Presentation on theme: "Plastics vs. Metals in Automobiles Greg Boehm Kendall Chapman Gordon Clarke II Gary Gomlak April 10, 2001."— Presentation transcript:
Plastics vs. Metals in Automobiles Greg Boehm Kendall Chapman Gordon Clarke II Gary Gomlak April 10, 2001
General Overview History / Background General Design Characteristics Select Parts for Comparision –Fuel Tanks –Interior / Exterior –Cooling and Air Intake Systems
History –Polymers first use in vehicles Tires. Rubber in bumpers. (1940’s) Electrical wiring. –Interior (late 60’s – 70’s) Upholstery cushioning. Dashboard / Instrument Panels. Electronic components and housings.
History –Exterior Body panels – from composites (fiberglass) on the Corvette. Bumper fascias on almost all models today. Compression molded polyester body panels. –Highly sophisticated polymers, such as injection molded nylons, are now being developed for mechanical and operational systems.
General Design Characteristics Mechanical Strength –Weight –Temperature Material Cost and Manufacturability Coatings Applications Recyclability
Mechanical Strength Temperature –Plastics making inroads to high temperature engine accessory applications. Corrosion Weight Permeability –Issue in fuel and high pressure systems.
Materials Cost Biggest barrier to plastic in automobiles. Raw material cost. –Basic polyethylene to specialty plastics. Strength and weight to cost ratio. Cost in manufacturing. –Challenge in high end parts. Recyclability.
Coatings Applications Materials and manufacture. –Economical raw material costs. –Lower “tooling” costs. Coating Process. –Greatest expense lies with paint materials and their adhesion difficulties with plastics.
Introduction to Fuel Tanks Terne-coated steel mainstay for automotive for automotive gas tanks. Drivers for change include: 1.Legislation 2.Permeability 3.Weight 4.Safety 5.Cost
Plastic Fuel Tanks Since mid 1980’s plastic replacing steel fuel tanks. HDPE is the resin of choice for plastic gas tanks. Barrier technology enables plastic fuel tank manufacturers more stringent emission standards. Some see multi-layer tank technology as the answer to stricter emission standards
Steel Fuel Tanks Currently a steel substrate coated with zinc- nickel or terne. Stainless steel tested but are difficult to form without severe breakage. Also very expensive. Testing painted galvanneal found it effective for resisting corrosion on both sides of the tank.
Performance Attributes Manufacturability Terne plate holds a cost advantage over HDPE. Cost not the only driver: reliability within the total fuel system. Plastic tanks need to be chlorinated or fluorinated to retard permeation. Can be toxic if mishandled.
Performance Attributes Features and Weight Plastics have the ability to meet packaging constraints. Design engineers have flexibility in the car design without worry of fitting the gas tank Plastic tanks can boast of weight savings of up to 30%. New permeability requirements diminish weight savings.
Performance Attributes Safety and Corrosion Ability to meet crash requirements is the key. Plastic considered safer because they are seamless. Plastic are also not a source of sparks. Retard heat transfer to the fuel. When deformed they have the ability to rebound. Thermal properties are an issue in determining material.
Interior Polyurethane foam has long been used due to design and economic benefits. ABS plastic instrument panels reduce production costs and weight of autos. Seamless, single units are easier to assemble and install. Steering wheels made from molded vinyl resins or pigmented urethanes.
Interior HVAC vents and control consoles produced from ABS and polypropylene resins. Key parameters to all plastics in this area are: –Reduced weight. –Reduced noise and vibration. –Reduced manufacturing costs.
Exterior Materials and manufacture. – Cost effective. Highly filled and cross-linked polyesters. Premium mechanical Properties. Compression molding process. Coating process. –Unique problems to solve. Adhesion problems with paints. High cost of coatings and “off-line” preparation.
Cooling and Intake Systems Cooling Systems –Radiator end caps –Radiator fan –Water pump Air / Fuel Intake Manifolds –Fuel injectors Temperature resistance and cost drivers.
Cooling Radiator end caps injection molded Nylon –30% weight savings. –Molded into complex shapes to save space. –High resistance to corrosion and temperatures. Water pumps also made of Nylon. –Withstand high pressures. Radiator fans from Nylon. –Mechanical strength to avoid warping. Short molding cycle for Nylon.
Air / Fuel Intake Systems Air intake manifold –Nylons again used for its flexibility in design. –Smooth interior surfaces to allow for better flow of air into engine. Fuel intakes now emerging with integrated injectors, filters and sensors. Cost is still a barrier to widespread use.