Material Innovations
Sorting aluminum
An advanced method of aluminum scrap sorting is under evaluation by The Aluminum Association. The association believes that aluminum usage could balloon if an automated laser sort process pans out.
"If this scrap sort process proves out, it could mean a significant increase in the aluminum content per vehicle. It's also possible that with this new sorting technique, recycled aluminum could be used for body-in-white applications," said Richard Klimisch, Vice President, Auto and Light Truck Group, The Aluminum Association.
The Aluminum Association is working with Belleville, MI-based Huron Valley Steel Corp., a metals processing firm, to obtain data on the process that uses laser-induced breakdown spectroscopy. The process begins with a particle's surface being cleaned by laser ablation. A laser pulse then hits the same spot on the particle as it moves down a conveyor belt to vaporize a small amount of material from the metal's surface, creating a small, highly luminescent plume of plasma (or ionized gas). The plume is then analyzed by optical emissions spectroscopy to determine quantitatively the metal's chemical makeup so the scrap can be sorted by alloy on a piece-by-piece basis.
Conventional scrap sorting is a slow and costly manual process. It is estimated that the first commercial sorting center, likely to go online as early as 2005, will be able to analyze and sort 45 million kg (100 million lb) of aluminum per year. "This is the HolyGrail for environmentalists: to recycle back to the highest-valued uses," said Klimisch.
For the 2001 model year, aluminum was the third most used material in cars and trucks, according to The Aluminum Association. While aluminum represents less than 10% of the average motor vehicle by weight, it accounts for about half of the vehicle's value as scrap.
"The techniques we're exploring will allow us to recapture more of the value and performance capability of the many high-quality aluminum alloys that are used in vehicles. Current separating techniques only allow us to separate aluminum from other materials in scrapped vehicles. The recovered aluminum is then recycled into castings. But the new techniques will enable us to separate cast aluminum from wrought and even differentiate between wrought alloys," said Jim Quinn, Staff Engineer, General Motors Corp. and Chairman of the U.S. Automotive Partnership, Automotive Metals, U.S. Council for Automotive Research (USCAR).
- Kami Buchholz
SSAB takes the weight out of seats
One of the many interesting aspects of Fiat's Ecobasic concept car (driven and described in detail by AEI last year) is its seat design. More information has emerged from SSAB Swedish Steel, whose high-strength steel (HSS) was used in the vehicle. According to the company, the seats comprise a closed tubular frame in cold-reduced steel with fabric stretched between the tubing sections. Since the steel tubing frame is clearly visible, it is an important part of the car's interior design. The Ecobasic seat has a mass of approximately 22 kg (49 lb), roughly half the mass of a traditional car seat.
Both the extra and ultra HSSs that have been used for the Ecobasic's seats are of the dual-phase type, manufactured by a technique that is unique to SSAB in Europe, claims the company. After hot rolling and cold reduction, the steel is annealed and rapidly water-quenched, resulting in a HSS that remains formable and weldable. Silvio Brambilla, Project Manager at Lear Corp., which designed the car's interior, said several materials were considered for the seats, but ultra HSS provided what it regarded as the best combination of price, strength, rigidity, formability, and low weight.
The use of HSS for an increasing variety of vehicle parts is becoming more common among car manufacturers, claimed SSAB.
- Stuart Birch
High-gloss plastic body panels from GE Plastics
"SOLLX is a brand new polymer for us," said Venkatakrishna Umamaheswaran, Market Development Manager for GE Plastics automotive body programs. Heralded as an alternative to painted exterior body panels, the hard-surface thermoplastic offers a molded-in-color glossy, metallic finish that is also chemical resistant. The company claims that the resin retains a paint-like gloss even after 10 years of Florida-simulated weather.
"This balance of weatherability, durability, color, gloss, and chemical resistance really hasn't been achieved (before) with large thermoplastic molded-in-color parts," said Umamaheswaran. "We've evaluated SOLLX resin against the OEM paint specifications, and it easily passed staining tests that included bee pollen, brake fluid, and gasoline." The material has been shown to protect a substrate from ultraviolet degradation, offer good scratch resistance, provide good depth of image, and maintain dimensional stability over a wide temperature range.
GE Plastics' development work with the resin has focused on three molding technologies: injection molding, film for an insert-molded decorating process, and film or capstock on sheet for thermoforming a cap layer on a molded part. Insert-molded decoration is a manufacturing process that combines screen-printing and forming of high-performance thermoplastic with injection molding. The decorated film is inserted into an injection-molding cavity, and hot resin is forced behind it to create a functional part with an integrated graphic.
A first-generation resin offering, XENOY (with polyurethane clearcoat finish) appears on MCC smart car vertical body panels in high-gloss, solid colors. XENOY has an expected weather lifespan of three to five years.
SOLLX is currently being tested and evaluated by OEMs. Umamaheswaran expects that it will appear on a vehicle within four years.
- Kami Buchholz
