Until a few years ago the design and manufacture of a new aircraft involved a monumental exercise in sharing the physical design information with the various partners. Then came early computer-aided design systems, including Dassault's Catia, that enabled design data to be shared electronically, greatly simplifying the task.
Mock-ups of the structure and the complex systems within were still necessary, however, to ensure the thousands of components would fit and be accessible for maintenance.
While this was a huge advance on the days when the aircraft was described by means of hand-produced technical drawings, there was still plenty of margin for error, which meant a lot of time had to be spent resolving interferences, access issues and so on, each change requiring new drawings and calculations as to the overall effect on the rest of the design.
All that has changed with the Product Lifecycle Management (PLM) system used for the Falcon 7X. The entire aircraft is now described as a three-dimensional virtual entity, using Dassault's new Virtual Reality Centre at its St Cloud, Paris headquarters.
Engineers visiting the centre use stereoscopic spectacles to view all aspects of the 7X design in as much detail as necessary and can seemingly enter the structure to view pipes, electrical wiring or complete systems to check how they interact with the aircraft.
The power of the PLM system is that it enables everyone involved in designing and building the 7X to share exactly the same information. The entire design and manufacture process is now linked so that for the first time the digital model of the aircraft contains enough information to manufacture it.
As a result, Dassault has been able to vastly refine its relationship with its suppliers by linking them all with the Falcon 7X database.
For the preliminary design phase all of the suppliers, initially numbering 400 people from 27 companies and seven countries, gathered at St Cloud.
Once preliminary design was completed, they returned to their companies to work together on Dassault's unique, shared database, connected through a France Telecom-supplied permanent high-speed datalink.
Design issues were settled in "virtual meetings", the effect of any changes on the rest of the aircraft being instantly visible. "It's the first time it has ever been done," says Falcon 7X programme director, Vincent Oldrati. "There's no comparison with the past, when incomplete data might have had to be released early to save time, which needed updating later. Now, all the changes are done in real time."
The result is a production engineer's dream. "Everything fits perfectly first time," says Oldrati. "There is no more adjusting or trimming parts. All the holes align, wherever the component comes from. For the lower fuselage, for example, we began assembly on 1 February [2004] from detailed parts and completed it by the end of April – that's twice as fast as before."
Assembly of the fuselage was finished by 14 July at Dassault Merignac, near Bordeaux. "That was a really big step forward," he adds.
Giving suppliers access to the virtual aircraft shortens decision times and means that they can present Dassault with solutions that need little or no modification before production of the aircraft can start. This is particularly true, for example, at Dassault's completion centre at Little Rock, Arkansas, USA.
"They've been involved right from the beginning," says Oldrati. "All ‘wet' items such as toilet pipes, galleys and so on were put into the database at the start of the design process so that they could prepare the interface with the basic aircraft. We just gave them the attachment points and they do the rest. Up to now, everything has to be adjusted for each individual aircraft, which can be a nightmare when you're dealing with the exotic items demanded by some customers."
PLM is also used to optimise tool design and operation, increasing cutting efficiency. There are 4,500 sheet metal components on the 7X, all of which can be cut exactly to shape using the virtual database. The same is true of machining, where three-dimensional simulation is used to check the milling machine's cutting trajectory, again saving considerable time and reducing wastage.
Dassault has also designed specific software to develop the tools necessary to mount piping and install connectors.
Pierre Bro, in charge of digital manufacturing at Dassault Argenteuil, explains: "The system analyses the pipe and decides where the supports should be. It can define the tool in the morning and supply it in the evening, then use the Virtual Product Management bending programme to bend it to the right shape. This is a revolution compared with how we did it in the past."
Source: Flight International
