Ford converting plants to flexible manufacturing

  • 12-Nov-2008 09:01 EST

This Ford flexible body shop station has a balcony above the transfer line along which body assembly occurs. Robots are located both on the balcony and at the sides of the transfer line. A large access opening in the balcony above the transfer line permits robots to pivot down to apply spot welds.

Keeping the assembly lines going at a cost-effective pace, when public tastes may shift as fast as the price of oil, is a challenge that can be met only with highly flexible manufacturing. With a seemingly permanent shift by consumers to smaller, fuel-efficient models, Ford Motor Co. not only has to make its plants flexible but bring in the right products for them to build.

Getting the plants ready is the job of Joe Hinrichs, Ford's Global Manufacturing Chief. To start, he said, Ford is undertaking a changeover in three North American truck/SUV factories, including those in Louisville, KY, and Cuautitlan, Mexico, as well as the Michigan Truck Plant in Wayne, which is adjacent to a plant that produces the Focus. When the conversions are complete, the two U.S. plants initially will make cars and crossovers based on the global C-platform (Focus size). The Mexican plant will begin by building the smaller Fiesta. The Michigan truck plant is scheduled to begin C-platform production in 2010.

Flexible manufacturing is not the ability to produce differently badged vehicles primarily with trim differences, such as the Ford Expedition/Lincoln Navigator and Ford Escape/Mercury Mariner. That has long been done. The object is to be flexible enough to make truly different vehicles in different sizes. Although it even would be possible to produce unit-body and body-on-frame on the same flexible lines, that would push flexibility into less efficient levels, Hinrichs said. However, he continued, if all were unit-body, a size smaller and/or larger than the primary one could easily be accommodated, such as a C-size line also making smaller ("B, C") and larger ("C, D") models. Going beyond those limits, he continued, would require greater robotic operating range, and the greatest efficiency and quality is with smaller, simpler robotic movements. But even within those size ranges, a crossover, sedan, coupe, SUV, and luxury versions of them could be accommodated on the same line, he noted.

Key to flexible manufacturing is the design of each vehicle and its components. There must be common assembly locating points for all vehicles, and the assembly process must permit almost all of the same tooling to be used. With virtual manufacturing, the process can be commonized on the computer and all tooling clearances verified for the different models and components, including powertrain.

Even before the assembly line tools and equipment are installed in the factory, virtual manufacturing can show that all aspects of the system should interface and work harmoniously. This is more likely to lead to a vehicle launch with fewer problems and higher build quality.

In a flexible Ford body shop (a line where the metal sections form the body), about 80% of the welding robots can be programmed to switch between different types of vehicles. At present, 87% of Ford body shops worldwide are flexible, including the one at the Michigan Truck Plant, and Ford will have converted all remaining shops by 2012.

The body shop, indicative of the flexible approach, has stations with a balcony surrounding the body buildup transfer line. Robots are strategically placed both on the balcony and at the sides of the transfer line. The robots can reach down from the balcony as well as pivot in from the sides of the line to position components and apply the maximum number of welds at an individual station.

Ford paint shops also already are largely flexible, Hinrichs said. The robots can be programmed to apply paint to cover different body styles properly, with minimum paint waste. The primary upgrades some shops may need are deeper dipping tanks for larger vehicles.

Body and final assembly are where much engineering work remains to be done by Ford. The build sequence must be compatible with all the vehicles to be built, and the assembly lines must be configured properly for the sequence to work efficiently. As an example, Hinrichs said, an instrument panel must not only be installed in the same way on all vehicles but also be installed in similar assembly conditions, such as with doors off, which is now the Ford universal method.

"World" cars and trucks enhance overall manufacturing flexibility. Ford is confident it will overcome the difficulties it faced with its mid-1990s world-car attempt—the European Mondeo platform that spawned the U.S. models Ford Contour and Mercury Mystique. Because the U.S. market would not support the European price point for compact cars, the Contour and Mystique were re-engineered and de-contented compared with the European Mondeo in an effort to reduce cost and still were not successful in an era of cheap gasoline.

Most Ford assembly plants are designed to be most efficient with two five-day shifts, Hinrichs said, but if demand is high, it is invariably less expensive to add a third shift than open a new plant. Three four-day 10-hour shifts over seven days provide factory maintenance advantages over three eight-hour shifts in five days, he added, but with the former there is possibly the added cost of weekend operation, the amount dependent on labor agreements.

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