1, Material characteristics
Polypropylene is widely used in front and rear bumpers of passenger cars because of its excellent cost performance. Since 1976, FIAT of Italy used the blend of copolymer of PP and E / P copolymer to make the world's first bumper. Since poly Propylene is widely used as a new, inexpensive, general-purpose plastic in the automotive field. At present, more than 80% of the bumpers in the world are made of TPO with polypropylene matrix.
2, Mold requirements
Mold to adapt to high beats, you need to have the following two conditions:
① Mold structure can not be too complicated, in the mold opening and closing process, the action simple and compact.
② Mold cooling effect is good, in about 10 seconds, the melt above 200 ℃ can be cooled to the surface of the state of 80-90 ℃. Requires good thermal conductivity of materials, mold design should also facilitate the layout of waterways. The company is located in:
Now bumper mold structure has two main structures, the internal and external type, the internal type is mainly used by European and American automobile manufacturers, its main feature is to ensure product quality, parting line design in the mold B surface, either Processing errors or molds produced after the long-term use of the flash will not affect the appearance of the product, the main lack of complex molds, usually 30-40 tons, the product cycle are generally more than 60 seconds, the Japanese car manufacturers usually use the outer sub-type structure. Parting line in front of the product, in order to ensure the appearance of quality, mold processing are put forward high requirements, but the mold structure is simple, the fastest cycle can reach below 40 seconds.