Flow time for Boeing 737s through the company's Renton assembly site in Washington has been cut from 23 to 18 days with the application of a moving production line, and is expected to reduce further to 17 days by the end of January, says Boeing.
Unlike the original Boeing chain-driven 717 moving line at Long Beach, California, the aircraft on the Renton line are moved along continuously by automated guided tug vehicles. The tugs are hitched to large work platforms that move along the line with the aircraft as it is assembled. Three of the four positions on the first moving line, number four, are occupied. The fourth is expected to be aligned later this month.
Line number three, the second 737 assembly line, is due to follow line four's transition later this year. "When it does so the flow time will go to 50% of its original duration," says Boeing.
Moving-line simulations also continue on the single remaining 757 line, number one. The second 757 line was de-activated at the end of November 2001, although Boeing says the closure was planned well ahead of September and reflects improved efficiencies, rather than the recent drop in orders. Unlike the 737 line on which the aircraft are pulled by tugs, the 757s are pushed by special tugs attached to the nose gear. Only two of the four final assembly line positions are presently aligned, and Boeing says there is "no timescale yet" for the final implementation of the moving line on the larger twinjet.
Source: Flight International
