POM GR-20宝理--销售部联系人-蒋先生 手机: 公司座机:0769-89977070
POM GR-20宝理--Because POM is a crystalline polymer, its meltoften changes with a larger volume when it is cooled. In theextrusion process, when the melted strip enters the cooling tank,the surface will solidify into a surface cortex instantaneously,while the core part is still in a melting state. As the striphardens gradually from outside to inside, the volume decreases. Theresulting shrinkage force acts on the resin that has not yethardened in the core, which is equivalent to an equal tensile forceon the core. As a result, continuous shrinkage holes are formedalong the length of the core of the strip. In the process ofextrusion, the water temperature in the cooling tank should becontrolled, and the water temperature should be increased as far aspossible under the premise of operation. The injection pressure ofPOM is high and the process length is longer. In order to ensurethe filling of parts, relatively high injection pressure is needed.The larger the holding pressure, the higher the dimensionalaccuracy of POM parts. POM has large crystallinity and narrowmelting range. When it is cooled and hardened, it often produces alarge volume shrinkage of 2.8%. In order to make up for the sizedefect, it is necessary to have sufficient holding pressure.Therefore, in injection moulding of POM, increasing the holdingpressure properly can reduce and eliminate the phenomenon ofwarping, shrinkage pits and internal holes in POM products.
韩国工程塑料POM是综合性能较好的工程塑料，但为了改善其耐热性、刚性、尺寸稳定性、耐疲劳性、耐蠕变性和力学性能，往往对聚甲醛进行复合增强，以满足各种特殊用途的使用。聚甲醛复合增强中所使用的填料，主要有长短玻璃纤维、碳纤维、玻璃微珠、滑石粉或钛酸钾晶须等。Hoechst公司的长纤维增强POM的落标冲击强度为普通纤维增强聚甲醛的8倍，它推出的两种25%玻璃纤维增强聚甲醛，强度Zui高，其拉伸强度高达128MPa，并具有优良的热性能，低摩擦性、耐磨性、抗蠕变性和耐低温性，常可用于制造性能要求严格的零部件，如燃油系统零件、车窗升降摇柄、安全控制部件及泵叶轮、泵壳等
销售部联系人-蒋先生 手机: 公司座机:0769-89977070
