Jaguar Cars is making increasing use of the latest rapid prototyping technologies at its Whitley Engineering Centre to speed the development of new vehicles by making plastic parts directly from CAD models, and eliminating the expense of producing mould tools
Jaguar Cars is making use of laser-sintering machines from EOS to create prototype trim and even engine parts from nylon powder (polyamide PA2200), fusing them layer by layer into their respective shapes. The resulting components, such as air intake manifold, door internals, fascia substrate, interior air vents and exterior light housings, are robust enough to be used on test vehicles running around the track, allowing more data to be collected early on in the development process.
The V8 air intake manifold prototype for a forthcoming Jaguar car, is particularly illustrative. In the past, hundreds of thousands of pounds would have been invested in hard tooling for its manufacture. Following every design change, it would have cost thousands of pounds to alter the tool, a process that took weeks at a time. If the changes were substantial, a completely new tool might be needed.
Using laser-sintering RP technology, two design iterations of the manifold were produced and 17 were subsequently built in nylon for less than a thousand pounds each and in a lead-time of one and a half days per manifold. It represented an enormous financial saving in the development of this vehicle component alone and has halved the time needed to perfect it from one year to six months.
Two EOSINT P380 laser sintering machines (P360s, software upgraded to P389 performance) currently operate 24/7 at the Whitley Product Development Centre, producing within their 340 x 340 x 620mm build envelope a myriad of PAG parts, for which the STL files are managed in a database with scheduling capability. Parts are positioned using Magics software from Materialise for optimum use of the build volume. Jaguar's experience has been that the throughput of laser sintered parts exceeds that of other RP processes, as the entire build volume can be filled with parts whereas with the other processes it operates, parts may be fitted within the area of the build platform only.
The nesting flexibility afforded by the EOSINT P380s makes it easy to incorporate dozens of parts in each sintering cycle. An interesting component that is regularly added around other parts is not a prototype at all, but a complex plastic assembly aid that assists operators working on the recently revealed XK coupé and convertible to position the window lift mechanisms during build. A stock of 3,000 of these parts was required by the manufacturing plant, as once fitted, the assembly aid remains on the vehicle throughout the build process. By August 2005, around half of the parts required had been produced on the P 380s as fill-in jobs, without the need to invest in expensive plastic injection mould tooling.
As to the future, Jaguar expects to see rapid prototyping quickly develop into rapid manufacturing processes, initially capable of satisfying niche requirements. In the more distant future it is possible that today's RP processes hold the key to the next generation of volume production technologies where the design constraints, tooling and inventory overheads of today's processes might be eliminated. It is certain that Jaguar will continue to produce plastic components for prototype and niche applications such as the window lift assembly aid, following the success of the XK window tool project.