Plastics vs Automobile Industry

From bumpers to fuel tanks, lightweight plastic gives cars better gas mileage and allows engineers more freedom in their designs. Traditionally, metal alloys were used in manufacturing automobile components, however, plastic has several advantages that allows it to outperform metal. Plastic offers a variety of practical, cost effective alternatives as well as advantages over traditional automotive production materials. There are many characteristics in which plastic parts are superior to steel, and this paper has touched on a few of these areas. The 4 major characteristics can be summarized as follows3:

1)1) Weight – Because plastic can weigh 6 to 8 times less than certain metal parts, using

it to reduce the weight of the car helped to make it more fuel efficient.

2)2) Easier to Produce – Plastic is generally more expensive but easier to mold and

produce/re-fabricate.

3)3) Design Flexibility – Allows engineers to have greater freedom in styling, building

and placing components.

4)4) Parts Consolidation - One plastic part usually replaces the function of several metal

pieces.

Analysis for Gas Tanks5

Advantage

Disadvantage

Steel:

Terne-Coated Steel

volumes

1)1) Shape flexibility

2)2) Ineffective corrosion

protection

Electrocoated Zn-Ni

1)1) Low cost at high

volumes

2)2) Recyclable

3)3) Effective against

corrosion

4)4) Permeability

1)1) Weldability

2)2) Shape flexibility

Hot-Dipped Tin

1)1) Low cost at high

volumes

3)3) Effective against

corrosion

4)4) Permeability

5)5) Weldability

1)1) Shape Flexibility

Stainless Steel

1)1) Corrosion

2)2) Recyclable

1)1) Cost at all volumes

3)3) Permeability

Plastics:

HDPE

2)2) Low tooling costs at

low volumes

3)3) Weight

4)4) Corrosion resistance

1)1) High tooling costs at high

volumes

2)2) High material cost

Multilayer and Barrier

HDPE

1)1) Shape flexibility

1)1) Higher material cost

2)2) Harder to recycle

The major disadvantage of a plastic is Recycling. Recycling has now become a mainstay in society due to tighter environmental measures. New processes enable manufacturers to reuse scrap plastic and recycle used plastic cost-effectively. In a sense, this paper has been a discussion of how plastic is better than metal.

1.1.www.ai ag.org

84, 1988, AICHE, New York, New York, 1988

5.5.www.tms.org /journals/

6.6. Plastic processing for the automotive engineer, Society of Automotive Engineers,

1967, 29p

7.7. Automotive engineering, Society of Automotive Engineers, v80, no.11-v 105; Nov.

1972-Dec. 1997

8.8.http://www.plastics- car.com/spotli ght/auto_slideshow.html

9.9. Timothy T. Maxwell and Jesse C. Jones, Alternative Fuels: Emissions, Economics

and Performance (Warrendale, PA: Society of Automotive Engineers, 1995), pp. 29-42.

10.10. Robert Q. Riley, Alternative Cars in the 21st Century (Warrendale, PA: Society of

Automotive Engineers, 1994), pp. 173-176.

11.11. Bundy International, "Fuel Supply Systems for a Healthier Environment", ed.

Michael Scarlett, Automotive Technology International '94, pp. 37-40.

12.12. "Plastic Bounces Back in Fuel Tanks," Automotive News (January 30, 1995).

13.13. Delphi VII Forecast and Analysis of the North American Automotive Industry (Ann

Arbor, MI: Office for the Study of Automotive Transportation, University of Michigan

New Plastics and the Automobile

Until 1971, Australians in the Outback did not have to pack a barbecue if they went on a camping trip in their Land Rover. They had discovered that the Land Rover's wire-mesh radiator grille worked just fine for impromptu barbecues. In 1971, Land Rover introduced the Series 3. As many shocked, and then hungry, owners discovered when they tossed their new Series 3 grilles onto the open fire, the grille was made of plastic.

Nearly 30 years later, consumers discovering plastic parts in their vehicles should not be so shocked. The Association of Plastics Manufacturers of Europe (APME) reports that 1.7 million t (1.9 million ton) of plastics were used by the automotive industry in Western Europe in 1997. According to the American Plastics Council (APC), the average 1999 North American car weighed about 1450 kg (3200 lb) and had 117 kg (257 lb) of plastic, which is expected to grow to about 142 kg (313 lb) by 2009. Approximately 1.8 million t (2.0 million ton) of plastics were used on North American cars and light trucks in 1999, and experts predict that amount to increase to about 2.4 million t (2.6 million ton) by 2009.

Information was provided by the American Plastics Council; the Composites Fabricators Association; the Oak Ridge National Laboratory; the Office of Transportation Technologies; the Society of Plastics Engineers; and the U.S. Council for Automotive Research.

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  Why plastics?
  
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  Why now?
  
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  Exterior
  
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  Interior
  
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  Under the hood
  
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  What's next?
  
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  New Plastics and the Automobile
  Why plastics?
  
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  The 2000 Mustang SVT Cobra R went into production in early spring with carbon-fiber air ducts that cool the front brake rotors. The Ford Equator concept truck features bumpers, fenders, wheel wells, and lower trim panels made of Kevlar.

  The term "plastics" encompasses organic materials (carbon, hydrogen, nitrogen, etc.) of large molecular weight that can be shaped by flow. The term usually refers to the final product, with fillers, plasticizers, pigments, and stabilizers included, versus the resin-the homogeneous polymeric starting material. Plastics are polymers, which are created by the chemical bonding of many identical or related structural units.
  
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  Polymers that contain primarily carbon and hydrogen are classified as organic polymers, including polypropylene (PP), polybutylene (PB), and polystyrene (PS). Other elements found in the molecular makeup of polymers include oxygen, chlorine, fluorine, nitrogen, silicon, phosphorous, and sulfur. Polyvinyl chloride (PVC) contains chlorine. Nylon contains nitrogen. Teflon contains fluorine. Polyester and polycarbonates (PCs) contain oxygen. Polymers that have a silicon or phosphorous backbone, instead of a carbon one, are considered inorganic polymers.
  
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  A thermoplastic is a polymer in which the molecules are held together by weak secondary bonding forces that can be softened and melted by heat, then shaped or formed before being allowed to "freeze" again. The heating and cooling processes can be repeated many times without significant chemical change. A thermoset is a polymer that solidifies irreversibly when heated due to a chemical reaction involving cross-linking between chains. Thermoplastics in general exhibit better flexural and impact performance and superior resistance to solvents; thermosets tend to have better compressive strength and abrasion resistance and significantly better dimensional stability.
  
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  Composites consist of a reinforcing fiber in a polymer matrix. Polyester, vinyl ester, and epoxy resins are most often the matrix of choice. Composites essentially combine the strength and rigidity of metals and the light weight, flexibility, and corrosion resistance of plastics. Henry Ford began experimenting with composites around 1940, initially using compressed soybeans to produce composite plastic-like components. As can be seen in the lead photo from 1941, the phenolic trunk lid was strong enough to withstand an energetic Ford armed with a sledgehammer.
  
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  According to the Composites Fabricators Association, about 65% of all composites produced currently use glass fiber and polyester or vinyl ester resins, and are manufactured using an open molding method. The remaining 35% are produced with high-volume manufacturing methods or use advanced materials, such as carbon or aramid (polyamides such as Kevlar) fiber. Carbon fiber is primarily in use in the motorsports and aerospace industries because of its significant strength and frictional performance. The main reason for its limited use in the automotive industry has been its high cost, though one recent use is in Ford's 2000 SVT Mustang Cobra R. Air inlets designed into the Cobra R's fog light bezels are used to provide extra cooling for the front brakes. Air ducts run from these inlets to special carbon-fiber heat shields fitted around the inside of the brakes to intercool the rotors. The heat shields were developed by Multimatic Motorsports and were used by 1999 Cobras in the Motorola Cup racing series. The main automotive application for carbon fiber continues to be for moving parts in the engine and transmission.
  
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  Aramid fibers are used in moving parts where lubricity and dimensional consistency are more important than strength or rigidity, such as clutch belts and grease-free ignition switches. However, the Ford Equator concept truck displayed at the North American International Auto Show (NAIAS) in January featured Kevlar bumpers, fenders, wheel wells, and lower trim panels, making the parts resistant to stone damage and what Ford confidently described as "nearly indestructible."
  
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  Polymers have very distinct characteristics, but all have things in common. They are resistant to harsh chemicals; provide both thermal and electrical insulation; offer good noise, vibration, and harshness (NVH) characteristics; offer design flexibility; have an excellent strength to mass ratio; and offer a variety of production options. They can be molded into the body of a car, or mixed with solvents to become an adhesive or paint. Elastomers and some plastics are very flexible. Other polymers can be foamed, like PS and urethane. Polymers seem to have an unlimited range of characteristics and colors, with inherent properties that can be enhanced by a wide range of additives to broaden their uses.