MIZUSHIMA, Japan - A thin robot arm poises above a stack of brown paper at Mitsubishi Motors Corp.'s large car plant here in western Japan.
Suddenly, air suction lifts a single sheet off the pile. The robot swings the sheet of paper in the car's window, and drops it onto the floor in front of the driver's seat. With its temporary floor mat installed, the car moves on to the next station on the assembly line.
Elapsed time: 1 second. Less time than it took to read the above.
'If a worker had to do it, it would take three seconds,' explained Masaru Suzuki, deputy general manager of the Mizushima Motor Works' assembling production department.
The robotic paper drop, suggested by one of the plant's workers as part of its kaizen continuous-improvement drills, illustrates Mizushima's willingness to automate almost every step of the car-building process. That high level of automation, the work-restructuring that drives it and a remarkable level of assembly flexibility go a long way toward explaining why Mizushima is the world's most productive car factory.
According to the London-based Economist Intelligence Unit, Mizushima built an eye-popping 147 cars per worker in 1997, the most recent year for which figures are available. That was 20 percent ahead of its closest competitor, Honda Motor Co.'s Suzuka, Japan, plant, which built 123 cars per worker that year.
By way of contrast, the top plant in North America, the New United Motor Manufac-turing Inc. joint venture between Toyota Motor Corp. and General Motors in Fremont, Calif., produced 87 cars and light trucks per worker in 1997.
Mizushima managers are too modest to predict that their plant will remain the world's most productive, although that seems to be a given.
To meet strong demand for Mitsubishi's new line of mini vehicles, Mizushima's output last year jumped a stunning 41 percent over 1997 to 816,000 cars and trucks. And the new models were designed to be 10 percent more efficient to build than the ones they replaced.
Based on the assumption that the workforce over the full year averaged about the same as in 1997, Mizushima built an indicated 206 cars per worker last year.
Volume vs. value
The plant accounted for about half of Mitsubishi's noncommercial truck volume and roughly 23 percent of its vehicle-sales revenues.
The difference between volume and value lies in Mizushima's role as Mitsubishi's production base for its minicars, tiny cars and trucks powered by 660cc engines.
These include the five-door Minica, Toppo BJ tall wagon, Pajero Mini sport-utility and Bravo delivery van. The Minica, Mitsubishi's hottest model in Japan last year with sales of 126,244, is 339.6 centimeters long, 147.6 centimeters wide and 150.9 centimeters tall, and it rides on a 234-centimeter wheelbase.
Mizushima builds more than minis, though.
Its products include the Mirage and Lancer sedans, the FTO coupe, the Libero wagon and the new Mirage Dingo tall wagon. The top of Mizushima's line is the tall, brawny Delica Sports Gear, a four-wheel-drive minivan with sport-utility pretensions. It is 468.4 centimeters long, 169.4 centimeters wide and 206 centimeters tall, and it rides on a 280-centimeter wheelbase.
In addition to the assembly plant, the Mizushima complex includes a press and stamping plant, a foundry and an engine factory making Mitsubishi's 660cc mini engines. For purposes of comparison, the Economist Intelligence Unit study factors out engine-plant workers and others it views as not being involved directly in vehicle assembly.
Squeezing out minis?
At first glance, the prevalence of minis on Mizushima's lines seems the likely reason for its high productivity. After all, shouldn't Mitsubishi be able to squeeze more of the tiny models onto the line, thus raising output?
Not so, insisted Hokuto Sugita, vice general manager of the Mizushima complex. Line speed depends on the number of parts, not the size of the vehicle, he stressed.
'The number of parts is almost the same for minis as for regular vehicles,' Sugita said.
Indeed, during a recent visit here, the Mirage/Lancer final assembly line was building at a rate of 46 cars an hour, a bit off its maximum speed of 55 cars an hour, but well ahead of the 30 cars an hour being built on the Minica/Libero minicar line.
So Mizushima's productivity secret does not lie in its model mix. Neither is it due to any of the other nostrums cited by some industry analysts when explaining Japan's manufacturing success in the 1980s: close ties within the Mitsubishi Group, factories brimming with the latest and greatest equipment, and a young, hustling work force.
Everything is not new
Sandwiched between a Mitsubishi oil refinery and a Kawasaki Steel factory next to the Seto Inland Sea, Mizushima would seem to be an archetypical Japanese factory, woven into a seamless web with suppliers on one side and a port for exports on the other.
To some extent, the image is accurate. Mizushima's tire supplier, for example, is only 1 kilometer away and delivers tires preassembled with wheels in sequence to the final assembly line. All told, 31 suppliers are located within a few hours' drive of the plant.
But Mitsubishi's keiretsu of suppliers is hardly as tight-knit as some would suggest. Mizushima uses parts from Toyota Motor Corp. affiliates Aisin Seiki and Denso Corp., as well as from Nissan Motor Co.-linked Calsonic.
Nor is the plant's equipment all new or state-of-the-art.
The body shop replaced almost all its decade-plus welding robots recently because maintenance costs were so high that it was cheaper to buy new. Each of the two main, 100 percent automated welding lines is equipped with jigs to handle up to four different models and/or body styles.
Old must keep up
Likewise, the press plant boasts a new 4,000-ton transfer press bought in April 1998. Fed by zippy materials-handling robots, the press can and does operate at a remarkable one stroke every four seconds, stamping out two parts side by side with each stroke.
Workers can change dies in 5.5 minutes.
On the other hand, one of its other presses is 35 years old, and it is expected to keep up with the newer model. Aside from the two main welding lines, a smaller line building the Pajero Mini is 'zero percent automated,' laughed Suzuki.
Parts of the plant's conveyor systems are more than 40 years old. The paint shop remains something of a bottleneck and has been targeted as the first in line for a major overhaul that later will extend to other Mitsubishi plants' paint shops.
The key is maintenance.
Signs exhorting TPM - Total Preventive Maintenance - pepper the walls. The assembly line's tools are all pneumatic, rather than electric, so that the plant's own staff can maintain them.
Nor is the work force young
and gung-ho. Mizushima's average worker is just over 40 years old. Among the inspectors at the end of the automated welding lines, the only workers in that part of the plant, the average age is 50.
No need to run
But here are some of the innovations that, in the aggregate, add up to world-beating productivity:
On the final assembly line, workers don't have to run from job to job, as is seen in some assembly plants. An obsessive attention to material-handling processes means that workers rarely need to go far to get a part or a tool, or to install it
If a worker needs to attach five bolts, he pushes up on a dispenser with the palm of his hand, much as one might press for soap from a washroom dispenser, and gets exactly five bolts
Pallets bearing inbound parts have been made smaller than standard in some cases so that workers don't have to reach too far to pluck the part they need
Steering wheels arrive in containers laid out to match the model sequence on the line
A computerized system chooses the proper owner's manual by language that should go into each glove box, and the right manual pops up for the installer to grab without looking.
'You may think that the advantage of dispensing five bolts at once is very small, but if you do it throughout the line, the merit is very large,' Suzuki said.
This attention to set-up time, the time required to prepare to do a job on the line, extends even to robots.
For example, one of the slowest tasks for a robot is picking up a part. So when a robot arm reaches for a rear-axle strut, it takes an extra half second to grab a second strut as well. Then, while it positions the strut, another robot attaches it.
Six ideas a month
It's all part of the plant's extremely high level of automation.
Robots install instrument panels, windshields, deck lids, door seats, even the four plugs used to fill in the drip holes left during the painting process.
At one point, three-inch cubic blocks of blue noise-insulating foam line up for cars coming down the line. When a car is in place, a puff of air from a nearby tube blows the cube into the car's body, where it awaits installation by a worker.
That tiny bit of automation, like much of the rest of the improvements on the line, was suggested by a line worker in the company's kaizen program. The two are linked intimately.
'If you only use automation, and you don't do the improvements, it's not worth it,' Sugita said.
Each worker is expected to submit six proposals for improvements every month. Less than 1 percent of them are implemented immediately, Sugita admitted, and only 2.5 percent eventually get put into practice after modification. The rest go nowhere.
Still, the pressure to come up with new ideas pays off often enough to keep Mizushima on track towards its goal of reducing assembly time by 3.5 percent every six months.
With such a target, there's little risk of Mizushima dropping to the floormat position among the world's assembly plants.