While the market is focused on the performance improvements will bring with the third generation of the 777 family, the program's factory leaders have spent the past 18 months introducing robotic manufacturing systems for painting and riveting that are considered essential for a smooth transition to production of the new airplane models.
In 2005-06, Boeing was willing to entirely rejigger the 777 final assembly process to make its flow more efficient, despite the fact that the big twin-engine transport's second family—the, -200LR and Freighter—were in their early days of service and flowing through the factory along with stalwarts of the first generation, particularly the -200ER.
Continuing refinements of the new line have brought results across multiple variables: parts shortages are down 57%, overtime has been reduced 38% even as production rates have climbed from three aircraft a month to 8.3, and quality as measured in reduced defects has improved by 26%. But even as the new U-shaped line was registering these gains, “it is still a craftsmanship-based system” that requires hours of hand work by mechanics, says 777 Operations Director Jason Clark.
To reach its target of cutting production flow time by 25% over the next two years, Boeing is increasing automation levels. The focus is on processes that are stable and repetitive regardless of the model type, says 777 General Manager and Vice President Elizabeth Lund. Improved tooling and better software provide the flexibility to quickly adjust automated tools to each different model on its path through the factory. She calls the process and tooling improvements “unseen investments,” essential to a smooth introduction of the coming 777X variants.
The most widely based improvement is adoption of the Flex Track automated riveting system, which Electroimpact Inc. based on an original Boeing design and now markets widely throughout the industry. Boeing is considering the tool, which it first used on the 777 18 months ago, for use on the 767 andprograms. Flex Track's head both drills the holes and places the fasteners while moving along parallel guide tracks. The device can be positioned to work around the circumference of a fuselage section or along a wing. It is operator-controlled by a hand-switch connected to it via an electrical umbilical cord.
“When we opened the box we got a 93% improvement in quality,” Clark says. He cites reduced gouges and scrapes from hand-driven installation. Once crews became more accustomed to using the tool, quality improvement hit the 98% level, he says.
Since introducing an automated floor drilling system from MTorres last year, Boeing has found it is 3-4 times faster than existing technologies for attaching floor panels to a floor grid. The system has been used on 50 aircraft and has the advantage of being flexible enough to adjust to different cabin configurations.
The most recent addition is an ABB-developed automatic painting system being used for 777 wings. The 19-axis painter can complete a 777 wing in 24 min. versus a paint crew's average time of 4.5 hr. The system's paint heads have an 18-ft. reach rather than the 4-ft. span the average human can attain, Clark says. More important, it sprays so evenly—leaving no “heavy spots”—that Boeing is seeing an average 79-lb. weight reduction per wing. Other benefits include a 20% improvement in ergonomics, a 70% environmental payoff, a 25% reduction in defective paint spray and flow-time improvement of 40%.
So far, the sprayers are only being used to spread the PMS 1060 standard gray paint on wing surfaces, which produces less drag than the PMS 1072 used as body paint. But the sprayers are being considered for use on fuselages, given that this portion is often heavily masked for customer liveries.
Flow times through paint hangars can be an impediment to the production flow. Boeing's installation of hangars just off the final assembly line for painting vertical stabilizers is credited with allowing it to move from a 7-aircraft-per-month production rate to 8.3, or 100 a year. Previously, the stabilizers were painted in the main fuselage paint hangar that is separated from final assembly, a process that ate into flow rates.
The booths that house the automated sprayers are large enough to accommodate the 777X family's all-composite wing. Boeing has not revealed its specifications, but it is expected to be in the range of 233 ft., the longest of any of the company's aircraft.