注射成型工艺参数对聚丙烯制品翘曲的影响及机理研究

Effect of Injection Molding Parameters on Warpage of Polypropylene Product and Its Causation

使用正交实验法分析聚丙烯(PP)塑料熔体温度、模具温度、注射和保压压力及注射速度四个工艺参数对制品翘曲度的影响。讨论了这四个工艺参数对结晶度的影响并解释其对翘曲度的影响机理。研究表明,增大压力会使制品分子间距降低,材料不易结晶,翘曲度减小,其影响能力也最大;模具温度会影响熔体在最大结晶速度温度下的停留时间,对翘曲度的影响较明显;注射速度通过影响熔体分子的排列和晶型来影响结晶度,其对翘曲度的影响也较明显;熔体温度在注射成型过程中会有较大变化,故对结晶度和翘曲度影响最小。

The effect of process parameters like melt and mould temperatures, injection and holding pressures, and rate of injection on the warpage of PP parts were investigated through orthogonal experiments. The degree of warpage could be explained by crystallinity. High pressure inhibited crystallization and thus depressed the warpage. The higher the mold temperature, the longer the time of crystallization. Higher injection rate may cause higher degree of orientation. Both factors promoted the warpage. Melt temperature possessed less influence on the warpage.