CARBON FIBRE CONSTRUCTION
- The LFA employs a unique Carbon Fiber Reinforced Plastic (CFRP) body to achieve exceptional integrity and light-weight construction.
- A trio of sophisticated CFRP moldings comprise 65% of the cabin by weight, yielding a low 1485kg curb weight.
- Pursuit of new CFRP technology internally results in an advanced new joining process for CFRP and metal alloys.
- Internal development means this world-class CFRP technology is primed for future mass production in other Lexus models.
Keeping the car’s overall weight to a minimum was a fundamental requirement. So early in the development process, the team switched from aluminum construction to an advanced Carbon Fiber Reinforced Plastic (CFRP) body, yielding a weight savings of 100kg (220lbs).
In total, CFRP represents 65% of the cabin structure with aluminum alloy braces supporting the engine and suspension, representing the remainder. Within the LFA structural design, three different CFRP molding processes were used:
Prepreg
Prepreg is a hand-laid process, employing carbon fiber sheets impregnated with thermosetting resin. It creates an extremely stiff and stable structure. It is primarily used to form the main cabin frame.
Resin Transfer Molding (RTM)
RTM uses pre-formed carbon fiber components, which are later impregnated with thermosetting resin. It used on the transmission tunnel, floor panel, roof, and hood.
Carbon Fiber Reinforced Sheet Molding Compound (C-SMC)
C-SMC uses short carbon fibers pressed into a die. It is used on the C-pillar and the rear floor.
A unique CFRP cabin with aluminum alloy extensions to cradle the engine and suspension
Utilizing CFRP is a rare approach to performance vehicle construction, but what further distinguishes the LFA approach, was the decision to develop the sophisticated CFRP structure entirely in-house. An example of the benefit of this approach was the development of an automated weaving process with laser thread sensors that ensures fabric integrity along with dramatic production-time savings.
A highly sophisticated three-dimensional carbon fiber loom was developed specifically for the LFA program
The LFA team also developed an advanced joining technology to bond carbon fiber and metal components. Conventional joining processes use a threaded aluminum insert that is wrapped in the CFRP. However, the LFA uses an innovative system that required no insert or direct CFRP contact by employing a flanged aluminum collar to link the two materials, overcoming inherent weaknesses in such joints.
CFRP components are attached to metal with an innovative design that requires no threaded inserts.
Developing the CFRP technology completely in-house now allows Lexus the unique opportunity to deploy this dramatic weight savings technology to future Lexus models.