圆管件溢流法流体辅助注塑实验分析

Experimental Study of Overflow Fluid-assisted Injection Molding Circular Tubes

基于自行构建的流体辅助注塑实验平台,对圆管件的溢流法气体辅助注塑(GAIM)和水辅助注塑(WAIM)进行了实验研究。比较了辅助介质、型腔截面大小对管件内表面质量、残留壁厚大小、变化和波动的影响规律,并分析了其影响机理。实验发现,WAIM圆管件内壁光滑,而GAIM圆管件的内壁面存在"发泡"倾向,型腔截面越大,发泡越严重;残留壁厚随型腔截面增大而变厚,但穿透率变化很小;小型腔截面,残留壁厚沿穿透方向变薄;大型腔截面,残留壁厚受较小的溢流口的影响而沿穿透方向变厚;与GAIM圆管件相比,WAIM圆管件的残留壁厚存在较明显的波动;溢流口截面相对型腔截面的突然变小对型腔末端的残留壁厚影响很大,应该流线过渡。

Experimental study of gas assisted injection molding （ injection molding （WAIM） were carried out based on a lab-developed GAIM ） and water fluid assisted FAIM system. The influences of different fluid and the cross-section size of cavity on the inner quality of parts and residual wall thickness （RWT） were compared and analyzed as well as the impact mechanism. The experimental results showed that： the WAIM molded parts had a smooth inner surface, while the GAIM molded parts had a trend to foam in the internal surface. The bigger the cross-section size was, the more severe to foam. Increasing the crosssection size could increase the RWT, while the penetration ratios varied little. WAIM can be used to produce parts with thinner RWT. The RWT of FAIM sample with small cross section size tended to thin along the penetration direction, while that of large cross section tended to thick along the penetration direction for the sharp change of cross section between the end of cavity and the overflow channel. Compared with the GAIM, there were obvious fluctuations in the RWT of WAIM parts for the water cooling. The end of cavity should be streamline transited to the overflow channel to obtain even RWT.