微注射成形制品质量影响因素分析

在不同工艺条件下进行聚合物和粉末微注射成形试验，制得微米级的聚丙烯和二氧化锆陶瓷微结构，微型腔采用感应耦合等离子深槽刻蚀技术在硅模具镶块上加工。分析微注射成形工艺及硅模具对微结构的填充、尺寸精度及表面质量的影响。不合理的工艺参数容易导致微结构出现填充不足、表面粗糙、气孔等缺陷，提高模具温度和注射压力以及注射前模具抽真空有利于微型腔的填充，模具抽真空还可以改善微结构件的表面质量。深槽刻蚀后的硅模具表面粗糙度为0.31 μm，填充完好的聚丙烯微结构及陶瓷微结构素坯表面粗糙度不再受注射工艺参数的影响，其值近似于刻蚀后的硅模具，亚微米级粉末的使用可以明显改善烧结后陶瓷微结构的表面粗糙度。

Analysis of the Effects on the Quality of Micro Injection Molded Products

Polypropylene and ZrO_2 microstructures are fabricated respectively by polymer and powder micro injection molding under different process conditions. Microcavities in silicon mold insert are manufactured by inductively coupled plasma (ICP) etching process. The effects of process conditions and silicon mold on the filling performance, dimensional accuracy and surface quality of microstructures are detailedly investigated. Inappropriate injection conditions will induce many defects such as underfill, rough surface and hollow. Microstructures can be filled completely by raising mold temperature and injection pressure and by vacuuming the mold before injection, and the latter can also improve the surface quality of microstructures. The roughness of etched silicon mold surface is about 0.31 μm. If microcavities are filled completely, the effect of injection parameters on the surface roughness of polymer and ceramic green microstructures is neglectable. They have approximate roughness with silicon mold. Sub-micron ZrO_2 powder can improve the surface roughness of sintered ceramic microstructures.