When Boeing executives decided to re-invent a critical element of the 777 production process two years ago, they knew it was going to be hard. Memories of the costly, three-and-a-half-year delayed entry of the 787 were still fresh around Everett, Washington.

And they were right.

More than a year after launching, the highly-automated process for building up the forward and aft fuselage sections of the 777 is months behind schedule, as workers grapple with the complexity of replacing a 25-year-old system with a completely different method.

“I’ll be really blunt with you. It’s not easy. There’s nothing easy about bringing on a pathfinder technology. And if it was [easy] we’d probably would have done it 20-30 years ago,” says Jason Clark, Boeing’s vice-president of 777 and 777X operations. “But the reality is those things, when we isolate it down, it will start breaking the productivity loose in the future.”

In the meantime, Boeing insulated the 777 production system from any delays caused by the new production process. The new fuselage assembly process was installed in a newly built wing of the sprawling widebody final assembly building in Everett. The existing fuselage build-up area in the 40-35 bay of the factory using the old method was preserved. So deliveries of fully assembled 777-300ERs and 777 Freighters are continuing at the regular clip of 8.3 per month on average, although this will decline next year to seven per month.

Setting up dual production lines allowed workers time to adjust to the most significant change in Boeing’s commercial aircraft production system since the 787’s shift to a globally distributed and mostly automated method for composite fuselage assembly.

The move to a composite wing allows the 777X to leverage the hard-earned lessons from using the same material on the 787 wing.

But Boeing also decided that the 777X family would inherit a stretched and slightly updated version of 777 family’s metallic fuselage. That decision carried implications for the production system. While Boeing has revamped the final assembly process of the 777 into a pulsed line based on lean manufacturing principles, the fuselage sections are built up with the same basic methods that Boeing developed for the 707 almost 60 years ago.

A rotisserie-like circular tool is used to build up the fuselage sections upside down in the 40-35 bay, with workers manually drilling, counter-sinking and sealing thousands of holes. Then pairs of workers drive fasteners into each hole, with one pushing the fastener in from the outside and the other applying back-pressure with a bucking plate on the inside.

For the 777X, Boeing resolved to transform this outdated and manual system with a new level of automated sophistication. Boeing has used robots to drill and counter-sink holes in fuselage and wing structures for more than two decades. But now the company also wanted to automate the two-person fastening teams with similarly-aligned pairs of co-ordinated robots. At the same time, Boeing believed it was time to stop building up the fuselage structures upside down.

Thus, the Fuselage Assembly Upright Build (FAUB) system for the 777 was born. It would be applied first on the existing 777, in order not to jeopardise the development schedule of the 777X with the risk of needing to learn a new production system.

Starting in mid-2013, a few months before the 777X officially launched, Boeing rented an empty warehouse in Anacortes, Washington, to start testing the new robotic drilling and fastening machines supplied by KUKA Industries. Boeing publicly unveiled the FAUB concept two years ago at the Farnborough air show. The original plan called for activating the FAUB concept in early 2015 in the newly built 40-27 bay. The old upside-down build-up method would continue feeding the final assembly line, but was supposed to be phased out as soon as this August.

But progress has been slow. Clark estimates that the transition to a FAUB-only process for the fuselage build-up may not occur until the end of the year. It could even be postponed until the middle of the next year, he adds. More importantly, by preserving the old system, Boeing has given workers time to adjust to the new system and fix any flaws.

KUKA’s robotic drilling and fastening machines are not the immediate problem, Clark says. If provided a set of perfectly assembled fuselage structures, the robots can perform their function as designed. The problem is getting the fuselage sections mated together perfectly.

In addition to introducing the automation for fastening, Boeing also removed that rotisserie-like tooling jig for building up the fuselage sections. Instead of massive tooling equipment, the fuselage panels are mated on a cradle in stations with no fixed tooling jigs. That means the large pieces must be tacked together without internal support structure holding them in place. To simplify the idea, Clark compares it to putting together large aircraft structures as if they were made of Lego.

“You really focus on parts needing to fit together. For lack of a better term, you want them to snap together. You’ve got to have some pretty big fixtures to locate them so you get them in the right spot and then you can do that tack,” Clark says.

Since opening more than a year ago, the FAUB process has built up 15 aft or forward fuselage sections of the 777, which is only the beginning. The next step is to open a secondary assembly line for low-rate initial production of 777s with completely FAUB-assembled sections. The second assembly line will be installed in the 40-24 bay, where Boeing is now closing the “surge” line for the 787. Boeing plans to build the at least 23 aircraft with the FAUB process on the LRIP line, then begin transferring the process into the 777 main production line in the 40-25 bay.

But the plan also includes contingencies to build more LRIP aircraft in the 40-24 bay if progress remains slow. The 787 proved how painful it can be to invent a new production process on a clean-sheet aircraft. With the FAUB, Boeing is also finding how hard it is to transform the assembly system of an aircraft designed nearly 30 years ago.

“This airplane was designed in an era when that’s not what you did. You brought them into large tooled jigs and you brought them into the shape of the tools,” Clark says.

“It’s hard. It’s hard on the guys,” he adds. “There’s a lot of training they’ve got to go through. There’s a lot of technology development that’s still going on. What really brings me to the realisation that we’ve got it right is that on every airplane it gets better, the quality improves. The whole quality of the system is untouchable. It’s not Six Sigma. It’s well beyond Six Sigma.”

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Source: Cirium Dashboard