Figure 3 compares relative part weight and part cost of various competing materials, such as steel, high-strength steel, aluminum, carbon composites, etc. Carbon composites have the highest weight reduction potential (up to 60 percent lighter than steel), but is by far the most expensive alternative (~500 percent costlier than steel).
In automotive, the current usage of carbon composites is limited to sports, electric and high-performance cars with annual production of less than 10,000 units. However, OEMs are targeting the use of carbon composites in high-volume cars with annual production of 20,000 to 40,000 vehicles. High fuel efficiency (54.5 mpg target by 2025), emission concerns and government policies are generating pressure on OEMs to manufacture lightweight vehicles. Here, carbon composites have a large role to play and can prove to be the game changer. However, price of carbon fiber is a big concern to automakers.
Since the introduction of the Kyoto Protocol, an international agreement that sets binding emissions reduction targets, the use of lightweight materials has offered a monetary benefit. This justifies increased use of lightweight materials in the future. There is a potential of approximately 40 to 60 percent cost reduction in carbon composite parts, with improvement in precursors and advancements in carbon fiber manufacturing processes as shown in Figure 4.
Industry strives to improve manufacturing processes and reach a low cycle time – one to two minutes. There have been numerous successful landmarks in minimizing the parts manufacturing cycle time. In 1981, McLaren introduced the F1 car with a chassis made of carbon composites using prepreg layup. The company took 3,000 hours and 100 employees to build the chassis. When the Mercedes SLR was introduced in 2003, that figure decreased to 400 hours. In 2011, the manufacturing time plummeted to 4 hours for the MP4 12C monocell using the RTM process.
To contribute further, Plasan Composites joined with Globe Machine Manufacturing Co. to develop the pressure press process, which has a parts cycle time of 17 minutes. Lamborghini teamed with Callaway Golf on a forged composite process, which has a parts cycle time of 8.5 minutes. Various other machine manufacturers rely on High Pressure Resin Transfer Molding (HP RTM) for fabricating parts in three to four minutes.