Plastic materials for automobile headlights Headlights are an indispensable component of automobiles, which are related to lighting, signaling and decoration of automobiles. After years of development, degree of plasticization of headlight production has reached more than 96%. Main components of automobile headlights are composed of reflectors, lenses, shells, light sources, electronic circuits, and installation accessories. At present, main plastic materials used in automobile headlights in my country are PC, PP, ABS, PC/ABS, PMMA, PBT, PET, PA, BMC and a few other plastic materials. Plastics have advantages of light weight, corrosion resistance, good impact resistance, high transparency, good insulation, low thermal conductivity, good mechanical properties, strong plasticity, and molding processing. They are increasingly widely used in various fields.
Tag: engineering plastics
So-called engineering plastics are industrial plastics that can replace metals and be used as industrial parts or shell materials. Engineering plastics need to have excellent comprehensive performance. Compared with generalĀ plastics, they can meet higher requirements in mechanical properties, heat resistance, durability, corrosion resistance, etc. In addition, they are easier to process and can replace metal materials.
Engineering plastics can be used as engineering materials and plastics that replace metal in manufacturing machine parts. Engineering plastics have excellent comprehensive properties, such as high rigidity, low creep, high mechanical strength, good heat resistance, and good electrical insulation. They can be used for a long time in harsh chemical and physical environments. They can replace metals as engineering structural materials, but they are more expensive and have smaller output.
On the basis of general plastics and engineering plastics, through physical, chemical, mechanical and other methods, through filling, blending, reinforcement and other processing methods, performance of plastics is improved or functions are added, mechanical properties such as flame retardancy, strength, impact resistance, toughness of plastics are improved and enhanced,Ā making plastics suitable for use in special electrical, magnetic, light, thermal and other environmental conditions.
Full name of LCP plastic raw material is LIQUID CRYSTAL POLYMER.Ā It is a new type of polymer material that generally exhibits liquid crystallinity in molten state. These materials have excellent heat resistance and molding processability. Polymerization method is mainly based on melt polycondensation, and solid phase polycondensation is often supplemented by fully aromatic LCP to obtain high molecular weight products.
Plastic is a polymer organic material with resin as its main component, which can be molded into a certain shape under a certain temperature and pressure, and can maintain a certain shape at room temperature. Resin refers to an organic polymer that usually has a transformation or melting range when heated. It is fluid under action of external force during transformation and is solid, semi-solid or liquid at room temperature. It is the most basic and important component of plastics. Broadly speaking, any polymer that is basic material of plastics in plastics industry can be called a resin.
Engineering plastics - refers to a class of high-performance polymer materials that can be used as structural materials to withstand mechanical stress in a wide temperature range,Ā used in harsh chemical and physical environments.
Scanner base products are shown in Figure 1. Maximum dimensions of product are 371.37 mm *Ā 285.93 mm *Ā 65.83 mm; average thickness of plastic part is 2.50 mm, material of plastic part is PS HI, shrinkage rate is 1.005, and weight of plastic part is 391.30 grams. Technical requirements for plastic parts are that there should be no defects such as peaking, underfilled injection molding, flow lines, pores, warping deformation, silver streaks, cold material, and jetting lines, and meet ROSH environmental protection requirements.
Foreign engineering plastics industry started earlier. In 1931, DuPont Company of United States synthesized PA66 for the first time in laboratory. In 1939, PA66 realized industrialization and was the first industrialized engineering plastic. From 1950 to 1980, it was a period of rapid development of global engineering plastics industry. Bayer of Germany, DuPont of United States, and Qiqi of United States successively developed engineering plastics such as polycarbonate (PC), polyoxymethylene (POM), and polyimide (PI).
Compression injection molding is a more traditional injection molding method Principle: First inject molten material into mold cavity, when molten material enters mold lung. Mold is opened a little under its pressure knife; after molten material fills cavity, mold is locked with high pressure to obtain desired product. Second step is compression molding. Since molten material enters cavity when mold has been slightly opened, required mold force is relatively small. When molding, screw no longer injects material into mold cavity, but mold is locked by high pressure so that force Lf is pressed against plastic to form, so orientation of product is small and internal stress is low. This method is especially suitable for products with small volume and high transparency requirements;
Gud Mould 