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Plastics in automotive.

The automotive and the plastics industries are stepping up their joint efforts to produce better and more cost-effective cars. At least one well-known supplier is broadening and diversifying the types of services it provides to OEMS--automotive and non-automotive--both as an instrument of marketing and as a means of achieving greater efficiency. Also, now much more intense is the degree to which plastics suppliers and the Big Three automakers are working together to develop techniques and infrastructures for recycling the increasing amounts of plastics being designed into vehicles.

A larger toolbox

In the highly competitive automotive environment, the pressure to innovate and expand a supplier's usefulness and service to customers can produce unique marketing and sales tools. A major element in GE Plastics' current global strategy, for example, is to try to tap into the overall corporation's wide-ranging, diversified resource base to support its customers' productivity improvement and cost reduction efforts.

Joseph J. Reed, general manager, North American Automotive, GE Plastics, says that the corporation's broad industrial and technological skills, beyond chemistry, can be brought to bear in helping automotive customers achieve permanent cost elimination. As an example, Reed cites the high health-care costs of a GE non-automotive customer, a molder in the Southwest, and the role GE Plastics was able to play in dramatically reducing the customer's program costs, by incorporating it into GE's larger health-care group. In another example, also outside the automotive industry, a customer attempting to achieve ISO registration was about to hire a consultant at a $100,000 fee. Reed says that making available GE Plastics' know-how in ISO registration supported the customer's efforts. The result: GE was given all the business, which previously was split with a competitor. In another case, GE Plastics drew on the corporation's electrical distribution skills to help a customer reduce its large energy bills, by aiding in the redesign of the customer's electrical system.

Reed emphasizes that a major marketing and sales approach of GE Plastics in the automotive industry, which increasingly stresses the need for across-the board improvement, is to maximize its usefulness through a sharing of its diverse strengths as a corporate entity and to transcend the typical areas of material supply and design assistance. The goal is to make available an expanded functional "toolbox" that will help customers in their overall cost-reduction efforts, both in the early design stages and at the factory production levels.

A dedicated group, called Customer Productivity Programs, working in tandem with GE Plastics' commercial teams, now focuses on customer identification and needs assessment to achieve productivity improvements and cost reduction within a customer's organization.

Reed says that "millions of dollars have been and will be saved by our customers, both inside and outside the automotive industry, through our bringing the capabilities of our diverse businesses to bear, as appropriate, in helping to reduce total systems or operations costs."

Still a way to go

In spite of their proven advantages and many successful applications, plastics for exterior body panels are still a "tough sell" and will continue to be as long as the materials must buck up against automotive assembly lines that are geared to steel. That's the opinion of Subi Dinda, manager, Advanced Manufacturing Technology Development, Chrysler Corp. Dinda's comments are typical of those of numerous people in the industry who, like him, value the benefits of plastics but contend that coping with existing assembly infrastructures can sometimes negate the gains.

Dinda says that mixing steel and plastic on a vehicle in the same assembly process, particularly regarding on-line temperature compatibility in the E-coat ovens plus other special attention that must be given to compensate for the differences in temperature coefficients, often gets more complex than anticipated, especially at an assembly rate of 65 to 70 cars per hour. He points out that even the Du Pont Bexloy K550 glass-reinforced polyester fenders on the new Chrysler LH series, notwithstanding the fact that they go through the E-coat ovens at 350|degrees~F to 400|degrees~F on-line with the rest of the steel body, still require special attention.

Dinda adds that the total cost of the plastic body panels, including tooling investment and cost of secondary assembly fixtures, is indeed significantly lower than for steel, although the piece cost is appreciably higher. The steel industry, however, is working hard to reduce tooling and fixture costs, for high- as well as low-volume production. Instead of, typically, seven die-stamping stages, for example, in only the last few years the cycle capability has been cut to four or five steps. In the attempt to reduce tooling costs for low-volume steel production, efforts include different processes such as hydroforming, and reducing machining requirements by incorporating cast elements. Dinda surmises, with bottom-line cost considerations still paramount, that plastics may be getting stiffer competition from steel, even in the 50,000 to 100,000 vehicle niche markets, where plastics have been able to build solid cost advantages.

Granting the fact that materials suppliers have done an outstanding job of early interfacing with OEMs to help solve development and application problems, Dinda feels there is still a perception gap among some suppliers, because of insufficient on-line experience, relative to the complex problems of putting cars together. He also sees differences in awareness of quality. While Dinda applauds the molders' achievements in turning out parts of high-quality appearance, he nevertheless holds that differences in understanding still arise between molders and OEMs as to what is acceptable as the automakers try to interpret customer expectations and demands.

Infrastructure for recycling

Plastics recycling has become one of the front-line issues in the automotive industry. Already, about 75% of every scrapped vehicle in the U.S. is recycled: Its useful components are stripped, the remaining hulk is shredded, the ferrous and nonferrous metals are separated. Although plastic residue from vehicles represents less than 1% of the solid waste sent to landfills in the U.S. each year, it still accounts for more than a million tons of the nation's solid landfill waste annually.

For example, while about 99% of the easily separated polypropylene battery cases are being recycled, the technology of separating the other shredded residue, including plastics, glass, fluids, sealers, fabric, adhesives, paint, and rubber, as well as metals, requires further development and implementation.

The U.S. auto industry, through the Big Three's Vehicle Recycling Partnership (VRP) of the U.S. Council for Automotive Research (USCAR), now has joined up with the Automotive Group of the American Plastics Council (APC) to create an infrastructure for recycling of plastics from scrapped cars and trucks.

Richard L. Klimisch, executive director, Environmental and Energy Staff, and Irvin E. Poston, manager, Composites Engineering, GM Corp., both on the VRP's Management Committee, say that among the joint venture's major activities, in addition to developing and refining separation techniques after shredding, are studies to enhance compatibility and ease dismantling of plastic parts. They point out that some bumper systems, as an example, no need only four bolts instead of 12. Also, among the advances in recycling of thermosets, some new SMC inner panels of the 1993 Chevrolet Corvette contain 15% to 20% pulverized reinforcing filler from previous SMC panel moldings.

The recycling infrastructure is gradually building up, bolstered by strong motivation within the industry because of growing environmental pressures and cost-efficiency benefits. Klimisch and Poston relate that in a two-day (daytime) run last year at J.H. Beer's Windgap, Pa., facility, 23 GM APVs, a Corvette, and a Fiero were shredded, and the 20,000 lbs of "fluff" that was generated was pyrolized, yielding "superior" BTU-content oil and gas. The exercise substantiated an earlier smaller run of 5000 lbs. The next step will be a week-long continuous operation of the pyrolysis system. In other pilot projects, Conrad Industries, of Centralia, Wash., and Wayne Technologies, of Rochester, N.Y., also are pyrolizing plastics and recovering the high- energy-content oil and gas for reuse.

Looming on the horizon are potential amendments to the Resource Conservation and Recovery Act, passed in 1976, which may specifically target automobile solid waste. An industry concern is that the federal regulations might venture into the area of mandating car design, if only by excluding, within specific time periods, certain materials and design approaches. A goal, Klimisch and Poston say, is to get a recycling infrastructure well enough established so that perhaps the demonstrated progress would cut off federal restrictions at the pass.

Within five years, Klimisch and Poston foresee a strong infrastructure for recycling plastics, including parts such as fender liners, HVAC ducts, fan shrouds, radiator supports, and many interior components. The game plan, they emphasize, is "to pick the 'low-hanging fruit' first, the things that are easier to get at and can reduce costs now," and to keep moving upward from there.

Mobile family room

The comfort and convenience of the car's passenger compartment also continues to be a focus of design attention. The idea of making the car interior as appealing and utilitarian as a family room, with a deep sense of comfort and security, has come a long way, but the quest for optimization goes on. Louis J. Chmura, executive engineer, Vehicle Interior Systems, Plastics and Trim Products Division, Ford Motor Co., says that the desire to resolve even such mundane things as "the design and placement of a holder for the latest-size drink from McDonald's" has become fundamental in the overall emphasis on improved ergonomics.

The interest in embellishing the passenger compartment, involving many little subtleties--from the textures of knobs to the placement of the radio either above or below the climate controller--is all part of the effort to respond to feedback from customers. The result is a highly sensitive design activity that focuses on making the interior as inviting and satisfying as possible.

Squeaks, rattles, or any interior noise, even on bumpy roads, are unacceptable in the passenger compartment. Chmura says that designers attack these offending sounds with vigor. Improved designs are incorporating new fastener methods, adhesives, and innovative ways of handling plastics-to-plastics and plastics-to-metal interfaces.

Some materials are better sound dampeners than others. Chmura says that this could be a factor favoring polypropylene in future instrument panel design, especially in the integral structural ductwork for climate-control systems. Ultimately, material selection might depend as much on other factors, such as the ability to insulate sound, as on physical properties. Dynamic shaker tests are conducted on individual panels and on fully assembled cars. The parts are instrumented with highly sensitive sound pickups, aiming at getting rid of the slightest unwanted noises throughout the passenger compartment.

The impact of the "quiet movement" on design is basic--not only on material selection, but also on efforts for parts consolidation, such as combining HVAC ductwork and instrument panel structure. Other possible approaches to achieving a "no-squeak" design include attaching the instrument panel to additional structure on the car body, or adding a beam (steel tubing or plastic composite) across the car width as a structural tie for the panel. Chmura says that the impetus for interior quietness includes all vehicles, the lower as well as the higher priced luxury cars.

The car manufacturers' growing intent to build compatibility of materials into the car, as a basic assist for recycling, has also alerted the material suppliers. If, for example, an entire instrument panel were to be made of polyolefins, material modifications may be necessary to meet the requirements of the panel's individual elements, such as the skin, foam, substrate, and possibly reinforcement of a soft panel. Inevitable design trade-offs probably will require further technical developments in structural properties, temperature capabilities, and design parameters. Chmura says "as we continue trying to improve the car interiors, we keep raising the chinning bar."

The trend in all new cars to more of a flow-through cockpit-type passenger compartment creates challenges to smoothly interface the doors and console to the instrument panel, to maintain tight tolerances over a wide spectrum of operation, and to make the entire system look homogeneous in terms of grain, gloss, and coordination. Chmura emphasizes that "the test is not only the appeal to the eye and the degree of physical comfort the passenger experiences; it also has much to do with the customer's perception that he is entering a quality, secure environment."

Generational changes

The fourth-generation standard and up-level Z28 Chevrolet Camaro four-seat sport coupe, debuting mid-1993, makes extensive use of dent-resistant, rustproof body panels. The roof, doors, hatch, and spoiler assembly are made of chopped glass/polyester SMC. Front fenders and both fascias are reaction-injection-molded polyurea, reinforced with mica. The rear fascia is polyurethane, reinforced with Wollastokup. Two-side galvanized steel is used for the rear quarter panels and hood.

Similarly, the fourth-generation Pontiac Firebird features composite body panels almost everywhere, except for galvanized-steel rear quarter panels and hood. SMC (1-inch chopped fiberglass in polyester resin) is used for doors, roof, hatch, and spoiler; RIM fenders and fascias are molded of mica-reinforced polyurea, providing uniform shrink in the manufacturing process for improved fit and finish. Jack Folden, Pontiac exterior studio design chief, says Firebird's design "was greatly enhanced by the use of composite panels, and the reinforced plastic outer skins permitted more flexible shapes, and freedom to twist and flow the surfaces together in ways we never could before. A lot of the shaping of the door, for instance, would have been very difficult in sheet metal. We couldn't have gotten that plan view--that pinched-in, wasp-shaped look--without the use of these materials." The lightweight bumper beam, made from polyurethane and woven glass-mat, has a high-strength-to-weight ratio and meets all impact requirements.

SMC growth

The SMC body panels introduced in some 1993 models raise the total automotive usage to 155.6 million lbs. The SMC Automotive Alliance, comprising 33 plastics material suppliers and molders, projects a 55% jump to more than 270 million lbs by 1995. Latest examples, in addition to the extensive exterior-body applications on the new Camaro and Firebird, include the liftgate and roof on the Saturn station wagon and the hood and grille-opening-reinforcement on the high-line luxury Lincoln Mark VIII. According to the SMC Automotive Alliance, more than 1.8 million SMC grille-opening panels, up from 1.4 million in 1992, include new applications on the Ford Tempo and Ranger light-duty truck.

Steady development pace

Among the range of new developments at the 1993 SAE International Congress and Exposition, Amoco Performance Plastics spotlighted new applications of Amodel polyphthalamide (PPA) resin. Included were a camshaft sensor connector from American Electronic Components. The magnetically operated sensor monitors the position of the rotating cam in Chrysler's 3.5-liter engine for its family sedans. Other announced designs were a rollover safety valve assembly from GT Products, and two European parts--a turbocharger air cooler housing for large, Daimler-Benz trucks by Behr, Inc., and an oil filter housing by Selsdon Inc., which, unlike conventional filters, absorbs water and removes carbon in addition to the particulates that cause engine wear.

Nylon manifolds

BASF Plastic Materials and BASF Automotive Urethane Specialties displayed lightweight air-intake manifolds molded of Ultramid nylon resin. Cars that now have injection molded nylon air-intake manifolds of the BASF material are BMW, Mercedes-Benz, Porsche, Peugeot, Citroen, Renault, and Volkswagen.

Interior components molded of CFC-free polyurethane systems, including steering wheels, instrument panels, headliners, and door panels, also were shown. The recent switch by Dayton Polymeric Products, Inc., to water-blown polyurethane foam molded steering wheels for heavy trucks and off-the-road equipment is the first step in the company's program to eliminate CFC-blown systems from its polyurethane foam manufacturing operations.

The list of exterior applications for unpainted ASA parts continues to grow. BASF says that many cars now have unpainted side-view mirror housings that are injection molded of Luran S ASA resin. Cowl vent covers are another ASA application on more cars. The '93 Jeep Grand Cherokee has a cowl vent cover molded of Luran S ASA resin.

Scrap recycling

Saturn, in cooperation with its supplier, the Automotive Materials Group of Dow Plastics, has developed a method for recycling painted and unpainted scrap of Pulse B-250 PC/ABS resin from exterior door panels and other applications into rocker panel support brackets. Robert D. Albert, vice president, Automotive Materials Group, Dow Plastics, foresees plastics recycling as inevitably building momentum and becoming standard practice in day-to-day operations. He says that "we are only scratching the surface in implementing design techniques, including combining of different materials, that will enhance performance and functionality and decrease cost, and thus stimulate growth of plastic automotive applications; further, the advanced technology will facilitate homogeneous part integration and, if necessary, separation to ease recycling."

The rocker panel support bracket is the first commercialized application of recycled Pulse B-250 at Saturn. The virgin Pulse resin, the PC/ABS painted regrind, and the unpainted regrind are fed separately into the injection molding machine. The molded parts are then submitted for laboratory characterization, component impact, and vehicle evaluations that include static load testing.

A soft touch

DSM Thermoplastic Elastomers Inc.'s new Sarlink 3140 is one of the lowest hardness (40 Shore A) thermoplastic vulcanizates (TPV) for the automotive market. Designed for applications requiring soft touch and feel, the material, with the strength and elasticity of rubber and the processability of thermoplastics, is targeted for uses such as steering wheels, radio knobs, armrests, and pads. With elongation of over 500%, the TPV maintains excellent physical properties for such a low durometer material.

Improved homopolymer

At SAE, Du Pont Automotive introduced Delrin P acetal homopolymer for uses such as seat-belt system hardware, fuel system components, fasteners, clips, and gears, with characteristics that the company says match the moldability and thermal stability of a copolymer while retaining the homopolymer's inherent stiffness and toughness. The company also said that its XTC material, which it says is electrocoat-capable (to 392|degrees~F for up to 30 min) and is "the first recyclable thermoplastic alternative to thermoset SMC and RRIM horizontal exterior body panels," now is available in commercial quantities for testing by automakers. The company also introduced its Ecofil 5 to 10 mm spherical polyester fiber clusters for automotive seat cushions as a melt-recyclable, cost-competitive alternative to thermoset urethane rubber foam. Further, Du Pont is proceeding with its proprietary depolymerization recycling processes, which renew post-consumer nylon as a complement to a system announced last year for thermoplastic polyester. The processes allow reinforcements, additives, and paint to be separated out and the resins to be returned to their pure monomer ingredients for use in virtually any market.

Under-hood durability

Responding to the growth demand for compact, durable, under-the-hood, electrical/electronic systems, Eastman Chemical Co., Performance Plastics, emphasized at SAE its Ektar FB CG007 polymer. Requirements in the automotive industry are increasing, for instance, for printed circuit boards made with electronic components capable of withstanding elevated-temperature assembly techniques, and of resisting engine fluids and other chemicals.

The 30% glass-fiber-reinforced PCT, a thermoplastic polyester specifically targeted to applications beyond the temperature capabilities of PBT- and PET-based polyesters, and a cost between PBT and PPS, offers continuous-use temperature resistance to 160|degrees~C for surface-mount-compatible electronic components, such as pin grid arrays, DIP sockets, and chip carriers. The material's high heat-deflection temperature also makes it suitable for under-the-hood elevated-temperature components such as connectors, sensors, controllers, relays, and motors.

Ignition systems, for example, are now being designed to withstand even higher temperatures. Eastman foresees opportunities for Ektar FB CG007 in thin-wall coil bobbins, with their strict requirements for dimensional precision and stability, ease of molding of flash-free parts, and ability to withstand corona discharge.

All-polyolefin instrument panel

Exxon Chemical's exhibit at SAE promoted the concept of the all-polyolefin instrument panel, displaying polypropylene skin, retainers, consoles, glove-box doors, and finished systems. The Chrysler LH instrument panel, with an integrated knee bolster, consolidates four parts into one. All knee bolsters on the new LH models--the Chrysler Concorde, Eagle Vision, and Dodge Intrepid--are made of lightweight Taffen STC with 40% glass content.

Also featured was an all-polypropylene bumper system, with a Taffen bumper beam; Mytex TPO and Exxtral Reactor TPO fascia; and polypropylene foam energy absorbers, which underwent 5 mph testing in the exhibit. The company says that when components were subjected to 200|degrees~F for 17 weeks, to simulate two years of normal temperatures, Mytex EPP lost just 2% of its impact strength, compared to much higher loss levels for competitive materials. Exxon also adds that in sound measurements taken in an acoustical chamber for interior components, airborne sound attenuation was notably improved over competitive materials.

Better coupling

Hoechst Celanese's SAE exhibit included Celstran PPG40-03-4 heat-stabilized, long-strand glass-fiber reinforced polypropylene, with an improved chemical coupling agent, for under-the-hood applications; and Celadyne Deflection Pad polybenzimidazole (PBI) high temperature (630|degrees~F), high load capacity and compressive strength, low-friction thrust bearings and washers. The latter is based on a joint effort of the designer, KMC, Inc., and Hoechst Celanese's Performance Parts Division; significant enhancement of the fluid film "wedge" of lubricant between bearing surfaces is achieved. Also, new applications for the company's Trevira Spunbond polyester fiber mat demonstrate improvements in the impact resistance of thermoset resin laminates.

Glass-fiber composites

Among the products featured by LNP Engineering Plastics at SAE was Verton MFX, a new series of injection moldable long-glass-fiber composites for applications such as mechanical components, fan shrouds, load floors, bumper structures, component housings, and brackets. Verton MFX 700-10, a 50% long-glass-fiber reinforced polypropylene, for example, is being projected as a possible replacement for stampable sheet, short glass fiber composites, and metal fabrication methods.

New polyurethane filler

The materials highlighted at SAE by Miles Inc. included a Bayflex 110 RIM polyurethane system incorporating a new low-density filler, as a replacement for conventional, more expensive, and heavier glass reinforcements; and an experimental Bayflex 95 polyurethane system, which the company says may provide fascia cost savings of about 30%, made possible by chemistry advancements. Also on the horizon for fascia production is a Bayflex 180 prepolymer system, which is expected to maintain the cost competitiveness of the other new RIM systems while providing performance and processing advantages.

Miles's Polymers Division introduced Bayfill EA (energy absorbing) polyurethane foam systems. The new semirigid products include Bayfill EA-60 and EA-70 systems. The latter has been specified for a 1995 model vehicle, in which the lightweight, low-cost material will be molded in-place around a new-technology, non-steel beam to create a cost-efficient bumper module.

As a mid-1993 model year production change for Chrysler's Dodge Viper RT/10 sports car, front and rear bumper beams made of Miles's high-strength, low-viscosity Baydur STR/C-400BB SRIM polyurethane system are replacing steel beams. The beams utilize an SRIM reinforcement technique recently developed by Davidson Exterior Trim, a subsidiary of Textron Inc. The 7.6-lb structural RIM beams are more than 50% lighter and provide 5-mph impact resistance.

To further enhance the smoothly rounded, high-technology appearance of the interior of the Lincoln Mark VIII, Ford has upgraded 27 hard plastic components by using a special-effect, two-component polyurethane coating that provides a soft-luxurious feel. The "Soft-Suede" coating, supplied by the Sherwin-Williams Co., is applied to thermoplastic parts ranging from the car's two air-bag covers to the instrument panel trim and center console. Also highlighted at the Miles exhibit were recycling technologies under development for thermoplastic and thermoset materials.
COPYRIGHT 1993 Society of Plastics Engineers, Inc.
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Title Annotation:automobile industry
Author:Wigotsky, Victor
Publication:Plastics Engineering
Date:Apr 1, 1993
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