A RIVETING TALE

How will Ford build the aluminum F-150?

Aluminum bodies move down the line at the Solihull plant, top. Rivet guns, above left, take the place of spot welds. Above right, thin strips of adhesive are applied. A 2014 Range Rover uses 3,722 rivets and 187 yards of adhesive strip the width of a pencil.
INTERACTIVE
Solihull assembly plant
Location: Near Birmingham, in England's industrial Midlands
Opened: October 1940
First aluminum vehicle: 1948 Land Rover Series 1
Aluminum-bodied vehicles produced today: Land Rover Defender, Range Rover, Range Rover Sport
Planned: 2016 Jaguar XE compact sports sedan
Related Links
Related Topics

SOLIHULL, England -- The humble rivet.

That's what Demos Hoursoglou, Jaguar Land Rover's body-in-white manufacturing manager here, puts near the top of his list of worries about assembling the aluminum body of the Range Rover.

The 2014 Range Rover body uses 17 types of rivets, 3,722 per vehicle. If one jams in a gun or is inserted incorrectly, production stops.

Before a rivet reaches the production line, it is inspected at least twice, sorted and X-rayed. Each shipment of bar-coded rivets must be matched to the exact guns that will shoot them into the aluminum body parts.

So if you want a peek at the daunting manufacturing challenge awaiting Ford to assemble F-150s with aluminum bodies, you need to look at rivets -- and many other complex aspects of this assembly plant in England's industrial Midlands.

Manufacturing with aluminum is well understood; it's just complicated. Many more steps are jammed into the same amount of time it takes to make a steel body assembly.

Ford engineers say they aren't worried, because Ford largely devised the system when it owned Jaguar and Land Rover.

"Obviously, we did a lot of the advanced engineering work when Jaguar was part of the fold. And so we have a lot of experience," Raj Nair, Ford's group vice president of product development, told Automotive News in January.

But that won't make the task any easier this fall when Ford starts assembling about 650,000 F-150s per year at two plants. By contrast, Jaguar Land Rover assembles just 95,000 aluminum-bodied vehicles per year at Solihull.

Inside Solihull

187 yards of adhesive


Each Range Rover body has 403 separate components -- stampings and cast pieces that are held together with industrial adhesive and rivets.

At the start of the assembly line, stamped aluminum body panels and die cast parts are picked up by robot arms and placed in jigs or frames. The components are held in precise positions as the adhesive is applied.

"Rivets and glue are like having a set of pants with a zipper and buttons," says Mark White, Jaguar Land Rover's chief technical specialist for aluminum. "You don't actually need them both -- but if you've got both, basically, your pants are never going to fall down."

Each Range Rover body uses 187 yards of adhesive -- nearly two football fields in strips about the width of a pencil. Once the body is assembled, it goes to the paint shop where it is baked at 140 degrees C for 20 minutes to harden the adhesive.

Solihull stats
— World's largest aluminum body shop, at 312,000 square feet
— Length of body-in-white production line: 2,483 fee
— Scheduled 2014 production: 95,000 combined Range Rover and Range Rover Sport; separate line for low-volume Defenders
— Time 1 body-in-white spends in assembly: 10.1 hours
— Number of parts in a Range Rover body: 403
— Rivets in 1 Range Rover: 3,722
— Yards of adhesive in one Range Rover: 187, in strips about the width of a pencil
— 1 body completed: every 142 seconds
— Number of robots: 370
— Number of employees per shift: 177
— Percentage of recycled aluminum used per vehicle: up to 50%

Source: Jaguar Land Rover

Hoursoglou: 1 bad rivet stops line

But it's those rivets and the complexity of managing them that are the most critical aspect of body assembly, says Hoursoglou. Rivet guns shoot rivets through the metal to join the sections together. But these are not the pop rivets you buy at the hardware store. They are far more complex.

Some of the 17 different boron steel rivets, coated with a substance that prevents corrosion, look identical -- same width, same length, same shape -- but they differ in hardness.

Before a rivet gets to the Range Rover production line, it is X-rayed to ensure it is defect-free. The coating prevents galvanic corrosion between the steel and aluminum.

Because the task is so crucial, only four specially trained people per shift are authorized to handle the rivets. Each bag is scanned to ensure the rivets are matched to the proper gun.

Land Rover uses 3,722 rivets per vehicle. Ford isn't talking about F-150 details yet. But, using that same number of rivets per vehicle, Ford would use about 2.4 billion rivets per year to assemble 650,000 F-150s.

The Solihull plant uses 17 types of rivets; here are four of them.

Stronger than welds


Spot welding, used on virtually all steel bodies, is far simpler than riveting. Usually only the pressure, duration and the intensity of the weld varies. But assembly at Solihull involves 17 types of rivets, each selected for a different joining task.

"A spot weld gun is a spot weld gun, and providing it has access, you can do all the welding you need," says Hoursoglou.

Rivets are stronger than spot welds, so fewer are required for aluminum-bodied vehicles. The old steel Range Rover, discontinued in 2012, used more than 6,000 spot welds -- almost double the number of rivets that hold the Range Rover body together. But each of those rivets must be perfectly inserted.

"Working together with body engineering, we did a lot of work up front to understand every single rivet in every single position and how it performs and what it means from a manufacturing control point to deliver quality," said White.

Precise measurements are taken of each rivet that is punched through the Range Rover's body panels. Not only are the rivets checked for placement, but the force used to push them through the aluminum is monitored. A faulty rivet or a bad insertion could weaken the body and compromise vehicle quality and safety.

To ensure each body meets specifications, it is measured twice while it is being assembled. "We have an array of cameras that take a series of pictures of the body," Hoursoglou said. "The pictures are compared against a known master, and that will give us the measurement. We measure the underbody of the car, the key characteristics, of every single car.

"If there is a damaged part, we will pick it up before it goes any further. The system is designed so that the line will lock down. That car can't go any further forward until we understand whether it is a measurement issue or there really is a problem with the car," he added.

Refinements since 2008


Ford sold Jaguar Land Rover to Tata Motors in 2008. Since then Jaguar Land Rover has continued to refine the aluminum production system largely developed by Ford engineers in Dearborn.

For instance, engineers developed for the Range Rover and Range Rover Sport one-piece side panels, currently the industry's largest stampings. This helps speed up production.

It takes Land Rover just over 10 hours to build each aluminum Range Rover body -- and that's not fast enough to meet demand. Hoursoglou says the goal for the next generation of Range Rovers is to cut the time to eight to nine hours per body. Reducing the number of rivets and changing the coating process are two ways Jaguar Land Rover could increase production, he says.

"Rivets and glue are like having a set of pants with a zipper and buttons. You don't actually need them both -- but if you've got both, basically, your pants are never going to fall down."
Mark White
Jaguar Land Rover

Three shifts


Jaguar Land Rover leads the industry in production of aluminum-bodied vehicles. Last year the company built 133,000 Range Rover, Range Rover Sport and Jaguar XJ, XK and F-Type cars, all with aluminum monocoque or one-piece bodies. That came in a year of record global sales for the company of more than 425,000 vehicles.

The automaker is running three shifts per day Monday through Friday. Some countries have a six-month wait for delivery. More Range Rovers could be made more quickly by using steel, but White said there's no going back.

"What we want to do is have the appropriate technology that helps our customers get what they want. That's basically why we've adopted this approach. SUVs are traditionally heavy. Our goal is to take significant weight out and give them better fuel economy."

You can reach Richard Truett at rtruett@crain.com.


advertising
Have an opinion about this story? Click here to submit a Letter to the Editor, and we may publish it in print.

Or submit an online comment below. (Terms and Conditions)


Newsletters & Alerts
Latest Headlines