Manufacturing plans for the new mid-engined McLaren Automotive MP4-12C are moving ahead, with production slated to start in 2011 at the new €45 million McLaren Production Center (MPC) in Woking, near London.
McLaren has devoted what it terms “immense care” in planning the production process and its manufacturing facility for the car.
Road car production experience for McLaren started in the 1990s with the three-seat, road-going F1. But “production” was a relative term. The F1 was complex to construct (it took 3000 man-hours to build the original F1 carbon chassis), and only 107 units were completed over five years.
After that came the Mercedes-Benz SLR McLaren that demanded a higher (but certainly not high) volume. Operations Director Alan Foster, responsible for production and quality, had extensive experience with large Japanese and European manufacturers when he joined McLaren in 2005, and he successfully applied this knowledge to the small-scale, hand-built model. At peak volume, the SLR line produced 70 cars a month (average four a day).
“On the SLR line there was typically 225 minutes’ work at each station,” said Foster. With testing and final checks it took almost 1000 hours to make the car of which, by December 2009, more than 2100 units had been built.
Production of the SLR was in the heart of the McLaren Technology Center (MTC), under the same roof as McLaren Racing in the production hall and below the engineering and design offices. This close location of designers, engineers, and production has established the pattern for the MPS, which, like the SLR, brings a large-scale, lean production mentality into a small-scale, flexible, and bespoke operation.
“Quality is the most important thing to customers,” said Foster, “and quality management is the fundamental part of building a McLaren. For my team it is an absolute passion.” His team introduced a series of quality improvement processes over the life of the SLR that will be used as building blocks to meet even tougher quality targets for the 12C.
These include production-led problem identification, via which the production team is empowered to raise any issue slowing it down, with a daily review enabling engineers to respond with a quick and permanent fix. These reviews link to analysis of defects arriving at the final quality gate and to the production station where they occurred. The net effect for the SLR was said to be a reduction in defects to virtually zero in two years.
Foster stated that it is very difficult to deliver new processes into car production lines, especially ones that may highlight an individual’s or a team’s issues. “But we found that collective ownership and responsibility towards issues had the opposite effect," he said. "It resulted in more personal pride in the product, and production improvements that delivered, I believe, the best quality build in the car industry. What was learned will form the foundation for the 12C production process, where we will continue to adapt and innovate in production as volumes of McLaren cars increase.”
New models or derivatives may appear annually after the 12C.
For the 12C, production processes were built into the development plans from the earliest phase. So were production fixtures, which were used in the build of a series of XP (experimental prototype) cars in 2009. The XPs have been used for crash tests, dynamic testing, engine and transmission trials, electrical work, hot and cold weather trials, quality maturation of components, and durability testing. They also undergo geometric testing and monsoon tests.
XP Beta cars were then built in late summer 2009, incorporating many changes garnered from the XP testing program. They are close to production-ready cars.
A total of 26 VP (vehicle production) cars are now being built to continue various aspects of the test program and to validate results and facilitate certification in world markets. They also test the production process.
That process will see the hand-built philosophy developed for SLR applied to the 12C. The body fixtures for each station were designed by McLaren from the program’s conception and some have been used in the XP phase. For the VP series, the full complement of fixtures will be incorporated in the MTC production hall to replicate the exact process that will be used in the MPC proper in 2011.
The process consists of 32 assembly stations and seven main body building fixtures. Said Foster: “Each cycle time is targeted at 45 minutes, although some are already as low as 38 minutes, so we know that we have eliminated the risk in the process. The VP series we are building now allows us to prove the manpower loading, component layout, sequencing of parts, workload distribution, iron out team sizes and communication systems, and check for any bottlenecks in the process. The build process will be similar to that of SLR but at a much higher tempo."
Carbon fiber tub in 4 h
“The much faster tub production of around four hours and careful planning of the assembly process means I am aiming for a build time target of just over 100 hours, compared to the 800-900 hour build of an SLR,” Foster said.
The 12C has a one-piece carbon-fiber MonoCell chassis. Following McLaren’s design of the MonoCell, it has pioneered a new production process with global partner companies Carbo Tech (Austria) and Toray (Japan). It allows the tub to be produced through a new single molding process in a single piece, in four hours.
The MonoCell is made in a new resin transfer molding process. Dry carbon-fiber preforms are cut to shape and laid out in a multipiece complex-part metal mold with coring technology that adds a further property—the MonoCell is hollow. All parts of the tool close simultaneously. The tool then goes into a press that restrains the mold against pressure at a constant temperature. High-performance epoxy resin is injected at very high pressure, permeating the whole tub, and the resin cures to deliver the tub’s strength.
The finished tub emerges in one piece and various finishing processes are completed on a computer-controlled milling machine. At this stage, the interfaces between the tub and the front and rear aluminum crash structures are machined to ensure repetitive accuracy.
The production and quality teams were heavily involved in the design of the 12C from the beginning of its conceptual design phase, a major element of achieving dramatically reduced assembly time. Initially, McLaren is planning to build 10 cars a day.
Sustainable factory design
The 32,000-m² (350,000-ft²) MPC is located to the southeast of the existing MTC, and the two buildings will be connected by a subterranean walkway. The new building is designed to be sustainable: the MTC uses the site’s lake for cooling, so the roof of the MPC will further support this system, collecting rainwater to complement a low-energy design that uses displacement ventilation.
The linear arrangement of the two-story structure mirrors the flow of the production line: components are delivered, and cars are assembled, painted and tested, and then pass through a rolling road and monsoon wash before leaving the building. The basement level is used for storage, and above is a mezzanine floor with views over the production line. The MPC currently is under construction.
The paint shop design in the production center is completely new. It will be manually operated and all residual spray waste collected as electrostatically discharged limescale cake. It would be possible to robotize the painting process in the future if the volumes required it.
“The MPC has been organized along the lines of a large OEM facility,” said Foster. “It meets and exceeds all requirements for sustainability, energy conservation, energy re-use, and sensitive environmental landscaping. The investment involved is between £40 and £50 million, and with this facility up and running we have the capacity to build around 4000 cars a year. We have future-proofed McLaren Automotive’s ability to capitalize on market demand through at least 2020.”
The McLaren MP4-12C is a two-seater powered by a twin-turbocharged V8. The 3.8-L delivers 450 kW (603 hp) and drives through a seven-speed dual-clutch transmission. Dry weight of the car is about 1300 kg (2866 lb).
Nonstructural body panels use aluminum and sheet molding compounds. Performance figures are expected to include a 0 to 200 km/h (0 to 124 mph) time of about 10 s and a top speed of 320 km/h (199 mph).