Lean Manufacturing doesn’t happen in a vacuum. It usually demands a measure of leanness in the supply chain—in addition to the leanness in a factory’s own processes.
This was the case for The Boeing
The reason is that Boeing was going to be moving through uncharted territory in a hurry. No one had attempted before to apply a moving-line concept to what Boeing calls the systems integration phase of production. So the aircraft builder needed suppliers that not only could begin delivering the necessary automation within 10 months, but suppliers that also had the engineering capacity to help its engineers to develop the details as the project progressed.
Long committed to Lean Manufacturing, Boeing wanted to build upon the lessons that it had learned earlier from its experiences with moving lines on the 737 and 717 programs. Demand had been rising for the new 777s, so Boeing wanted the moving lines to generate more capacity and to make it easier and cheaper to build quality into its products. The goal was to reduce assembly time by 25 percent.
Because of the unknowns, the most difficult part of the upgrade would be systems integration. In this phase, the old process had used overhead cranes to put the aft and forward sections of the fuselage onto stationary fixtures so technicians could install the electrical, hydraulic and other systems. Then the cranes would move the sections elsewhere to be joined to the middle section containing the wings.
This method had some limitations. Among the most important were the load capacity of the cranes and the distortion to the fuselage sections caused by the movement. To avoid these problems, Boeing’s manufacturing engineers envisioned moving the sections through the process on a fleet of tugs, called “crawlers” because of their lowness to the ground. These crawlers would hold the cradle-like fixtures that support the fuselage and would pull a work platform as they roll-along the U-shaped assembly line at 1.8 inches per minute. Afterward, the crawlers would speed up to 9 feet per minute when taking the sections to the final assembly area to be mated with the middle section.
The concept would give Boeing two more major advantages. First, it would let its mechanics install the seats, storage bins, and other heavy interior fixtures earlier in the process. These fixtures had added too much weight for the cranes to handle, so their installation had to wait until after the last move. Second, the crawler concept would allow incorporating a number of features from
For example, a moving line would allow workers to stop the flow, a tactic used in Lean Manufacturing to draw attention to problems. “Stopping production provides a visual cue to everybody that something is not right,” says Jay Palmer, Boeing national account manager for Siemens Energy & Automation Inc., in
Not just any suppliers would be able to deliver the crawlers and supporting automation in the allotted time. The crawlers are big vehicles. In the end, they would need a 55-ton capacity in order to hold and move a “stuffed” section of the fuselage. Each would need to be 80 feet long and 24 feet wide and weigh 20,000 pounds.
“A system this large involves 15,000 to 20,000 engineering hours for the mechanical design alone, not including the controls and electrical design,” says Benny Teal, president of NovaTech Innovative Technologies International Inc., the engineering firm in
As the lead contractors, NovaTech and Siemens needed a Lean mechanism for collaboration and delivery. They had to complete most of the engineering within five months to leave the remaining five months in reserve to make, install, and commission the system. “We had to begin manufacturing the major assemblies as they were designed, but before the entire system was completed,” explains Teal. “This, of course, generated tremendous challenges, both from a mechanical engineering point of view, as well as the control and power systems points of view.”
The engineering team met the challenge by establishing certain general requirements, such as capacity and maneuverability, and by breaking the system into smaller subsystems, such as the chassis, wheels and brakes. Then it broke them down even further. “Once you do that, you can identify six or eight areas where design can proceed more or less independently of the other areas,” says Teal. “You have interface requirements, but you don’t need those details to be well defined in order to design the wheel, for example.”
Although NovaTech is primarily an engineering firm, its business model allows it to tackle tight projects like the one at Boeing. The firm relies on a network of contract manufacturers to build its designs. This network gives NovaTech the flexibility to find the expertise and manufacturing capacity that it might need for a particular project. For example, it outsourced the machining and building of the wheels to a precision shop in
“In all, we brought together manufacturing capacity from half a dozen shops and coordinated engineering from our team, Siemens, and another electrical components vendor in
Now that the crawlers are rolling in the systems integration phase of the production line, Siemens and NovaTech are busy on the next phase, the final joining of the fuselage sections. Boeing expects to be assembling all phases of the 777 on a moving production line by sometime next year.
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