Toyota: A Car Every 20 HoursBy Mel Duvall | Posted 2006-09-05 Email Print
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Behind Toyota's assembly line are sophisticated information systems supporting and enabling the business processes that help the automaker eliminate waste, limit inventory buildup and continually improve production.
A Car Every 20 Hours
In the world of lean manufacturing, the real magic takes place on the factory floor in Georgetown, a city of about 20,000 located 13 miles north of Lexington, Ky. Toyota's thrust into the land of the Big Three automakers sits off Cherry Blossom Way, just a few miles past a Wal-Mart, McDonald's and Applebee's.
One of the first things that strike you about the plant is how open, bright and airy it feels. There are no floor-to-ceiling shelves stocked with parts for the assembly line, but there is a constant buzz of vehicles and self-guided robotic carts shifting parts directly from loading docks or staging areas to the line. Little musical jingles are heard everywhere—they all seem to sound the same to visitors, but assembly line workers can tell just by the jingle if there's a problem at their workstation and what might be the cause.
One of the key ways Toyota transformed the world of automotive manufacturing, says the University of Michigan's Liker, is by introducing the concept of one-piece flow—a production technique competitors are still struggling to adopt.
In Henry Ford's world of mass production, processes are designed to produce components or parts in large quantities. In other words, bolts, gears, transmissions or seats are made in large quantities and pushed to the next stage of production, where they sit in inventory until needed. Mass production has significant benefits, as Ford proved. It can greatly lower the cost of producing individual parts or pieces, and workers become extremely proficient in a certain trade or skill.
But it also has its drawbacks. The first is the need to store and constantly shift inventory. The second is waste. If consumer demand suddenly shifts and there is no longer a demand for a certain vehicle or option, there may be thousands of units in the supply chain that are no longer needed. Also, if a part or component has a defect, that defect may not be discovered until some later point in production or after delivery, at which time thousands of units may have been produced.
The Georgetown facility was designed from the ground up to produce vehicles in a continuous flow. Once the body frame comes out of welding, it is loaded onto the overhead conveyor system to begin its journey through the plant. Each job on the assembly line is designed to be completed in exactly 55 seconds, the amount of time before the conveyor moves the vehicle to the next stage of the line. At one station, a worker sits on a floating chair that moves inside the car frame, allowing him to stuff in insulation, then moves him out again to wait for the next vehicle. At another station, the entire engine is lifted up into the car chassis and bolted into place by two workers who hardly break a sweat.
Everywhere in the facility, parts arrive from loading docks or staging areas, just-in-time to be installed in the exact car they have been configured for, from a red spoiler to power windows. Perhaps the most remarkable example of just-in-time, however, is the seat installation area. Here, seats arrive from a nearby Johnson Controls plant every four hours, in exactly the right sequence and format to match the car on the assembly line—be it beige leather bucket seats, or a fabric three-seater bench.
Coordinating this incredibly complex scheduling ballet is software, proprietarily developed by Toyota, which it refers to as its Assembly Line Control System (ALCS). The software went through a major redevelopment about five years ago, and was ported from a mainframe to a client/server system. Marshall says the reason for the refresh was to make the software more flexible so that it could run at a global-scale plant like Georgetown, or at a smaller-scale plant like the one it operates in Thailand. Georgetown now uses a combination of Hewlett-Packard and Windows 2000 servers to host the application. The software essentially controls the sequencing of parts with the assembly process, ensuring that the exact components, such as black leather seats or power windows, meet up with exactly the right vehicle on the line.
Another major piece of software in use on the factory floor is a monitoring system from Activplant, based in London, Ontario. The software, called Activplant Performance Management System, essentially monitors all of the various machines, robots and computerized devices on the factory floor, keeping track of things such as malfunctions, uptime and reliability. The software collects information via programmable logic controller (PLC) devices, essentially small computers used to program and control factory machines and robots.
The Activplant system can tell Toyota, for example, who the operator of the equipment was at the time it broke down, what the conditions were, speed of operation, temperature and the downstream effects on the assembly line. The advantage, according to Marshall, is that it provides Toyota with live data so the automaker can act faster to prevent assembly line disruptions, and drill down to investigate causes and effects. In terms of business process management, it can provide Toyota with key insights into factors such as which equipment tends to cause the greatest disruption to the assembly line, so it can prioritize new capital investments.
The most time-intensive part of the vehicle assembly process—almost half of the total—is spent in the paint shop. Until recently, this was one area where Toyota was stymied in its attempts to maximize business processes and achieve one-process flow. That's because it had been difficult to paint a white or red car after a black car. Every last drop of black paint had to be removed from the tubes of the paint-spraying robots with solvents. For that reason, Toyota had to paint vehicles in batches—the mass production way, and contrary to the tenets of TPS.
But where other manufacturers might have accepted painting in batches as a fact that could not be altered, Toyota did not. TPS required that it constantly look for ways to overcome Muda. Toyota formed a partnership with ABB Automation Technologies, a Zurich-based maker of manufacturing robots, to pioneer a painting system that uses swappable cartridges. In 1999, it began installing the technology in its plants worldwide.
Now, when a car enters the paint shop, the ALCS tells the painting robot the exact color required; the robot grabs a red cartridge for a red car, or a blue cartridge for a car to be painted blue. Cleaning with solvents is no longer necessary. Toyota estimates the process saves about $29 per vehicle, and takes 2.1 hours off the time needed to produce a vehicle. At Georgetown, it was able to mothball one of three painting booths because of the more efficient process.