注气工艺对外部气体辅助注塑成型制品翘曲与凹痕的影响

Influence of Gas-Injection Processing Conditions on Warpage and Sink Mark of Part by External Gas-Assisted Injection Molding

注塑制品翘曲变形与凹痕是2种严重缺陷,文中基于带加强筋平板制品实验研究了外部气体辅助注塑成型(EGAIM)中注气工艺参数对制品翘曲与凹痕的影响规律及原因。通过采用单因素方差分析阐明了气体注射延迟时间、气体保压压力及气体保压时间对制品的翘曲与凹痕都有显著影响,其中气体注射延迟时间的影响最显著。制品翘曲与凹痕随注气工艺参数变化呈现不同特征:随着注射延迟时间的延长,制品翘曲与凹痕呈相反的变化趋势,制品翘曲变形减小而凹痕深度增加;提高气体保压压力,制品凹痕深度单调减小而翘曲呈“U”形曲线变化;增长保压时间,制品翘曲与凹痕都有减小的趋势。这些影响规律的总结为减小EGAIM制品的翘曲与凹痕提供了依据。

The warpage and sink mark of injection molded parts are two kinds of serious defects.The effect of the gas-injection processing parameters of external gas-assisted injection molding(EG AIM)on the warpage and sink mark was investigated by the experiment of flat part with ribs.Through the single factor analysis of variance,it is shown that the gas delay time,gas holding pressure and gas holding time have significant influence on warpage and sink mark of part,and the gas delay time is the most significant effect on warpage and sink mark.With changing processing conditions,the variations of warpage and sink mark of part were summarized as follows:contrary effects,warpage decreases but sink mark increases with increasing gas delay time;sink mark is monotonously reduced and warpage varies as U shape curve with increasing gas holding pressure;both warpage and sink mark have a decreasing trend with increasing gas holding time.These results could be used to help minimize warpage and sink mark of EGAIM parts.