A new, dedicated aluminium pressing facility and a redeveloped body assembly facility were constructed at Jaguar’s Castle Bromwich plant to produce the new XJ. After assembly, the bodies are shipped by road to the Browns Lane plant for final build.
Many of the new manufacturing techniques used in XJ construction were honed by the aerospace industry. Instead of the conventional spot welding used on a steel body structure, the new Jaguar XJ uses structural adhesives and rivets to assemble the unibody structure of aluminium pressings, extrusions and castings which form the foundation of the vehicle.
Each Jaguar XJ contains 3,180 rivets and more than 120 metres of adhesives. The combination of rivets and adhesives, which cure in the heat of the subsequent paint process, results in a body structure that is extremely strong and stiff but light in weight.
The new Jaguar XJ bodyshop facility makes extensive use of automation – not unusual in modern vehicle construction, but in this case very much state-of-the-art. Eighty-eight robots apply structural adhesives and install the self-piercing rivets in the vehicle structure. Extensive simulation work using powerful computer modelling tools, combined with prototype prove-out, has ensured uncompromising Jaguar quality in each step of the assembly process.
The body assembly operation is surprisingly clean and quiet. Gone are the sights, sounds, sparks and residue of a spot-welding process. Decibel levels have been significantly reduced throughout the assembly hall.
The lean manufacturing ethic of the new Jaguar XJ assembly process is configured for highly efficient movement of parts and components ensuring that each workstation is supplied efficiently with stock. The need for parts stores adjacent to each workstation has been cut dramatically, reducing the need for costly in-plant inventory.
Two in-house parts stores hold enough stock for approximately eight hours of assembly operation. Just-In-Time delivery from suppliers keeps these stores at their optimum fill rate.
Working Together In Virtual Reality
The new XJ assembly facility was designed simultaneously with the engineering of the new vehicle itself – in virtual reality. This gave manufacturing engineers the opportunity to configure an assembly plant before anything was actually built, so that the XJ’s entire body shop existed on computer prior to its installation. Every step of the production process, down to each movement of an individual robot, was modelled in this fashion.
The production of the new Jaguar XJ required a new, dedicated aluminium pressing facility. Designed, engineered and constructed by Jaguar Cars, the new 9600 sq m. pressing plant is operated and managed by a technical partner consortium, Polynorm Stadco, under a long-term operating contract.
Another key partner in the new XJ programme is Alcan, the supplier of all the aluminium used in the car. Supplying the pressing facility via local warehouses capable of storing up to 20 days’ supply of raw material, Alcan was instrumental in the development of the construction techniques used in the new XJ, and served as the primary technical resource in early feasibility studies.
The End Result
When the all-new XJ goes on sale in spring 2003, Jaguar customers will be buying not only the most advanced Jaguar ever, but also one of the most important ever. As an all-new, world-class luxury saloon, the XJ pioneers a lightweight vehicle architecture that represents a major step forward in aluminium-intensive automotive body structures.
There can be no argument that in designing, engineering and constructing the new XJ, Jaguar has moved both itself and the wider automotive industry forward in the drive to reduce weight and enjoy the resulting benefits in terms of performance, fuel economy, emissions, crash safety, vehicle dynamics and recyclability.
The new technologies and pioneering techniques not only make the XJ the car it is, they also reinforce Jaguar’s standing as a world leader in advanced vehicle design and relevant, user-friendly driver aids.Published 3 December 2002