汽车把手件气辅成型气指缺陷影响因素分析

Influence Factor Analysis of Gas Fingering Defect in Gas-assisted Injection Molding of Automobile Handle

在气体辅助成型工艺中,常常遇到一种缺陷是'气指',气泡穿过气道形成指状分支,严重的'气指'会降低注塑件的强度,造成气辅成型技术的失败,或者不能发挥气辅成型技术的优势。为了消除或减少这种缺陷的产生,本文采用数值模拟方法和正交试验方法对气辅成型制品'气指'缺陷进行了研究。研究了对'气指'缺陷影响最重要的6个工艺参数:熔体短射量、气体注射延迟时间、气体注射压力、模具温度、熔体温度以及气体注射时间对气辅成型制品'气指'缺陷的影响关系。结果表明,影响'气指'最重要的工艺参数依次是气体注射延迟时间、熔体温度和气体注射压力。因此优先选择合理的延时,熔体温度和注气压力参数尤为重要,为控制气指行为建议在相同熔体温度下适当延长气体注射延迟时间。

A frequent problem encountered in gas-assisted injection molding（GAIM） is gas fingering, i.e. gas bubbles penetrating outside designed gas channels and forming finger-shaped branches. Severe gas fingering will result in reduction of part strength, failure of gas-assisted injection molding or cancellation of the advantages of GAIM. Gas fingering defects in GAIM parts are investigated with the methods of numerical simulation and orthogonal experiment. Six process parameters that have the most important influence on gas fingering defect are studied, i.e. shot size, gas delay time, gas injection pressure, mold temperature, melt temperature and gas injection time. The results show that the most important process parameters that influence gas fingering are gas delay time, melt temperature and gas injection pressure successively. Therefore, to choose reasonable gas delay time, melt temperature and gas injection pressure is particularly important. For reducing the degree of gas fingering, it is suggested that at the same melt temperature the gas delay time should be appropriately prolonged.