国内外振动技术在塑料成型工艺中的应用

Application of Pulsing Technology to Plastics Molding at Home and abroad

介绍国内外振动技术在塑料成型工艺中的应用。通过振动保压、多点动态进料保压及推—拉注塑技术在注塑成型中的应用，有效地消除了制件中的缩孔、疏松和表面沉陷，控制了制件中增强纤维和分子链的取向，消除熔合痕，从而提高了产品质量。所述振动保压技术的基本工作机理是在保压过程中，使熔体产生剪切，得到内热，从而延缓了薄壁部位的冷却时间，使厚壁部分冷却收缩时能从浇口得到足够的熔料补充；其余两种技术是振动保压技术的进一步发展，它们能使熔融塑料受到更大的剪切，从而效果更好。上述技术成功的应用实例有：３ｍｍ厚的ＰＰ玻纤增强塑料采用多点动态进料保压成型，其熔接线强度提高了５０％～８５％；ＡＢＳ采用动态保压注塑成型，制品的拉伸强度提高了１７％；玻纤增强ＬＣＰ进行推—拉注塑，拉伸强度和弯曲模量分别提高了４２０％和２７％。

s The application of pulsing technology to plastics molding at home and abroad is described in this paper.Sinkhole,microvoid and surface sinking in molding could be eliminated by means of packing with pulsing,multiple live feed packing and push pull injection molding,making the orientation of the reinforcing fibers and macromolecular chains of the product under controlling,removing weld mark,resulting in improving the property of the product.The basic operation mechanism of packing with pulsing is to make melt to shear and produce internal heat during packing,delaying cooling time of thin walled section of the part,enabling thick walled section of the part to get enough melt for suplement from gate.The other two technologies are further developments of packing with pulsing technology,making melting plastics subjected to shear force and having better result.Successful applications of the above mentioned technologies are as follows∶when multiple live feed packing technology was applied to glass fiber reinforced PP(3mm by thickness),the welding strength increased by 50%～85%;and when to that of ABS,the tensile strength increased by 17%;when push pull injection molding technology was applied to glass fiber reinforced LCP,the tensile strength and bending modulus increased by 420%and 27% respectively.