Daewoo Heavy Industries (DHI) has begun deliveries to Northrop Grumman of the first computer-designed fuselage frames for the Boeing 747-400, as part of wider expansion by the South Korean company of its civil aerostructures subcontracting business.

Under a new contract signed with Boeing and Northrop Grumman in September 1997, DHI has increased its 747 workshare from 48 to 217 stretched upper deck frames. DHI is no longer subcontracting out fabrication of the upper deck frames to local suppliers and has moved the work back into a new production facility at its Changwon plant.

Its former Fairchild Dornier 328 fuselage shop has been re-equipped with new automated riveters and an automated tool storage rack housing the 58 separate flexi-jigs needed to produce the different frames.

Changwon has been linked via satellite to Boeing's mainframe computer, running the IBM/ Dassault Systèmes CATIA design system which uses CATIA data for tool design, component machining and inspection.

The new accurate fuselage assembly-produced frames include hole-to-hole pre-drilling for stringer clips to be fitted later by Northrop Grumman during fuselage assembly. "Compared to previous conventional upper deck frames, the current tolerance level is between half and two-thirds depending on areas," says Y J Hwang, DHI Aerospace general manager.

The South Korean company is the first 747 subcontractor to begin supplying CATIA-designed frames. It will be followed by Nippi of Japan this month and South Korea's Samsung Aerospace by the end of the year. After an initial proof of concept phase, the first Northrop Grumman panels are now in final assembly with frames, stringers and skins attached. DHI's sole supplier contract covers some 300 shipsets, as well as the nearly 500 upper deck frame shipsets to have been delivered since 1986.

In the meantime, the company has also been contracted to supply Boeing 777 nacelle fittings and recently concluded supplier contracts with two Airbus Industrie partners. It will shortly begin supplying A320 section 15 upper shell panels to Daimler-Benz Aerospace and, in June, concluded a deal to produce A330/A340 machined wing ribs for British Aerospace.

Source: Flight International