mk4 golf r line mkv r32 rear bumper for sale

PP/Glass Fiber

It is of great significance for bumper manufacturing materials to continue to deepen the research on the modification of PP materials. Different effects can be achieved through the modification of different systems, such as glass fiber reinforced PP (pp/glass fiber), which can not only effectively reduce the weight, but also increase the strength and hardness of the material. Glass fiber reinforced polypropylene (GRP) has excellent performance price ratio, which keeps the low cost of PP. In the glass fiber reinforced thermoplastic, its density is the smallest, so it also has an advantage in weight.

The glass fiber has no effect on the static crystalline morphology of polypropylene. The spherulites of polypropylene pass through the glass fiber without forming a transition crystal at the interface. In the process of fiber drawing, there will be obvious transition crystal (transcrystalline) at the interface between polypropylene and glass fiber. This is because under the tensile action, the interface produces stress, which promotes the formation of transition crystal forms. Adding maleic anhydride in the blending process, the grafting of maleic anhydride will significantly reduce the spherulite size of polypropylene and increase the firmness of blending. Glass fiber reinforced polypropylene has large fluidity, wide range of forming conditions, good water resistance, chemical corrosion resistance and good mechanical properties. It is very suitable to be used as the manufacturing material of bumper.

PC/PBT

PBT has fast crystallization speed and is suitable for high-speed forming parts. It has high strength and excellent heat resistance, and can work in an environment higher than 100 ℃ for a long time. It has low water absorption, small linear expansion coefficient, excellent bending creep resistance, good dimensional stability, not easy to burn under high temperature, excellent electrical performance, hardly affected by humidity and temperature, excellent chemical resistance, good processing performance, short forming cycle, and is suitable for parts with complex shape or thin wall thickness. Pc/pbt alloy has high mechanical properties, and its impact strength is much higher than that of PP bumper. Xenoy series pc/pbt alloy produced by GE company in the United States can not only withstand collision, but also can withstand 155 ℃ /30 min baking and drying when the car body and bumper are coated (so that the bumper and car body remain the same color). BASF's ultrablend series pbt/pc alloy not only has the chemical resistance, oil resistance and fluidity of PBT, but also has the low-temperature toughness, heat resistance and high mechanical properties of PC. It is very suitable for the production and manufacture of bumpers.

Appearance quality

The appearance quality requirements of automobile bumper products can be selected according to the product scope of application, model level and customer requirements. The main contents include:

• The color, texture and gloss of bumper product surface shall be uniform without obvious difference.

• The visible surface of the product shall be free from cracks, flash, bubbles, flow marks, shrinkage cavities, depressions, pollution and other defects that may damage the appearance and performance.

• Gate, ejector rod position and parting surface are generally not allowed to be set on the appearance surface of part identification grade "a", unless they are approved by the OEM product engineer before the mold design scheme is finalized.

• The decorative surface of the painted product shall be free of obvious shrinkage marks, flow marks, welding marks, shrinkage cavities, scratches and other defects affecting the appearance.

• The skin texture area starts from 0.5mm of the parting surface, and the skin texture is allowed to be eroded within 1.0mm of the lower edge of the part.

Gloss

Gloss requirements will play a key role in the appearance quality of automobile bumpers. The type of gloss, incident angle, mirror gloss and other technical parameters shall be specified. For example, the gloss of the outer surface of the bumper is (60 °) 4.1, which conforms to the standard gloss template.

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