that allows you to do is once the robot has found
36:37the seam, it actually allows the robot to stay within the seam
36:40throughout the course of the weld.
36:46NARRATOR: But even as robots become
36:47more sophisticated and commonplace,
36:50they will still require HMI, Human-Machine Interface.
36:55After all, someone still needs to program them,
36:58and he or she better know welding.
37:00For the programmer, we always suggest to take a guy
37:03that's a good welder, because he's going to know like if he
37:07hears an arc and it's not right, he'll know that it might be
37:10because of the shielding gas, or the stick-out the robot's using
37:15because he just knows welding.
37:16But a guy that doesn't know welding
37:18might think it's because of the robot controller or something
37:21to do with the robot.
37:22Somebody that understands the process
37:25is the best kind of a robot operator programmer.
37:29NARRATOR: Think robots are innovative?
37:32Well, you haven't seen, or should we
37:34say, you haven't heard, anything yet.
37:44Say welding and you immediately think iron, steel,
37:48metal on metal.
37:50But today you can weld just about anything, including
37:53plastic.
37:54Plastic toys, plastic packaging and lots of household items
37:58are welded together by a process known as friction welding.
38:04Friction welding comes in many forms.
38:07It all work essentially the same.
38:10They generate heat through mechanical action
38:12like the high speed rubbing of two sticks together.
38:16With plastics, the best friction welds
38:19are made through the power of sound.
38:22It's called ultrasonics.
38:24Ultrasonics utilizes the high intensity acoustic energy
38:28that occurs in frequencies beyond human hearing.
38:32The sound waves cause the plastic pieces
38:34to literally vibrate against one another at high intensities.
38:39At that interface, heat is generated and the two pieces
38:43fuse together.
38:44It happens so fast that the naked eye can't see it.
38:50People don't realize the amount of power that
38:53is available in sound waves if the sound waves are focused
38:58properly, and these materials are vibrating, in many cases,
39:0320,000 times per second, 40,000 times per second.
39:06That frictional heat is so intense
39:11that the plastic welds within a fraction of a second.
39:18NARRATOR: In 1964, Roberts Soloff
39:21received the first ever patent for ultrasonic plastic welding.
39:26Today his company, Sonics & Materials,
39:29builds the technology that welds everything from toothpaste
39:32tubes to coffee makers to simple toys.
39:37At their headquarters in Newtown, Connecticut,
39:40ultrasonic welding machines are manufactured
39:42to precise specifications, or else the welds
39:45wouldn't be perfect.
39:48There are four main parts in an ultrasonic welder, a power
39:52supply and three components known as the ultrasonic stack.
39:57This is the ultrasonic stack for the ultrasonic welding
40:00press, which is comprised of the ultrasonic converter,
40:04the booster and the ultrasonic horn.
40:07NARRATOR: The power supply takes standard 60 hertz power
40:11and pumps it up to 20,000 hertz of acoustic energy.
40:14This acoustic energy causes coin-sized ceramic disks
40:18within the converter to physically expand and contract,
40:22creating 20,000 mechanical vibrations per second.
40:26These vibrations are then focused to the plastic parts,
40:29first through the booster then through the horn, which
40:32delivers the vibrations directly onto the plastic parts
40:35to be welded.
40:38Although sparks don't fly during ultrasonic welding,
40:41it still gets the job done.
40:44This happens to be a two-piece whistle.
40:47So we take the two pieces of plastic.
40:49We put them in a lower fixture.
40:51The fixture is made to the application,
40:54to the piece of plastic, and then we
40:56have a very basic, flat-faced ultrasonic horn
40:58because the part is flat.
41:00There's no contours to the part.
41:04So that quickly, we just welded the two pieces of plastic
41:07together in 0.24 seconds.
41:13What I'm to do is take a screwdriver
41:16and break the plastic apart right at the weld area.
41:21And in turn, this will show the molten white plastic where
41:25it bonded to the red plastic.
41:28NARRATOR: And think ultrasonic for the hermetic seal
41:31on clear plastic packaging--
41:34you know, the plastic you can never quite get open?
41:37We have these PVC clamshells or tamperproof clamshells
41:40so that the product can't be easily removed from it
41:43or put in a pocket.
41:44Ultrasonics is commonly used to seal these clam shells.
41:52And now we have ultrasonically welded
41:55the edge of the clamshell.
42:00NARRATOR: While ultrasonics occurs in the wink of an eye,
42:03another form of friction welding will keep your head spinning.
42:06Spin welding is rotary friction under pressure, which
42:10generates heat in the joint area to melt the plastic
42:13and fuse the parts together.
42:18NARRATOR: A typical insulated coffee mug
42:20is spin welded from two parts.
42:24A suction device grabs hold of the inner shell
42:27and rotates as it descends into the outer shell.
42:31The collision of the stationary and rotating pieces
42:34generates heat, causing the plastics to soften.
42:39When a braking system stops the rotation,
42:41the softened plastic seams of the two shells
42:43fuse as they cool.
42:48The result?
42:49A perfect hermetic seal.
42:52So from ordinary household items to structures
42:56of extraordinary heights and depths,
42:59welding plays a crucial role in everyday life
43:03by simply joining the world together.

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