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Automotive plastics.

Charles Haddad, manager of Ford's advanced engineering design staff , may not be a full-time iconoclast, but an icon he would like to see destroyed is the one that inhibits revolutionary change in automotive architecture. Haddad advocates tapping into and integrating varied new and unused technologies; his goal is to develop a quality, low-cost car for people with low incomes, a population group he considers to be the world's largest potential car market. In the process, he believes, the innovations would also be transferred to car lines at the upper end, improving corporate profitability.

Automotive engineers are typically cautious, often with good reason, when it comes to radical changes. Haddad, however, sees inherent penalties in being overcautious, given the potential benefits that might otherwise accrue. Rather than being applied to the consumer's advantage, the possible advancements instead wait in the wings, unutilized or, at best, underutilized. Haddad wants to speed things up. He traditionally has been impatient with the automotive development system's powerful, entrenched protective mechanisms, including a multileveled people barrier, which prevent more rapid responses to design opportunities.

Haddad's vision is of a low-cost quality car that combines existing automotive technology with proven capabilities from other fields. He develops some of the ideas himself, but mostly he incorporates ideas from others at Ford and from suppliers. He is now starting to see his ideas materialize. He is generating attention at Ford for ideas that he says could reduce a car's investment and manufacturing costs by as much as 60% to 80%. Interest and design support from a few key Ford groups--such as Manufacturing Development Center, Product Design and Engineering Staff, Electronic Systems and Research Staff, and Advanced Power Train Engineering Offices--are easing the job. "We are no longer alone in this effort," Haddad comments. "It feels good to have support."


The light now at the end of the tunnel may soon reveal a prototype intermediate-size, sporty, low-cost Ford concept car, patterned after the Thunderbird or Mustang. Varied proven technologies will be exploited to expand functionality and to slash assembly requirements.

A new type of compact power train, which may be ready for display at the January 1991 International Auto and the February SAE shows in Detroit, will permit more interior room relative to car size. With a ducted cooling system, engine heat will be dumped from the sides of the car, instead of through the engine compartment. The anticipated result will be a 50 [degrees] F to 75[degrees] F drop in under-the-hood temperature.

The car will be built around an extruded aluminum space frame, which will cut about 200 lbs, compared with a steel space frame. Haddad expects that since the order for extrusion dies is imminent, the completed space frame could be ready to be displayed at the Detroit shows. The aluminum extrusions will eliminate the blanking, forming, and trimming, and the fixtures for 3500 to 5000 spot welds, typical of a conventional or space frame steel construction. Asserting that pound for pound, aluminum's energy absorption capability is even better than steel's, Haddad sees no compromise at all in the new structure's crashworthiness.

Haddad points out that cosmetic changes in the plastic skins could be retooled for about $40 million. For similar changes in steel panels, the tab would be about $200 million.


Plastic exterior panels and their attachments to the car are now under development. Haddad likens the assembly concept to that of a "Tinkertoy," using snap-fits, adhesives, and newly designed connectors that provide freedom in the degree of frame and panel engagement to assure accurate mounting without need for precision calibration. The concept, he maintains, will ensure that the panels will be in their correct "fit and finish" position even in the event of slight deviation in the space frame.

New connector designs will give the body panels freedom to thermally expand or contract without need for slip joints. The snap-fits, adhesives, and Velcro-type plastic fasteners to be used for attaching the plastic panels to the aluminum frame will reduce fastener requirements from about 4000 (including spot welds) for a steel space frame to only 50 or 60 joints and fasteners.

Ford currently is working with Bayer/ Mobay Corp. on the application of exterior plastic materials for the concept car, and Haddad expects that the initial vehicle will feature polyurea exterior body panels. However, he concedes, looking down the road, he is partial to thermoplastics. He also foresees thermoplastics for horizontal panels, possibly using an integrally molded inner glass fabric reinforcement for added stiffness.

Haddad's overall approach to car design and manufacturing also includes reducing the complexity and cost of the typical automotive plant. For one thing, the traditional zinc-rich E-coat, with its high, 400 [degrees] F-plus bake temperatures, and conventional paint shops and their emission problems, would be scrapped. In one system, developed by Avery Co., a prepainted film is blanked into a preform, which is placed in the tool when the exterior part is molded with a compatible material. A high-gloss, composite Class A surface is produced, without need for a separate paint line.

Many opportunities still exist for parts consolidation, modular assemblies, and streamlining the car interior to provide more space and improved function. There are barriers to overcome, but Haddad hopes that in the fall of 1991, a drivable low-cost car with aluminum space frame and all-plastic body panels will be shown at the Frankfurt Auto Show in Germany. As Haddad would agree, ideas are only as good as the dedication and perseverance that support them.


Chrysler Corp.'s Saad Abouzahr, technical program manager, Advanced Development, says that an extensive effort is under way on development and application of plastic body panels and fenders for upcoming models. Consistent with Chrysler's position requiring on-line paintability of plastic exterior body parts, fenders of Du Pont's Bexloy K550 are being evaluated on a 500 vehicle minivan fleet. The fenders have been painted on-line with the steel bodies. The material now is in production for the valance panel, between the front bumper and grille, for Chrysler's 1991 Mexican D pickup truck. Abouzahr comments that with design innovations, horizontal panels for deck lids and hoods could be made of thermoplastic or a combination of thermoplastic and thermosetting materials. "Sheet molding compound currently is the only material that works for horizontal panels," he says, "but much finishing is still required to get a Class A surface." Because of its low investment requirements compared with compression or injection molding, resin transfer molding (possibly using epoxy or epoxy-nickel shell tooling) is being considered for both vertical and horizontal panels for some low-volume cars (less than 5000 vehicles/ year), using low-profile thermosetting polyesters. The parts would be painted off-line.

Chrysler is also moving into rubber-modified polypropylenes with molded-in accent color as a replacement for RIM polyurethane for fascias of most of the company's low-line vehicles for the mid-1990s. The main incentive is cost savings. Expanded polypropylene foam and rolled steel bumper beams will replace hydraulics as a cost-effective energy management system. RIM polyurethane will still be the material of choice for fascias on the company's upper-end vehicles'

John Fillion, supervisor, Interior Plastics and Soft Trim, says that polypropylene and polypropylene-based products with molded-in color are being aggressively considered, for cost and weight reduction, as possible replacements for painted styrenics, notably ABS, and, in some interior areas, for polycarbonate blends. Potential uses include parts such as A and B pillars, consoles, the lower portion of the instrument panel, and passive restraint knee blockers." Parts such as glove box doors and steering column covers, typically now painted, also are expected to be specified for molded-in color wherever possible.

Fillion adds that a move into higher crystallinity polypropylenes is being considered, with a preference to select one grade to cover all requirements. The possibility is that a 200,000 psi modulus material would replace a 130,000 psi general-purpose grade now being used. For higher temperature areas, a mineral- or glass-filled polypropylene would be chosen, or, if needed for maximum sun load conditions (such as in the instrument panel area), a "more engineered" polypropylene formulation would be selected.

Leo Ang, supervisor, Exterior Plastics and Structural, says that a variety of ongoing programs involve special composites for load-bearing uses, including pre-forms for structural RIM and transfer molding of vinyl esters. Other programs focus on reducing under-the-hood temperatures and integrating parts. Chrysler is evaluating fuel rails, composite valve covers, and nylon and phenolic intake manifolds, using a concept "other than" the melted core technique.

Another active program at Chrysler is an all-plastic front and rear seat molded of integrally colored nylon, intended, possibly, for use in mid-1990s passenger cars and trucks. The seat program is based on a modification of an original Bayer/ Mobay design.


The major trend in automotive interior design is to treat the interior space as an integrated system rather than as individual components, says Lou Chmura, executive engineer, Plastic and Trim Products Division, Ford Motor Co. "The direction now is to have elements such as the instrument panel, consoles, and door trim panels interface and flow into each other like a coordinated cockpit, with the components complementing one another. The goal is to make the 'cockpit' user-friendly, for example, the graphics more readable, so that the overall ergonomics of the space provide maximum convenience for the passengers."

Chmura emphasizes that interior design is a new ball game, involving a need for maximum component and materials integration. The cellular phone, which Chmura expects will grow at a high rate as another interior function, is an example. Now available as an option in the Ford Lincoln, the amenity reflects the desire to make the interior as customer oriented as possible.

Taking out weight is another major concern. Chmura says that a substantial amount of steel was added to the instrument panel to provide structure and energy management for knee bolsters, and the steering column and front passenger air bags. "We are now looking for ways to remove the redundancy of parts behind the instrument panel through use of engineering plastics," Chmura says. "The plastics would provide structure and would permit integrating separate components such as the climate control ductwork with the panel. The goal is to clean up the panel's underside to reduce weight and complexity. There is a driving force for the design to follow through from the instrument panel to the door trim with an appearance that documents the integrated concept."


With recyclability now a front-line consideration, Chmura cites a pressure to use similar materials throughout the interior, such as polypropylene, to simplify the recycling process. In any event, the trend is toward softer, more plushy interiors, and at the same time controlling costs by reducing processing steps. According to Chmura, materials such as ABS and polycarbonate are very much alive" for instrument panel applications. A lot of development work is being done with easily processed polyolefin-based materials. He adds that the physical properties--for example, heat-distortion temperature of the materials--can be sufficiently modified to accommodate today's interior temperatures.

Substantial interest exists in structural polymeric composites as weight-reducing replacements for steel in instrument panels. Testing is required over an extended period to ensure that the materials will perform. "The composite structure performs differently from steel in a crash situation," Chmura points out. "Sheet metal absorbs energy by bending, tearing, and deforming in an efficient manner. Composites, which are normally less ductile, absorb energy differently. We must engineer and analyze actual parts and test them completely before incorporating them in the vehicle."

To achieve and maintain a competitive edge as a supplier, customer focus and total commitment to quality are essential. Chmura emphasizes that to meet customer expectations, it is important not to be constrained by methods put in place years ago. The objective is to streamline the entire product development process, to reduce the time required and the number of steps, and to make decisions at the appropriate times so as to eliminate late changes and thus reduce cost.


Irvin E. Poston, composites manager, GM's Advanced Engineering Staff, says the knowledge base is gradually building for evaluation of composites for semi-structural applications such as floor pans, inner and rear-end panels, and bumper beams. For primary structures, such as frame rails to replace steel, physical property data (generated in particular through the auspices of the Automotive Composites Consortium), are being developed for designs using continuous reinforcing fibers and fiber preform mat. "We are learning how to make the preforms and how to assemble them in the mold for optimum design efficiency, and how to inject the resin more effectively," Poston says. He adds that the company is generating crash and drop test and materials processing data relative to energy management and crashworthiness. "We must still, however, develop more confidence for actual structural composite applications. Epoxies and vinyl esters, with continuous glass or swirl mat, as well as chopped fibers, are being evaluated. We can produce viable primary structures now, with reinforcements such as aramid and graphite, but they would be very expensive. From a practical, cost-effective standpoint, the structural composite technology in automotive is still some years away from broad realization. Leaf springs are here now, and composite floor pans and individual selective structural composite components may be in production cars by the year 2000. A complete frame as a primary structure is further in the future, not really imaginable within the next ten years."

Possibly spurred by the company's newest line of minivans, the all-plastic-bodied APV, and since GM is the largest user of composites in the auto industry, the Advanced Engineering Staff continues its research on the pyrolysis process, in which materials are decomposed by extreme heat in the absence of oxygen. The emphasis now is on SMC waste management, with a later focus expected on the RIM materials. Poston says that once the process reaches SMCs thermal decomposition temperature of 140 [degrees] F using external fuel, the system becomes selfsustaining from energy produced by the pyrolysis. SMC contains more than enough energy to sustain the process, and the excess gas and oil can be recovered.

Some of the potential uses of the SMC residue include filler in SMC formulations and other polymer composites such as RIM formulations or adhesives, as well as filler in other materials such as concrete and roofing shingles. Poston comments that current results are encouraging, but further testing and evaluation must take place before pyrolysis can be considered a viable means of waste management.


GM's Inland Fisher Guide injection molding plant in Syracuse, N.Y., with 134 machines ranging from 700 to 3300 tons, and a volume of 80 million lbs/yr, is the third largest in the U.S. It has traditionally been a molder of interior and exterior trim parts for the company's diverse car lines. About two thirds of the plant's volume has been equally divided between molding polypropylene and ABS, with the remainder going basically to parts made of nylon, polyurethane, and polyester. The plant produces less than 5% scrap, all of which is recycled; the regrind ratio is kept at under 10%. Automatic part removal, with pneumatic, ball screw, and belt-driven robots, is incorporated on 47 of the machines.

Now there is a new kid on the block. For the first time, the plant is molding front and rear fascias, on 2700 ton machines, and utilizing robotic part unloading. Made of Himont's HiFax thermoplastic olefin with contrasting or accenting, rather than matching, colors, the fascias for GM's Chevrolet Cavalier sedan, coupe, and station wagon net a 33% cost saving over painted RIM polyurethane. The savings are derived largely from the elimination of painting steps.

Part-to-part cycle time for fascia production is 100 seconds. At a projected production rate of 300,000 vehicles per year, the application will account for about 5 million lbs of the Syracuse plant's volume. GM anticipates an expanded use of fascias with molded-in color in future vehicles.

To reduce inventories and costs, the twenty-three polypropylene and twenty-one ABS colors used for the interior parts, and the silver, white, gray, and black colors for the fascias are all achieved by color blending at the injection molding machines, rather than by use of integrally colored pellets.

Uncolored resin, fed directly from rail cars to the machines, is blended with color concentrate at the throat of each machine. The proportional weight of resin and color concentrate are continuously monitored by a precision weighing system under statistical process control. By using weight as the controlling element, and through regulation of the upper and lower limits of the standard deviation values, the weight control system, developed with the aid of Robert Horn, CPC quality control engineer, is able to minimize sink marks, flow lines, and warpage in the parts.

Because of the plant's tight rein on quality, rooted in supplier certification of incoming materials that is supported by statistical data for every lot shipped, spot checks by selective physical property testing are done no more than once every seven or eight weeks. The system is fundamentally based on the established credibility of the supplier and the ongoing customer/supplier relationship of mutual confidence in the day-to-day operations established to maintain the required specifications. The relationships also are instrumental in the continued development of materials improvements that enhance such properties as flow rates and UV stability, and permit part simplification by elimination of metal inserts where they were previously necessary.

Recent acquisition of a coordinate measuring machine eliminates the need for manual dimensional inspection, reduces gaging time, assures repeatability in evaluation of prototype molded parts, and permits collection of statistical data for verification of processing conformity or necessity for system modifications. A similar installation for automated inspection of parts and tooling is scheduled for January 1991. Other plans include addition of an 1850 ton Husky tandem injection molding machine in the first quarter of 1991, which will save space and reduce cycle times in the manufacture of rocker panels and body side moldings of filled polyurethane.

The GM Syracuse plant ships an average total of 330,000 lbs/day of molded products in 1800 returnable containers, 700 nonreturnable cartons, 17 railcars, and 39 trucks. Selections from over 5000 different parts are shipped among twenty-three GM car and three truck assembly plants, as well to component plants, and service and distribution centers. A network of twenty-seven silently running self-driven, guided vehicles, controlled by on-board computers regulated by a centralized staffed station, are used for movement of purchased parts, packing materials, regrind, finished products, color concentrate, and trash. Considering the high volume and the diverse range of activity, and thanks to a highly integrated training and upgrading program that encompasses the three-shift, 1500-person workforce, the GM Syracuse plant appears to run efficiently, and as quietly as a mouse.


Arco Chemical Co. says it is gearing up to provide a "marriage" of products that work synergistically to meet the total functional requirements of a subassembly. Instrument panels are one such area, in which the company's Dylark resins are used for substrates as well as for glove box doors, structural trim, vents, and grilles. An instrument panel for the Oldsmobile Toronado uses the system approach with a Dylark resin substrate, a Dytherm copolymer knee bolster, and urethane padding.


Ashland Chemical, Inc.'s Arotran RTM resin system is used for all exterior body panels on the new Lotus Elan, which is scheduled to enter the U.S. market this year. The material is also used in the heavy truck hood molded for Volvo and the removable hardtop roof for the Chevrolet Corvette.

The company's Phase Alpha SMC unsaturated polyester resin system is used to make most of the body panels for GM's new line of composite-body minivans. Ashland's Pliogrip two-part urethane structural adhesive bonds the panels to the space frame. Other applications for Phase Alpha include the body of the Chevrolet Corvette, the liftgate of the Ford Aerostar, and various medium- and heavy-duty truck hoods.


Joe Boelter, director, BASF Automotive Urethane Specialties, cites the progress in chlorofluorocarbon (CFC)-free polyurethane systems. Included are systems for foam seating, carpet backing, foam-in-fabric armrests and headrests, and SRIM interior applications, such as water-blown door panel substrates. CFC-free rigid foams for energy-absorbing interior uses are under development at BASF. Systems with greatly reduced CFC levels now are available. BASF programs to eliminate CFCs from integral-skin polyurethane foam systems for steering wheels are under way.

BASF Plastic Materials' Elastopreg thermoplastic composite sheet is used in development of designs consolidating compression molded clutch and brake pedal assemblies, and also in bumper, modular front end, and seating systems.


Dick Dolinski, vice president, Automotive Materials Group, Dow Plastics, says that with the exception of platforms such as the GM Corvette, GM APV, and BMW Z-1, the interior of a typical car features about 40% plastic, and the exterior only about 11%. Under-the-hood applications are about 20% plastic, and plastic represents less than 0.5% of structural applications." Dolinski anticipates that plastic in bumpers, beams and fascia will increase by about 10 lbs per car. He expects growth to about 240 lbs per car by 1995, and to almost 300 lbs by the year 2000, from about 215 lbs this year, with the most dramatic growth for exterior and structural applications. Market forces, driven by new knowledge and experience with processing, will have a major impact.

Dolinski foresees a "catch-up" process for reaction injection and resin transfer molding for structural composite parts. For interiors, he predicts new styling will generate increased demand for higher heat performance without need to paint components, and accelerated efforts to modularize vehicles for parts consolidation and simplified assembly.


While there may be a trend to molded-in color fascias on lower-end car lines, the higher-line cars are staying with painted fascias. The 1991 GM Buick Park Avenue and Park Avenue Ultra use Du Pont's Bexloy V copolyester thermoplastic elastomer for front and rear fascias.

Du Pont's Bexloy K-550 for vertical body panels, which the company says is electrocoatable without added support, now is being used for 70-inch painted front-end filler panels on 1990 and 1991 Chrysler pickup trucks.

Higher performance materials, to accommodate either alcohol-based or low-volatility petroleum-based fuels in advanced design fuel systems, are among Du Pont's areas of emphasis. Future fuel handling systems may need to be compatible with a variety of cleaner burning fuels that would challenge the durability of metal and currently used plastics. Fuel lines of Teflon PTFE with a stainless steel overbraid are commercial on the 1991 Lincoln Town Car and on Ford's 1990 and 1991 Econoline van. Du Pont says its Selar barrier resin, first commercialized in Europe on the 1990 Lotus Elan, will be used commercially in North American cars in 1992. Minlon 11C40 mineral reinforced nylon is used for covers on a 1991 V-6 engine. Programs also are under way for nylon intake manifolds.


For above-the-beltine interior applications, Eastman Chemical Products Inc.'s filled impact-modified high-performance polypropylene formulations offer improved stiffness in the 300,000 to 350,000 psi range, HDTs of 240 [degrees] F 250 [degrees] F to high flow rates, and low cost.

In addition to the company's compounded thermoplastic olefins (TPOs), Eastman is pursuing the possibility of reactor-produced TPOs to eliminate the compounding step, says Jim O'Neill, product specialist, polyolefins. Also, a number of filled and unfilled TPOs with up to 250,000 psi modulus are currently underdevelopment. Eastman is just commercializing resilient 40,000 psi and 80,000 psi compounded TPO formulations with low coefficients of thermal expansion, for air dams, fascias, license-plate brackets and interior trim.


Joseph Reed, general manager, automotive marketing, GE Plastics, says that the company's advanced instrument panel (AIM) and front-end module concepts are in vigorous development" with a number of OEMS, including transnationals. Prototypes have been built, and one effort is to simplify the manufacturing process. The front-end module, for example, would be an off-line assembled system that would include electrical wiring harnesses, heating, ventilating and air conditioning, and other functions built into an engineering polymer carrier. The unit would be pretested off-line and "dropped" into the car.

Reed predicts the concept of designing for resource recovery will get more attention and will involve strong interaction between OEMs and car dealers.


Himont Advanced Materials says that the new HiFax thermoplastic olefins, including the line of molded-in color materials used for fascias on selected GM vehicles, offer faster processing, improved color integrity, and better balance of stiffness and impact strength. Himont has also introduced a new family of HiGlass glass reinforced materials with high impact and melt flow properties. The resins, BJ-61A, 62A, 63A, and 64A, with 20%, 30%, 40%, and 50% glass, respectively, offer easy colorability and moldability, with low warpage and good surface finish.


Hoechst Celanese Engineering Plastics Division continues to develop its Riteflex BP line of thermoplastic elastomers (TPEs) for exterior applications such as bumper fascias. The company says that new grades with molded-in color and UV stability will reduce painting operations to a single-stop clear coat.

The stiffness and impact resistance of Celstran long fiber-reinforced resins have led to studies for possible use in structural parts, including bumper beams. Hoechst Celanese also plans to continue introduction of new impact grades of nylon. A UV-stabilized grade, available in colors with no significant loss in properties, was recently introduced.


Nicholas N. Ghoussaini, automotive business director, ICI Polyuethanes, says that the company's RIMline imine polyurea technology is currently active in OEM fascia and exterior body panel development programs. The bumper for the U.S. version of the Peugeot 405 is molded of an imine polyurea system. The easy-processing 13.5-lb part, based on MDI prepolymers and imino-functional polyethers, was the first full polyurea automotive component to go into production in 1990 in Europe.

ICI's RIMline system also is under development in a program with Toyoda Gosei USA to meet tight material formulation specs for Chrysler's driver side air bag doors. The material must perform over a broad temperature range and retain its elastomeric functions and break consistently even in extreme conditions.

Acoustiflex foam is used as a carpet underlay in the 1991 Lincoln Town Car and Continental. ICI products also are used in acoustical barriers for the 1991 GM Corvette, Caprice, and Saturn.

Ghoussaini says that ICI's all-MDI flexible foam is utilized for the 1991 Chrysler minivan poured-in-place seat, and that development programs are focused on other interior components.


Mobay Corp.'s automotive projects include a new concept car program with Ford; a nylon car seat with several U.S. car companies; use of a polycarbonate/ ABS blend for energy absorbing dampers; and cold molded polyurethane foam cushioning. The company also is participating in development of a modular concept door, now under test at an automotive manufacturer, that uses a polyurea outer panel with soft-feel coating and polyurethane encapsulation for the inner steel frame. Expected gains are reduced tooling costs, parts consolidation (because of the encapsulating ability of the RIM materials), and ease of assembly.

Mobay's Werner P. Witt, vice president and head of the company's Automotive Business Group, reports that impact testing is under way, with an automaker, of an all-polyuethane bumper consisting of a structural RIM beam, energy-absorbing polyurethane foam, and a RIM polyurethane fascia. All parts could be integrated into one ready-to-mount unit in which the foam encapsulates the reinforcing elements and also bonds to the fascia.


Monsanto Chemical Co. says use of high-heat resins in car interiors virtually tripled" in the 1980s because of interior heat buildup from the expanded use of glass. TPEs, as replacements for thermoset rubbers, are an active area. A new TPE to withstand continuous temperatures to 375 [degrees] C is in development.

New interior trim applications in the 1991 Chevrolet Caprice, Caprice Classic, and Jimmy Truck include conversion from polypropylene to Lustran Elite LGA SF. The Chevy J Cavalier uses glass-filled Cadon in its instrument panel retainer and Lustran Elite HH ABS in its low gloss, molded-in color console. The company also now can flock its Santoprene colorable TPE with polyester to meet adhesion and peel requirements for window seals, channels, and trims.
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Author:Wigotsky, Victor
Publication:Plastics Engineering
Date:Sep 1, 1990
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