Quebec, Canada. Increasing demand for a lighter landing gear forced aero subcontractor Messier-Bugatti-Dowty to think in new ways. To achieve its goals it needed to rope in help from across two continents.

When Boeing and Airbus decided to create new, fuel-efficient wide-body commercial aircraft, the two manufacturers turned to Messier-Bugatti-Dowty to produce the main landing gear. That comes as no surprise. After all, Messier-Bugatti-Dowty, part of the Safran Group, is the world’s leading manufacturer of landing and braking systems. In fact, landing gear made by Messier-Bugatti-Dowty touch down more than 35,000 times a day.

Messier-Bugatti-Dowty’s Canadian facility in Montreal, which has produced the steel main landing gear fittings for a number of Airbus models for the past 20 years, was given the nod to manufacture the main landing gear fittings for the Boeing 787 and the Airbus A350-900.

Aerospace Fuel Efficiency Key

Both aircraft are scheduled to enter into service in the coming years and are designed to be among the most fuel-efficient airplanes in their classes. Much of that fuel efficiency comes from obtaining weight reductions throughout the aircraft, including the landing gear systems.

Eric Robiilard, methods technician at the Montreal facility.

“The weight of the landing gear has a direct effect on fuel use, so we try to lighten them as much as possible while respecting tolerances,” notes Gilles Pouliot, strategic buyer at the Montreal facility. Landing gear must support extreme loads and yet be light, compact, robust, reliable and durable. But during flight their weight is a drag on fuel efficiency.

For both new aircraft, the challenge to reduce weight in the landing gear was solved by producing a cavity in the axle section of the main landing gear fittings. Engineers designed a process in which part of the shaft of the steel main landing gear cylinders is drilled out. The process is known as “bottle boring” because the resulting shape resembles a bottle. Both aircraft are using the bottle boring process, which generates significant weight savings.

However, when Messier-Bugatti-Dowty started to use the bottle boring approach on landing gear for the 787, intiial results were discouraging. “We didn’t get the results we were looking for,” says André Martin, manufacturing and engineering director at the Montreal facility. “For example, it was taking too many hours to produce the bottle shape.”

“We work under extremely small tolerances, and had all kinds of problems with the previous manufacturing process,” adds Eric Robillard, methods technician and project head for the 787 landing gear at the Montreal facility.

Tooling Investments

That’s why the company made the decision to invest in new tooling and new machines that could produce the parts faster and more economically.

In 2007, Messier-Bugatti-Dowty began to evaluate new technology that would improve the bottle boring process. Enter Tacchi of Italy, which was chosen to make the machine, and Sandvik Coromant Canada, which was tapped to produce the tooling for the deep hole drilling that is required for the 787 and A350-900 landing gear fittings.

Mario Laroche, machinist, with the new bottle boring tool.

“The goal was to manufacture two different components using the bottle bore approach, so we had to work out the engineering, productivity and safety aspects of the components,” says Louis-Jacques Boucher, manager business development, aerospace, at Sandvik Coromant Canada, who coordinated the project. The project started in 2008 and involved Sandvik Coromant operations in five countries.

“It was the first time Sandvik Coromant has made a tool of this size and dimension — and the first time a tool of this kind has been developed specifically for us,” syas Pouliot. “It was a critical element for us.”

After the machine reached the Montreal facility in late 2009, Sandvik Coromant specialists were on site for several months to help develop procedures and work methods for the new tooling. “There was an enormous amount of work to do on both sides to solve technical problems and develop methods to optimize the cutting,” Martin says.

Simplifying the Machining Process

The machine and tooling are precision-regulated and are designed so they can complete the same process over and over again, like clockwork, he explains. “It’s like jewelry,” says Martin of the Sandvik Coromant-made tooling. “It’s an avant-garde tool that has to be able to produce the same part repeatedly with no variation and without adjustment.” The landing gear fittings for the 787 and A350-900 could be produced for 30 years or more, he says.

Integrating new technology on a new machine isn’t easy, but the Sandvik Coromant tooling “has made a huge difference in time and quality,” Robillard syas.

“The new tooling and machine have been so successful that our goal of a 50 percent reduction in the time required for the bottle boring process has been met and surpassed,” Martin says. “We’ve now achieved a 60 percent reduction and a 100 percent improvement in quality.”

When the process first started, “it was only theoretical that we’d reach the results we’ve reached today,” adds Pouliot, citing a strong partnership between Sandvik Coromant and Messier-Bugatti-Dowty.

That partnership also came into play when the company decided in 2009 to move manufacturing of the main landing gear for the Airbus A320 and A321 models from Montreal and Gloucester, England, to a new facility in Queretaro, Mexico. That move would allow the Montreal facility to concentrate on production of main landing gear for larger aircraft models such as the Airbus A350-900 and Boeing 787.

Expertise in Manufacturing

The recessing tool facing the workpiece at the start of the process.

New turnkey tooling, engineering, and manufacturing processes had to be implemented in Mexico, in an operation that was coordinated by the Montreal facility, with tooling and programming support from Sandvik Coromant Canada.

Sandvik Coromant Canada’s goal was to transfer its expertise in machining landing gear to Sandvik Coromant Mexico and to help Messier-Bugatti-Dowty implement new processes in Queretaro, says Marc Boisvert, technical representative at Sandvik Coromant Canada. “We worked together for four months to develop new looking and machining methods, with Sandvik Coromant providing the parameters and cutting depths for each tool and best practice methods for machining.”

The Mexican facility is now operating successfully. The partnership with Sandvik Coromant on the bottle boring process and the new plant in Mexico “is a great example of the type of partnerships that Messier-Bugatti-Dowty likes to forge with suppliers,” Pouliot says. “They’ve shown a great willingness to listen to and meet our needs. There’s a high level of confidence, and the relationship is a real win-win situation for both of us.”

TECHNICAL INSIGHT: A United Nations of Sorts

Messier-Bugatti-Dowty's Montreal facility produces landing gears for both Airbus and Boeing.

It truly became a United Nations of Sorts when Messier-Bugatti-Dowty chose Sandvik Coromant Canada to create the complex tools required to conduct the bottle boring process for the main landing gear fittings for the Boeing 787 and Airbus A350-900. Headed by Sandvik Coromant, the bottle boring project involved the expertise of five countries and included engineering, startup support and in-house training.

Sandvik Coromant France was tapped to engineer and manufacture the bottle recessing tool, based on its past experience creating this type of tool. Meanwhile, Sandvik Coromant Canada and Germany were called on to manufacture peripheral equipment, including the pressure head, vibration damper and drill tube. The rest was designed and manufactured at the Sandvik Coromant Mebane facility in North Carolina.

Adding to the project’s international character, the first international meeting took place in Italy at Tacchi, which built the bottle boring machine for Messier-Bugatti-Dowty, and included representatives from the Montreal facility. That was just the first of several multinational meetings that took place.

“We had support and follow-up from around the world,” says Gilles Poliot, strategic buyer. “Everyone got involved.”

The end result surpassed expectations in cutting time, quality and finish, says Louis-Jacques Boucher, manager business development, aerospace, at Sandvik Coromant Canada. “Combining all of our resources and expertise made this project a true success in every aspect,” says Boucher.

Originally published in Metalworking World 3.2011, a business magazine published by Sandvik Coromant.

Text: Danny Kucharsky
Photo: Guillaume Simoneau