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Over the last decade, on small- and medium-size passenger cars, a new class of front bumper - injection or blow molded from engineering thermoplastics - has been put into production use. These bumper systems provide full 8-km/hr federal pendulum and flat-barrier impact protection, as well as angled barrier protection. Thermoplastic bumpers, offering weight, cost, and manufacturing advantages over conventional steel bumper systems, also provide high surface finish and styling enhancements. However, there remain questions about the durability and engineering applicability of thermoplastic bumper systems to heavier vehicles. This paper presents results of a preliminary study that examines the durability of thermoplastic bumpers drawn from production lots for much lighter compact, and mid-size passenger cars against baseline steel bumper systems currently used on full-size pickup truck and sport-utility vehicles (SUVs). Bumpers were subjected to U.S.

The formulation of injection moldable thermoplastics with small loadings of graphite nanotubes provides sufficient conductivity in molded parts to allow for use in electrostatic painting applications. Normally, plastic parts need to be painted with a conductive primer prior to the electrostatic painting of base and clear coats. The use of conductive plastics eliminates the need for the priming step, and improves paint transfer efficiency and first pass yield. These elements provide obvious savings in materials and labor. What is less obvious, however, is the dramatic positive environmental impact that can occur through the reduction in emissions of volatile organic compounds (VOCs). Graphite nanotube technology provides advantages over other technologies such as conductive carbon black. In order to reach the percolation threshold for conductivity in carbon-black-containing resins, the loading of carbon black required tends to embrittle the polymer.

Electrostatic painting of exterior body components is considered standard practice in the automotive industry. The trend toward the use of electrostatic painting processes has been driven primarily because of environmental legislation and material system cost reduction efforts. When electrostatically painting thermoplastic body panels, side by side with sheet metal parts, it is imperative that the thermoplastic parts paint like steel. Electrostatic painting of thermoplastics has traditionally required the use of a conductive primer, prior to basecoat and clearcoat application. The use of conductive plastics eliminates the need for this priming step, while improving paint transfer efficiency and first pass yield. These elements provide an obvious savings in material and labor. The most significant benefit, is the positive environmental impact that occurs through the reduction in the emission of volatile organic compounds (VOC's).

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.

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.

Engineering thermoplastics are being used increasingly in automotive exterior body applications; most of these applications require that the panels be painted “on line” with the rest of the car body at relatively high temperatures. The high temperatures associated with the painting/conditioning of the car have been shown to cause dimensional stability problems on automotive fenders molded from NORYL GTX®. This paper contains the results of an extensive FEA investigation targeted at determining what factors cause dimensional problems in fenders exposed to high heat. The ABAQUS FEA software was used to perform computer simulations of the process and the C-PACK/W software was used to determine molded in stress values.

Traditional knee bolster designs consist of a first-surface plastic component covered by paint or vinyl skin and foam, with a subsurface steel plate that transfers knee loads to 2 steel crush brackets. The design was developed to meet FMVSS 208 and OEM requirements. More recently, technological developments have allowed for the steel plate to be replaced by a ribbed plastic structure, which offers cost and weight savings to the instrument panel system. However, it is still a hybrid system that combines plastic with the 2 steel crush brackets. This paper will detail the development of an all-plastic design, which consolidates the plastic ribbed reinforcement plate with the 2 steel crush cans in a single engineering thermoplastic component. The new system is expected to offer further cost and weight savings.

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.

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.