针对微注塑成型过程中排气对塑件成型质量的影响,以细胞皿为研究对象,设计了带有抽真空装置的微注塑模具,通过测试,真空度达到-0.098 MPa.分别以聚丙烯（PP）和高密度聚乙烯（HDPE）进行成型工艺试验,当模具型腔未开设排气装置时,塑件流动前沿严重烧焦,严重影响了塑件质量.当有排气槽未抽真空时,在塑件的表面形成了微孔和暗纹;当抽真空时,塑件表面较光顺,成型质量较好.可见微型腔加工精度较高,熔体充模流动时气体不易排出,对熔体充填流动会产生严重影响,采用抽真空工艺对提高微塑件的成型质量至关重要.
A cell container mold with vacuum system is designed to investigate the impact of vacuum on the quality of parts during micro injection molding.The vacuum degree of mold can be to-0.098 MPa.The molding process is carried out respectively with polypropylene（PP）and high density polyethylene（HDPE）. If there is no exhausting unit,the flow frontier of polymer melt is scorched seriously and the quality of parts is influenced severely.If the exhaust grooves are machined but no vacuumed,there are microporous and shadow weave around the surface of plastics.However,when vacuumed,the satisfactory molding quality of parts can be obtained.It is obvious that the air in mold cavity is difficult to be exhausted,so that vacuuming is very significant to improve the molding quality of products.
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