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Technical Paper

Prototype Design and Testing of a Thermoplastic Steering Wheel Armature

2007-04-16
2007-01-1218
Basic automotive steering wheel armature design has been largely unchanged for years. A cast aluminum or magnesium armature is typically used to provide stiffness and strength with an overmolded polyurethane giving shape and occupant protection. A prototype steering wheel armature made from a unique recyclable thermoplastic eliminates the casting while meeting the same stiffness, impact, and performance criteria needed for the automotive market. It also opens new avenues for styling differentiation and flexibility. Prototype parts, manufacturing, and testing results will be covered.
Technical Paper

Application of a MIC Metallic Flake ASA/PC Weatherable Resin Predictive Engineering Package

2006-04-03
2006-01-0135
The automotive industry continues to strive for mold-in-color (MIC) solutions that can provide metallic flake appearances. These MIC solutions can offer a substantial cost out opportunity while retaining a balance of weathering performance and physical properties. This paper discusses a predictive engineering package used to hide, minimize and eliminate flow lines. Material requirements and the methods used to evaluate flowline reduction and placement for visual inspection criteria are detailed. The Nissan Quest® luggage-rack covers are used to illustrate this application. The paper also explores how evolving predictive packages offer expanding possibilities.
Technical Paper

Inner Lens UV Vulnerablity Study

2004-03-08
2004-01-0800
To determine what effect (measured in haze), UV exposure has on polycarbonate inner lenses (coated and uncoated), when positioned behind qualifying (UV absorbent) and non-qualifying (UV transmitting) outer lens materials (clear and red). Plastic inner lenses are those covered by another material and are not exposed directly to sunlight.
Technical Paper

Design and Development of a Thermoplastic Structural IP

2003-03-03
2003-01-1388
An Instrument Panel (IP) cockpit is one of the most complex vehicle systems, not only because of the large number of components, but also because of the numerous design variations available. The OEM can realize maximum benefit when the IP cockpit is assembled as a module. This requires increased performance attributes including safety, durability, and thermal performance, while meeting styling and packaging constraints, and optimizing the program imperatives of mass and cost. The design concept discussed in this paper consists of two main injection molded parts that are vibration welded to form a stiff structure. The steering column is attached to the cowl and plastic structure by a separate steel column support. The plastic IP structure with integrated ducts is designed and developed to enable the IP cockpit to be a modular system while realizing the benefits of mass and cost reduction.
Technical Paper

Highly Predictive Accelerated Weathering of Engineering Thermoplastics

2003-03-03
2003-01-1192
Current accelerated weathering protocols such as SAE J1960 or ASTM G26 do not provide reliable, predictive results for engineering thermoplastics. Correlation factors among resin types and even different colors of a single resin have variations that are 60-100% of the mean at the 95% confidence level, making these tests useless for lifetime prediction or even reliable ranking of materials. We have developed improved conditions using CIRA/sodalime-filtered xenon arc, a more rain-like water spray, and occasional sponge-wiping of the samples. The data for gloss loss and color shift agree very well with Florida data giving a correlation factor of 3100±680 kJ/m2 (at 340 nm) per Florida year at the 95% confidence level. The acceleration factor is 7.6x.
Technical Paper

Evaluation of Aesthetic and Reflective Performance of Direct Metallized Resins for Automotive Lighting

2003-03-03
2003-01-0649
The aesthetic requirements for rear combination lamps have risen due to the increased use of optic free lens. The objective of this study was to develop a methodology to characterize the relative aesthetic performance for thermoplastic resins utilized for rear combination lamp housings. This study focuses upon the use of a direct metallization process. The results of this study will allow project engineers to better understand the relative performance of various materials.
Technical Paper

Predictive Weathering Tool for Color Formula Development

2003-03-03
2003-01-0798
A model has been developed and implemented at GE Plastics that predicts a material's color shift when weathered. The material's color shift is due to the summation of color shifts from each individual component. By individually measuring the change in each component's optical coefficients upon weathering and using a multiple light scattering model, one can predict the color shift of a material composed of mixtures of these components. The model has been shown to have a standard deviation of 0.4 to 0.9 when predicting color shifts E*, for PC-polyester copolymers, ABS, and ABS/PC blends using an automotive exterior test, SAE J1885, ASTM D 4674, and ASTM D 4459.
Technical Paper

Thermoformed Soft Instrument Panel

2003-03-03
2003-01-1171
The automotive industry is continually striving for opportunities to take additional cost and mass out of vehicle systems. Large parts such as an Instrument Panel retainer are good candidates because a small percent reduction in mass can translate into a significant material mass savings. Multiple requirements for a soft instrument panel including safety, stiffness, adhesion, etc. can make these savings difficult to achieve. This paper will describe how a new material and process development for the fabrication of a soft instrument panel can produce 50% weight savings with a 20% cost reduction potential. In addition, this new technology exhibits improved performance over existing materials during safety testing.
Technical Paper

Predicting the Bumper System Response of Engineering Thermoplastic Energy Absorbers with Steel Beams

2002-03-04
2002-01-1228
An efficient energy absorber (EA) will absorb impact energy through a combination of elastic and plastic deformation. However, the EA is typically coupled with a steel reinforcing beam, which can also elastically and plastically deform during an impact event. In order to design and optimize an EA/Beam system that will meet the specified vehicle impact requirements, the response of the entire assembly must be accurately predicted. This paper will describe a finite element procedure and material model that can be used to predict the impact response of a bumper system composed of an injection molded thermoplastic energy absorber attached to a steel beam. The first step in the process was to identify the critical material, geometric, and boundary condition parameters involved in the EA and Beam individually. Next, the two models were combined to create the system model. Actual test results for 8km/hr.
Technical Paper

Managing Thermal Growth for Large Class “A” Polymer Body Panel Closure Systems

2002-03-04
2002-01-0276
The history behind Polymer Class “A” Body Panels for automotive applications is very interesting. The driving factors behind these applications have not changed significantly over the past sixty years. Foremost among these factors is the need for corrosion and dent resistance. Beginning with Saturn in 1990, interest in polymer body panels grew and continues to grow up to the present day, with every new global application. Today, consumers and economic factors drive the industry trend towards plastic body panels. These include increased customization and fuel economy on the consumer side. Economic factors such as lower unit build quantities, reduced vehicle mass, investment cost, and tooling lead times influence material choice for industry. The highest possible performance, and fuel economy, at the lowest price have always been a goal.
Technical Paper

Two-Shot and Overmolding Technology for Automotive Applications Using Engineering Thermoplastics

2002-03-04
2002-01-0274
There are a multitude of opportunities to utilize two-shot or overmolding technology in the automotive industry. Two-shot or overmolding a thermoplastic elastomer onto a rigid substrate can produce visually appealing, high quality parts. In addition, use of this technology can offer the molder significant reductions in labor and floor space consumption as well as a reduction in system cost. Traditionally, two-shot applications were limited to olefinbased TPE's and substrates, which often restricted rigidity, structure and gloss levels. With the development of thermoplastic elastomers that bond to engineering thermoplastics, two-shot molding can now produce parts that require higher heat, higher gloss and greater structural rigidity. This paper will outline engineering thermoplastics that bond with these new elastomers, discuss potential applications, and review circumstances that offer the best opportunity to call upon the advantages of two-shot and overmolding technology.
Technical Paper

Conductive Plastics Leading Fuel Door Technology

2002-03-04
2002-01-0278
This paper will discuss, compare, and contrast current materials, designs, and manufacturing options for fuel filler doors. Also, it will explore the advantages of using conductive thermoplastic substrates over other materials that are commonly used in the fuel filler door market today. At the outset, the paper will discuss the differences between traditional steel fuel filler doors, which use an on-line painting process, and fuel filler doors that use a conductive thermoplastic substrate and require an in-line or off-line painting process. After reviewing the process, this paper will discuss material options and current technology. Here, we will highlight key drivers to thermoplastics acceptance, and look at the cost saving opportunities presented by the inline paint process option using a conductive thermoplastic resin, as well as benefits gained in quality control, component storage and coordination.
Technical Paper

Conductive Polyphenylene Ether/Polyamide Blend for Saturn Exterior Body Panels

2001-03-05
2001-01-0446
The evolution toward the use of electrostatic painting processes has been driven primarily by environmental legislation and efforts to improve efficiencies in the painting process. The development of conductive substrate material compliments the industry trend toward a green environment through further reductions in emissions of volatile organic compounds during the painting process. Traditionally, electrostatic painting of thermoplastics requires that a conductive primer be applied to the substrate prior to topcoat application. The conductive polymer blend of polyphenylene ether and polyamide provides sufficient conductivity to eliminate usage of conductive primers. Additional benefits include improved transfer efficiencies of the primer and top coat systems, uniform film builds across the part, and improved painting of complex geometries.
Technical Paper

Predicting Impact Performance of Painted Thermoplastic Exterior Body Panels

2001-03-05
2001-01-0445
Automotive exterior paint systems can significantly affect the impact performance of thermoplastic body panels. To utilize the benefits of predictive engineering as a tool to assist in the design and development of thermoplastic body panels, thermoplastic body panel materials have been characterized with typical automotive paint systems for use for finite element modeling and analysis. Paint systems used for exterior body panels can vary from rigid to more flexible, depending on the vehicle manufacturer's specifications. Likewise, thermoplastics for body panels vary in mechanical properties, primarily depending on the heat performance requirements of the application. To understand the effects of paint systems on impact performance of thermoplastic body panels, two different paint systems, representing “rigid” and “more flexible,” were evaluated on two body panel grades of thermoplastics with different mechanical properties.
Technical Paper

Thinwall Injection Molding for Instrument Panels

2001-03-05
2001-01-1272
As the global auto industry wrote the final chapter on its first century, we saw the average thickness of an automotive instrument panel drop from 3.0 mm-3.5 mm to 2.0 mm-2.3 mm, as found in the 1999 Volkswagen Jetta and Golf. By reducing the wall thickness of the instrument panel, Volkswagen started an industry trend: both OEMs and tiers are investigating technologies to produce parts that combine a lower cost-per-part via material optimization and cycle-time reduction with the superior performance of engineering thermoplastics. The goal is to produce parts that are positioned more competitively at every stage of the development cycle - from design, to manufacturing, to assembly, to “curb appeal” on the showroom floor. The key to this manufacturing and design “sweet spot” is a technology called thinwall - the molding of plastic parts from engineering thermoplastics with wall thicknesses thinner than conventional parts of similar geometry.
Technical Paper

Lightweight Thermoplastic Composite Throttle Bodies for Car and Truck Applications

2001-03-05
2001-01-1140
The drive to reduce weight, simplify assembly, and cut total system cost in today's vehicles is relentless. Replacing metal systems with thermoplastics has been of considerable interest in the engineering community. The current generations of engineering thermoplastic resins are enabling the use of plastic systems in demanding underhood applications. Technical data and discussion regarding the materials, design, molding, and assembly of lightweight composite throttle bodies will be presented in this paper. Comparisons with machined aluminum throttle housings are drawn to establish a baseline with the throttle body housing component that is most common in production today. Design flexibility and process simplification are some of the approaches highlighted. Much of the technical information provided in the paper applies to both cable driven mechanical throttle bodies as well as electronic throttle bodies under development.
Technical Paper

USCAR/EWCAP Requirements & Materials to Meet the Challenge

2000-03-06
2000-01-0042
Traditionally, the automotive electrical industry has used thermoplastic polyesters, nylon, and nylon alloys for its primary plastic applications. Current materials-specification trends in this segment are being dictated by 10-year warranty requirements (USCAR's EWCAP tests), higher functionality, increased pin densification, and elevated operating temperatures. This paper will discuss the implications of these trends and discuss materials approaches needed to address both application and manufacturing challenges.
Technical Paper

Development of the Xterra® Luggage-rack System from Nissan with ASA/PC Weatherable Resin

2000-03-06
2000-01-1068
The luggage-rack-system market has historically been dominated by nylon- (polyamide)-based resins. The recent design and development of the Xterra® luggagerack system (LRS) from Nissan represents a new trend in luggage-rack system design. Nissan utilized an ASA/PC weatherable thermoplastic resin to develop its special gray, molded-in-color luggage-rack components. The balance of weathering performance and physical properties that ASA/PC resin offers allowed the automaker to design these structural components and avoid the high cost of paint. This paper discusses the design and development of the luggage-rack system as well as the process utilized to evaluate ASA/PC resin for performance in static loading, heat resistance, vibration performance, etc. Furthermore, the paper explores how ASA/PC resin parts might be designed in for future luggage-rack-system applications.
Technical Paper

Material Characterization and FEA Correlation for Engineering Thermoplastics Under High Strain Loading

1999-09-28
1999-01-3175
As a result of the increased reliance on predictive engineering to reduce vehicle development resources, increasingly accurate predictive finite element models are important to help engineers meet cost and timing restrictions. For components made of engineering thermoplastics, accurate material modeling that helps predict part performance is essential. This material modeling accuracy is even more important where high speed and high loading conditions exist such as in airbag doors, knee bolsters and pillar trim. This paper addresses material modeling of engineering thermoplastics for finite element models that are subjected to high impact and high speed loading. Here, the basics of plastics behavior are introduced and a comparison of the accuracy of different material characterizations in an impact loading is presented. The material under analysis here is a polycarbonate - acrylonitrile butadiene styrene blend, PC-ABS.
Technical Paper

Using Polyetherimide Thermoplastic for Forward Lighting Complex Reflectors

1999-09-28
1999-01-3179
This paper will discuss the analysis of a high-heat, unfilled polyetherimide (PEI) thermoplastic in a complex reflector application with conventional aim (bubble-vial) beam pattern. The advantages and disadvantages of using PEI thermoplastic vs. bulk molding compound (BMC) in a complex reflector will be presented. Design features, testing methodology, and processing techniques for the use of PEI in such applications will also be highlighted.
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