Walk along Mazda Motor Corp.'s Ujina No. 2 assembly line in Hiroshima, Japan, and you'll notice something strange. The racks of parts bins filled with parts waiting to be installed on cars are nowhere to be found.
Where are the parts? Downstairs.
Behind that answer, though, lies a story of how Mazda made a virtue of necessity when it reopened the aged factory last year. Mazda's experience offers lessons in how ingenuity can make even an out-of-date factory competitive.
Ujina No. 2 opened in 1972. Because of its location, the plant used a two-story layout. It is squeezed between the Ujina No. 1 plant and Hiroshima Bay. There is no open space for expansion.
In September 2001, Mazda closed Ujina No. 2 after building almost
6 million vehicles there. At the time, the automaker was shifting part of its production out of Japan to reduce its vulnerability to currency swings.
Then a string of strong products, such as the Mazda3, boosted sales and left Mazda short of capacity. Mazda reopened the plant in May 2004. It builds the Demio, known in Europe as the Mazda2, and is preparing to build the Mazda3. Its current capacity is 236,000 cars a year.
Two-story plants such as Ujina No. 2 or DaimlerChrysler AG's former Toledo, Ohio, Jeep plant are inherently less efficient than one-story factories. Hauling car bodies from floor to floor adds no value. So when Mazda decided to reopen Ujina No. 2, it sought a more efficient way to use the building's space.
Mazda reuses its resources. The
RX-8 sports car is only possible because older equipment is used to build the car's distinctive rotary engine. The Ujina plant itself was built on reclaimed land.
President Hisakazu Imaki, a career manufacturing manager, takes obvious pride in the reopened plant. But, in typically Japanese style, declines to brag.
"After touring the plant, a manufacturing expert told me, 'Anyone can spend money on automation. But you showed what the plant of the future should be,'" Imaki says.
The reopened plant boasts a number of improvements, particularly in the paint shop. But those improvements could have been included in any factory. What sets Ujina No. 2 apart is how Mazda turned the two-story layout into an advantage.
In a traditional final-assembly plant, as a car moves from one workstation to the next, a worker checks a sheet of paper dangling from the vehicle's open hood. That sheet indicates which parts and options go on that car.
The worker then selects the needed parts from various parts bins beside the line and installs them. Delivery trucks patrol the aisles to replenish the parts bins.
Parts from larger bins at Mazda's Ujina No. 2 plant are placed inside a single kit for each car. Elevators carry parts between floors.
But at Ujina No. 2, about 30 workers on the first floor consolidate all of the parts needed at one workstation for each car, based on the specifications sheet. Bar code readers scan the sheet.
Workers put parts from the larger bins into a single box or kit for each vehicle.
A light blinks above every bin that contains a needed part. An electronic eye sees if a hand enters the right bin to collect a part.
If the worker takes the wrong part or misses a part, a lamp signals the mistake. The system won't give the instructions for the next car until the mistake is corrected.
Once each kit is ready, it moves upstairs via a system of small elevators.
A line worker then hooks the kit to the car on the line. The kit rides down the line alongside the car being built. When all the parts in a kit have been installed on the car, the empty box goes back downstairs to be refilled.
Not all parts are handled this way. Mazda began with tires and wheels, window assemblies and instrument panel components. It has added other parts and systems gradually.
Kits handle more than 90 percent of all parts installed during final assembly.
The overall goal is to reduce the mental stress of the line worker, says Hiroshi Kamiya, a Mazda executive officer and manager of the Hiroshima plant complex.
"The operator doesn't have to select the parts" and can concentrate on installing them correctly on the cars, he says.
The kit also eliminates workers' movements that were designed solely to find and collect parts, by placing those parts alongside each car in a kit box.
Overall staffing at Ujina No. 2 is 85 percent of what it was under its previous manufacturing system, adjusted for the fact that the plant is on one shift.
The new arrangement moves parts through the system faster. The time from when a part arrives at the unloading dock to when it leaves the factory in a car dropped by 20 percent compared with pre-closure operations. At full production, that time will have been cut by 35 percent, Mazda projects.
The first floor's parts inventory is about the same as it was under the old system. But the inventory on the second floor has been virtually eliminated. And with the faster flow of parts, the plant's overall parts inventory has been reduced by 35 percent from levels at the time of the 2001 closure.
The new assembly process depends on two critical changes. First, Mazda needed more elevators to carry parts to the second floor. Second, Mazda and its suppliers had to do a better job of ensuring the correct parts were available to the line worker in the order in which they were needed, a process known as sequencing. First-floor workers
couldn't prepare kits for sedans if the only parts they had in stock were for hatchbacks.
Some elevators were carryovers from the plant's former layout. They had been used to lift large, heavy containers of parts to delivery trucks on the second floor.
Parts also once were driven to the second floor by forklift trucks on a ramp connecting the two floors.
Mazda built one elevator, similar to the those already being used, at a cost of about ¥30 million, or about $268,000 at current exchange rates. Then it decided it could do better.
The old elevators were designed to lift huge containers carrying hundreds of a single part. The new elevators only had to be large and powerful enough to lift individual kits with a limited number of parts.
Mazda adapted a simple method used by carpenters to lift tiles onto roofs. Cost: $27,000, or one-tenth the previous cost.
Mazda managers informally call the new elevators "batchelators" because each carries one batch of parts. The elevators also are easier to remove and reinstall, in case Mazda wants to reconfigure the line in the future.
Ujina No. 2 has 15 of the old-style heavy-duty elevators and 25 of the newer batchelators.
To improve sequencing, suppliers increasingly must deliver their parts in a sequence linked to the production schedule. Before the plant closed in 2001, only eight parts were delivered from suppliers timed to sequence properly with the assembly line. That rose to 31 when the plant reopened. Now Mazda aims to raise that to 44. That experience in proper sequencing will prove invaluable as Mazda moves toward build-to-order manufacturing.
The build-to-order ideal is to build and deliver cars quickly, generally in two weeks or less, based on a customer's individual order. That would reduce expensive inventories that sit idle on dealership lots, thus helping curtail costly incentives.
Today, Mazda has reduced inventories at the assembly line. Tomorrow, Mazda may eliminate some of the excess cars on dealership lots, thanks to lessons learned at an outdated plant.