Lamborghini Redefines the Future of the Super Sports Car 2/3 - Official Press Release

LAMBORGHINI SpA Europe: Official Press Release

Lamborghini Redefines the Future of the Super Sports Car

     2. The Innovative Monocoque of the New V12 Model
  2.1. The New Lamborghini CFRP Production Facility

2. The Innovative Monocoque of the New V12 Model

Carbon composite materials are a key technology for the automotive engineering of tomorrow, especially for high-performance sports cars. These materials made from CFRP combine the lowest possible weight with excellent material characteristics – they are very light, extremely rigid and exceptionally precise.

Furthermore, CFRP materials can also be formed into highly complex components with integrated functions. This reduces the number of individual parts when compared to traditional metal construction – thus enabling further weight reduction. Lighter cars have lower fuel consumption and fewer CO2 emissions. Most significantly, however, it improves the power-to-weight ratio – the deciding factor in the overall feel and performance of a sports car. A super sports car built using CFRP accelerates faster, has superior handling and better braking.

Monocoque makes the most of material characteristics
The cell of the future Lamborghini flagship super sports car is made entirely from carbon fiber and has been designed as a monocoque structure. The load-bearing structure of the vehicle is engineered as a “single shell” that functions physically as one component, thus taking full advantage of the extreme rigidity of CFRP. Formula 1 race cars have been built using CFRP monocoques for many years – and have proven their crash worthiness time and again. The same applies to road-going sports cars featuring monocoque technology – the carbon fiber occupant cell functions like an extremely safe roll cage.

Construction offer many advantages
Of course, the term “single shell” applies only in the descriptive sense – the new Lamborghini monocoque is made from a series of individual parts with specific functions, such as stiffening elements made from Braiding technology, that is one of the best technology to manage energy adsorption in case of crash. After the curing process, however, this structure functions as a single component – including the base section known as the tub and the complete roof.

The full monocoque solution offers advantages which other processes, like a tub where a metal roof structure is attached in a conventional manner, cannot realize. That’s why Lamborghini made the no compromise choice of the full monocoque, which weighs only 147.5 kilograms (324.5 lbs).

Extremely rigid construction
Superior passive safety is only one benefit of the extreme rigidity of a full carbon fiber monocoque - very high torsional rigidity is another. The monocoque is connected at the front and rear with equally rigid aluminum sub-frames, on which the suspension, engine and transmission are mounted.

The entire body-in-white of the future V12 model weighs only 229.5 kilograms (505 lbs) and boasts phenomenal torsional stiffness of 35,000 Newton meters per degree. This guarantees a superb feeling of solidity, but, more importantly, extremely exact wheel control with excellent steering precision and sensitive feedback. For the dedicated driver, both are essential for truly enticing driving pleasure. The new Lamborghini flagship responds to the most minute steering input with the stunning precision of a perfectly balanced race car.

Depending on the form, function and requirements of the individual elements, the Lamborghini development team selected from three main CFRP manufacturing methods within its technology tool kit. They differ not only in their production processes, but also in the type of carbon fiber and its weave and, most importantly, in the chemical composition of the synthetic resin used.

Resin Transfer Moulding (RTM): In this process the carbon fiber mats are preformed and impregnated with an exact amount of resin. Afterwards, they are cured under heat while the part is in the mold. Lamborghini has achieved a major breakthrough by further developing this method. Using the patented “RTM-Lambo” process, the final mold is no longer a heavy, complex metal piece, but is made instead from lightweight carbon-fiber parts, thus making the manufacturing process faster, more flexible and more efficient. An additional benefit of the RTM-Lambo process is the low injection pressure that doesn’t require expensive equipment.

Prepreg – The carbon fiber mats used in this method, commonly known as prepreg, are pre-injected by the supplier with a thermosetting liquid resin and must be stored at a low temperature. The mats are then laminated in molds and cured under heat and pressure in an autoclave. Prepreg components are complex to make, but have an extremely high-quality surface finish (Class-A surface quality) and are therefore the preferred option for use in visible locations.

Braiding – These components are manufactured by using RTM technology. This carbon fiber weave technology is derived from the textile industry and used to make tubular components for special applications such as structural roof pillars and rocker panels. The woven components are made by diagonally interweaving the fiber in several layers.

The monocoque of the new V12 super sports car is constructed using these technologies applied in a series of special processes. One significant advancement Lamborghini realized is the ability to use already-assembled monocoque elements as the mold for the next step in the process. This makes for a considerable simplification of the manufacturing process compared with conventional methods.

Epoxy foam components are also used within the monocoque. They are placed in strategic points to increase the stiffness of the monocoque by working as spacers between the composite layers while also dampening noise and vibration. In addition, aluminum inserts are laminated into the front and rear surfaces to facilitate connection with the aluminum front and rear sub-frame elements.

Because of the complexity of the materials and process outlined above, Lamborghini decided to produce its new monocoque completely in-house, managing one strategic step in the production process.

Quality control is an absolutely crucial factor – every single monocoque is measured to exacting tolerances of only 0.1 millimetres, facilitating the extreme precision of the overall vehicle. Quality control starts with the purchase of the carbon fiber parts. Every delivery of carbon fiber is certified and the material is checked regularly for compliance with quality standards. Lamborghini worked together with its suppliers to develop a world-exclusive fiber and resin system for its RTM technology. Ultimately, these materials and processes constitute an important part of Lamborghini’s worldwide leading expertise in the field.

2.1. The New Lamborghini CFRP Production Facility

Lamborghini has achieved an impressive level of innovation not only in the design and development of carbon-fiber structures, but also in the associated production technology. For the future twelve-cylinder flagship and its monocoque bodyshell made from carbon-fiber reinforced plastic, a brand new production facility was built at company headquarters in Sant’Agata Bolognese. Every single production step from receipt of the fiber mat rolls to completion of the paint-ready bodyshell is carried out in-house.

The new production facility is organized in five lines :

1. The prepreg parts are made on the first line. They meet extremely high demands for stiffness and surface quality, but require a high level of manual labor and must be cured in an autoclave under heat and pressure.

2. On the second line, parts and sub-assemblies are made using resin transfer molding (RTM) technology. This process is highly automated. The autoclave is not required, with curing taking place in a heated chamber. This is also where the prepreg parts from the autoclave and the epoxy foam parts are integrated into the RTM monocoque structure.

3. The third line is where the epoxy foam stiffening components are produced. The same components are then assembled as inserts into the pre-preg and RTM process.

4. On the fourth line the monocoque structure and the roof are fully machined, assembled together and measured.

5. On the fifth line, the finished monocoque is precisely connected to the aluminum front and rear sub-frames and all exterior bodyshell parts to create the finished bodyshell.

The prepreg line starts with the automated cutting of the parts. The computer-controlled cutting machine ensures maximum precision, as well as minimum cutting strokes and waste. The machine is located in a climate-controlled room, because the prepreg materials must be maintained at a low temperature until the final stage of the process. The subsequent laminating work carried out on the prepreg parts is handled by highly experienced specialists. They create the complex forms and ensure the highest possible aesthetic quality of the finished product. After a vacuum bagging process, The final curing takes place in two autoclaves. They operate at a pressure of 6 bar and a temperature of 135 degrees Celsius.

The RTM line commences once the dry fiber patches have been cut, with the automated pre-forming of the parts. The fiber mats are formed in a press – similar to the sheet metal presses used in conventional bodyshell manufacture. This technology enables complex structures to be produced to an extremely high level of precision. The final positioning process carried out on the parts is handled by lasers, where the pre-formed parts are are joined together in their final form on the tooling .Once the tooling is closed, the resin injection starts followed by curing at around 100 degrees Celsius.

Using the patented RTM-Lambo technology, the moulds are made from carbon fiber instead of steel – in some cases, the component just completed serves as the “mould” for the next step in the process, to which the additional parts are simply added and co-cured. A tolerance of only 0.1 millimeters applies throughout.

On the assembly line, the monocoque is connected to the aluminum sub-frames and all additional parts ranging from the front spoiler to the rear diffuser. At this point, every vehicle is measured in its entirety; the automatic precision measuring system works partly with lasers and partly by touch. Surface quality is ultimately checked in a light tunnel by highly-trained specialists. Finally, the body-in-white is signed off for painting and for full vehicle assembly.