Automotive Headlamps

The large volume applieations for moisture-euring polyurethanes are diseussed briefly in the applieations seetion below. These adhesive offer superior low temperature, high temperature, and speeifie adhesion performanee in comparison to conventional hot melts. These attributes have allowed them to excel in various product assembly applications, including structures such as windows, doors, furniture, and automotive headlamps and trim. Newer applications include bookbinding, fabric laminating, and assembly of athletic shoes. 

High appearance polyester automotive headlamp housings. 

Automotive headlamp manufacturers usually heat-fuse glass to join lenses to reflectors and to seal assembly holes. Heat-curing epoxy adhesives provide some energy savings over the fusion process but still require long heating times and substantial capital investment. 

In applications requiring higher thermal performance, a polyester-carbonate copolymer has been developed with an HDT that is 28°C (50°F) higher than that of standard polycarbonate homopolymers (see the section Polyestercarbonates and Other High-Heat Polycarbonates ). The most common use of this material occurs in automotive headlamp applications, where the copolymer forms the metallized reflector, and in animal cages that require repeated autoclave sterilization. 

For applications where polycarbonate homopolymers or copolymers lack sufficient thermal performance, blends with polyetherimide (PEI) are often used. PEI, which also contributes excellent flammability and low smoke generation to the alloy, may be combined with either straight polycarbonate or polycarbonate blends, depending on what other properties are required. The most common uses are found in light reflectors for automotive headlamps, components for aircraft interiors (especially wall and ceiling panels), and food-contact applications for microwave-to-table cookware. 

Figure 95 Automotive headlamp assembly, new BMW Limousine 5 series, produced at Hella KG Hueck Co.

A typical application in nylon is automotive headlamp housings where dimensional control is critical. Substantial quantities of mica are also used in thermoplastic polyesters. 

Polycarbonate was invented in 1953 in the United States at GE Plastics and at about the same time in Germany at Bayer. GE marketed the polymer as Lexan and Bayer as Makrolon . In 2007, GE sold its plastics business to SABIC (Saudi Basic Industries Corporation), but the Lexan name is still used. About 30 years after the original invention, Dow Chemical Co. began offering polycarbonate under the name Cahbre . Polycarbonate is an amorphous polymer and has excellent clarity, dimensional stability, and toughness. It is used for bullet-resistant windows and automotive headlamps. 

There are also advantages with glass fibre-reinforced materials. For example, the typical processing temperature with 30% glass fibre-reinforced PEI (360-380 °C) blended with 21% PPO can be reduced to 310-340 °C. This flow-optimised technology can find applications in, for example, automotive headlamp reflectors, lamp bases, throttles, chip carriers and aerials. 

Automotive appHcations account for about 116,000 t of woddwide consumption aimuaHy, with appHcations for various components including headlamp assembHes, interior instmment panels, bumpers, etc. Many automotive appHcations use blends of polycarbonate with acrylonitrile—butadiene—styrene (ABS) or with poly(butylene terephthalate) (PBT) (see Acrylonitrile polymers). Both large and smaH appHances also account for large markets for polycarbonate. Consumption is about 54,000 t aimuaHy. Polycarbonate is attractive to use in light appHances, including houseware items and power tools, because of its heat resistance and good electrical properties, combined with superior impact resistance. 

Injection Molding Electrical connector housings Light bulb sockets Flashlight housings Car headlamp bodies Circuit breaker boxes Headlight reflectors Automotive body components Computer keys Iron housings... 

Figure 14.19 Typical automotive applications made from glass-filled recycled PET compounds (a) heating and air conditioning door duct vents for Ford s Taurus, Mercury Sable and Lincoln Continental models (b) engine covers for Ford vehicles (c) fixed window surround for the Ford Excursion model (d) headlamp retainer for GM s Montana, Yukon and Sierra trucks...

Brief details are given of the use of LDPE and EVA foams in automotive and leisure applications. Examples mentioned are car boot mats and interior mats, vehicle trim, headlamp gaskets, and vibration absorbers, gym mats, luggage, boat hull cladding, sports wear and buoyancy aids. 

Automotive accessories (hatchback door closers, hydraulic shock absorbers, headlamp lenses, trim pieces, etc.)... 

Automotive applications In the automotive industry, special primers for composite body panels, Class A paints, accessories, headlamps and solid... 

Application areas for the new Co-PCs include electrical engineering/elec-tronics, domestic appliances, lighting, automotive engineering, and medical technology. In automotive engineering the headlamp lens will be offered by headlamp manufacturers as the plastics alternative to main headlamps and fog lamps. The best compromise on optical data, mechanical strength, and heat deflection resistance for their application is shown by PC. 

Thermoplastic alloys based on styrene maleimide with PA have good thermal stabUity, chemical resistance, abrasion resistance, paintability and weatherability. Those blended with ABS combine thermal resistance with very good processabUity. The alloys find use in various automotive components such as defroster grills, door handles, and headlamp surrounds. 

Applications and uses telephone line splice cases, switches, connectors, housings, improved impact brake and fuel line clips, wheel covers, headlamp bezels and covers, panels, power distribution boxes, cold temperature air bag doors, automotive safety systems, wheel covers, impact fascias, improved impact appliance lids, power tools, panels, and housings. 

Polyarylates are used in automotive applications such as door handles, brackets, and headlamp and mirror housings. Polyarylates are also used in electrical applications for connectors and fuses. The polymer can be used in circuit board applications, because its high temperature resistance allows the part to survive exposure to the temperatures generated during soldering. The excellent UV resistance of these polymers allows them to be used as a coating for other thermoplastics for improved UV resistance of the part. The good heat resistance of polyarylates allows them to be used in applications such as fire helmets and shields. ... 

Product complexity is characterized by factors such as increasing of functions and components, but also component complexity, when a component integrates more functions and subcomponents. For instance, the number of electric components has increased in cars and therefore, the total length of the electric cables used in today s generation of well-known cars has reached a multiple of their initial values. Furthermore, components such as headlamps have been improved to include more functions, but also more sub-components such as sensors which are connected with the CAN-bus. These very small examples can give a brief impression of the real challenge that is to be tackled in product development nowadays and in particular, in the automotive industry. 

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