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The magnesium alloy AE42 (nominally a 4 % aluminum, 2 % rare earth alloy of magnesium) is a developmental die cast alloy with good strength and creep resistance at elevated temperatures. Standard salt spray corrosion tests have been used with controlled purity AE42 die castings to define the critical iron, nickel and copper contaminant levels below which excellent corrosion performance can be obtained. As previously observed with the magnesium alloys AZ91, AM60, and AS41, the critical iron content is dependent upon the manganese content of the alloy. While the iron:manganese tolerance for AE42 is about the same as that of AM60, the tolerance for the nickel and copper contaminants is greater than that of AZ91. When each of these contaminants is less than the critical level, the salt spray performance was equal to or better than die cast 380 aluminum and cold rolled steel.

Continued development of Reinforced Reaction Injection Molding (RRIM) polyurea polymers for toughness, blister resistance and large-part processing as exterior vertical body panels has launched ELPO-compatible exterior outers into automotive assembly-line operations. This allows automotive OEM design to take advantage of the unique molding shapes for side outers and fenders while reducing weight, assembly (DFA) and time/operations costs (DFM). Polyurea RRIM body panels have been successful in meeting the demanding auto industry requirement for lightweight, damage-resistant exterior outer panels as an economical alternative to steel. Design freedom advantages, low prototype cost and tooling savings through predictive modelling have allowed the commercial use of RRIM body panels. This high-temperature-resistant polyurea RRIM composite allows on-line painting, including passing through the steel corrosion protection primer (E-coat) cure environments.

The American public's desire to recycle and the predictions of future recycle mandates are motivating automotive OEMs and plastic suppliers to address the recycling of plastic materials. As a result, the OEMs and plastic industry groups have asked resin suppliers, automotive dismantlers and reprocessors to assist them in studying and developing solutions for the recovery of post-consumer automotive plastics and recycling those materials back into automotive applications. The Dow Chemical Company has been a participant in plastic industry sponsored projects and has initiated numerous research and development activities involving the recycling of automotive thermoplastic and thermoset materials, as well.

The use of low density reinforced Reaction Injection Molded (RIM) substrates for covered interior automotive articles continues to increase globally. Reduced party mass, consolidation of manufacturing steps (labor), and the use of aluminum tooling, instead of steel, are cited advantages that LD-RIM offers when compared to traditional wood based and thermoplastic materials. Two RIM processes are successfully being used to produce covered interior door panels. Low density structural RIM (LD-SRIM), utilizing conventional RIM equipment, involves the placement of a pre-cut fiberglass mat in the tool cavity prior to open-pour injection of the 2-stream liquid urethane components. Low density reinforced RIM (LD-RRIM), utilizing lance cylinder RIM equipment, incorporates reinforcing fibers, such as milled fiberglass or wollastonite, in the liquid resin component. The liquid resin containing reinforcing filler is injected with the isocyanate component into a closed mold.

A fully-integrated thermoplastic structural instrument panel (IP) system will be implemented on Chrysler's Dodge Dakota Truck Platform. The structural IP consists of a three-piece monocoque thermoplastic injection molded structure that replaces the traditional retainer, air delivery ducts, steel beams and reinforcements typically used in IP designs. Ribbed thermoplastic bolster systems have been incorporated as part of the energy management system. The structural IP provides the required stiffness to satisfy noise, vibration, and harshness (NVH) quality targets and the necessary strength and rigidity to effectively meet FMVSS No. 208 requirements for managing occupant and passenger air bag (PAB) deployment loading during 48 km/h (30 mph) frontal crashes.

The recycling of plastics from end of useful life durable goods continues to evolve as an issue. Recycle strategies need to be based on a careful understanding of sustainability for both the environmental and business domains. The definitions and processes utilized in a recycle program can dramatically affect the economic structure. These recycle programs need to be carefully constructed to minimize cash costs. There is an emerging industry, recyclers, who may become an important link in the recycle supply chain.

The increase in instrument panel design and functional performance requirements has resulted in a variety of structural architectures that have been utilized in different passenger vehicles, vans, and light trucks. Each architecture can be designed and engineered to meet corporate and federal requirements using different levels of integration, functionality consolidation, and assembly simplification. The present paper reviews three basic IP design architectures, i.e., traditional, hybrid, and structural, and discusses the performance requirement-functionality matrix in each case. Emphasis is given at explaining the role components play in the different architectures, defining their contribution to static, dynamic and crash performance and their relation to the overall assembly process and sequence. Performance and functionality requirements are linked to basic material characteristics that guide material selection for achieving design targets.

Cushioning and load distribution performance of plastic foams was investigated, using a human faceform as the loading object. A technique for measuring contact surface between faceform and plastic foam was developed. Transferrable paint applied to the foam facilitated determination of average stress over its surface, which in turn was employed to evaluate load distribution properties of the foam. Impact and static testing results on several plastic foams were analyzed. It was found that a good cushioning material characterized by low peak deceleration might show high average stress, thus making it an inefficient load distributor. The faceform used in the study incorporates the effect of face geometry during loading and thus provides a realistic simulation. Variation of material response with loading geometry and possible correlation between load distributing properties and rigidity of the foam are also discussed.

Standard salt spray corrosion tests have been used with controlled purity AM60 castings to define the critical iron, nickel, and copper contaminant levels below which excellent corrosion performance can be obtained. As previously observed with the AZ91 alloy, the iron solubility and the corrosion tolerance limit for iron are dependent upon the manganese content of the metal. The zinc free AM60 alloy has a somewhat lower tolerance for all three of the critical contaminants when compared to AZ91, but when the three contaminants are below their individual tolerance limits, the salt spray performance is again equal to or better than die cast 380 aluminum and cold rolled steel.

In 1998, approximately 57,000 Tonnes of plastic composites were utilized as body panels on cars and trucks in North America. Three material types, generically labeled SMC, RIM and Thermoplastic are vying to carve a market niche from steel which dominates the market place with an estimated volume of 1 million Tonnes per year. Since plastic body panels have higher material costs but lower tooling costs, they are primarily utilized when build volumes are less than 200,000 vehicles per year or specific composite performance capabilities are demanded. This paper reviews the various performance parameters required of a body panel material and the relative strengths of Aluminum, RIM, SMC, Steel and Thermoplastics to meet these demands. A decision making process is utilized which allows for a comparison between the different materials. Since cost is so critical, it is left as an independent variable.