Toyota Adopts New Flexible Assembly System

GEORGETOWN, KY — Look out world, Toyota Motor Corp. just found a way to get more efficient. A lot more efficient.

Acknowledged as a global authority on all things “lean,” Toyota recently unveiled for journalists here its Global Body Line, a radical, company-wide overhaul of its already much-envied flexible manufacturing process.

GBL totally revamps Toyota's previous Flexible Body Line assembly philosophy that's been in place since 1985. With GBL, Toyota says body assembly will be markedly more efficient, flexible and lighter-on-its-feet than with the 17-year-old FBL.

Toyota Motor Mfg. Kentucky is Toyota's first North American assembly plant to implement GBL. The new system was so painless to set up that TMMK ramped up for last fall's all-new '02 Camry at the same time it was installing the GBL line. TMMK's Plant No.1 now is a 100% GBL-compliant line that produces the Camry and Avalon. Plant No.2 here, which is still under way with its GBL refit, also will produce Camry and Solara at 50% utilization, leaving room for as-yet unnamed future products.

Here's what Toyota says GBL delivers over the already efficient FBL system:

To add salt to the wounds of auto makers that still see Toyota's old FBL as the bogey, Don Jackson, vice president-manufacturing for TMMK, calls the outgoing process “antique” in comparison with GBL.

GBL isn't exactly new. Toyota's been honing the process since its first implementation in 1996, in, of all places, a plant in Vietnam that assembles Camrys.

But that's the point, say Toyota executives. The GBL process was developed so Toyota could implement a common vehicle-assembly “platform” at any and all of its worldwide assembly locations — regardless of volume or method of assembly.

Toyota tried GBL first in Vietnam because it is a low-volume operation that relies heavily on manual labor. If GBL worked there, then it could be exponentially more efficient when applied to high-volume, highly automated assembly plants.

“The goal was to seamlessly manufacture our products in any country, at any volume,” says Jackson.

Toyota remains relatively guarded about all the details of GBL. “A lot of this is still pretty proprietary,” claims one executive. But the heart of the new system comes down to how vehicle bodies move through the body shop.

In the old FBL system, each vehicle required three pallets — each tightly gripping either a major bodyside assembly or the roof assembly and assuring its adherence to dimensional hard points — as the body panels traveled through the various stages of welding to the floorpan and to one another.

FBL's problem, as Toyota engineers saw it, was that each vehicle's three pallets limited the number of vehicles that could be in the build sequence at any given time. Georgetown, for example, was limited to a “rotation” of 50 pallets.

Equally vexing, the design of the pallets — which held the bodysides and roof panels from the outside — limited the access of welding robots and required a lot of floor space.

When ramping up for production, says Jackson, planners had to “guess” about how many pallets to build and work that guess into the plant's vehicle mix (FBL-equipped plants could handle as many as five different models). Bad guesses about pallet allocation were horrendously costly. Quick reaction to a change of production mix was discouraged by the 3-pallet system.

The GBL design solves those problems by replacing FBL's three pallets with a single pallet, one that now holds all three major body panels from the inside. This “master pallet,” layout in one swoop eliminated the need for predicting initial pallet demand, says Jackson.

Because each model or variant requires only the lone pallet, switching new models in or out of the production mix is a breeze. Thus the 70% reduction in time required to facilitate a model change.

And because it holds the panels from the inside rather than the outside, body shop robots — and there are plenty of them in the new GBL layout — now enjoy unprecedented access to the interior regions of the body-in-white.

Toyota engineers say GBL doubles the amount of floor space that can be occupied by robots, and, on a GBL tour here, every inch appears to be used. The number of robots has increased from about 250 to some 350, says Norio Ohno, TMMK's senior vice president-manufacturing.

New, highly advanced robots are central to leveraging the advantages of the GBL layout. A Toyota source says that GBL and Honda Motor Co. Ltd.'s similar new flexible manufacturing process (see story, p.29) both were designed to make the most of new-generation body shop robots that are smaller, more precise and more energy efficient.

Toyota says GBL's use of fewer multi-jig robots in favor of the new-generation, single task units is largely responsible for the line's smaller footprint.

The precision and “touch” of the new non-hydraulic robots is startling. In one sub-assembly area, viewers see two pieces of floorpan about to be welded. In most shops, this process would require several clamps to maintain dimensional accuracy as the welding tips “hit” the panels. Here, the robots' touch is delicate to the point no clamps are necessary. The panels don't budge when the welding tip makes its hit.

Toyota engineers say the GBL system is enhanced by initial vehicle designs that ensure commonality for various hardpoints. This makes it easier to accommodate a variety of models: GBL-ready plants now can build as many as eight, rather than five with the FBL system.

Even with the ability to produce eight different models, there is a limit to GBL's flexibility. Once pressed, engineers admit that not everything Toyota makes, from Vitz to Land Cruiser, can be produced on a single GBL line. There are two sizes, one for small and medium vehicles, one to accommodate anything larger.

The cabins for body-on-frame vehicles can be built using “partial” GBL tooling. Toyota employs a partial GBL system with a master pallet to produce Sequoia SUVs in its Princeton, IN, assembly plant.

Georgetown is the first North American plant to enjoy a GBL upgrade, says Jackson, but it is not the first high-volume plant to prove out the new process. Once low-volume capability was proven in Vietnam, Toyota in 1997 tested higher-volume production with the Prius in Japan, then moved to genuine high-volume application in 1998 with its Japan-made Vitz.

At Georgetown, the floor space freed by GBL allows a second GBL line — helping the plant achieve a recently announced capacity increase to 500,000 units.

North America, because of its high-volume plants, actually is one of the last regions for GBL fitment. More than 20 of Toyota's 24 worldwide body lines already have been converted, and the rest either are in the process of conversion or will be refitted for GBL in conjunction with upcoming model changes, says Toyota.

Next for North America is Toyota Motor Mfg. Canada Inc., in Cambridge, Ont., which gets GBL next fall, just in time to crank out the RX300, the first Lexus-badged vehicle built in North America.