Li Jiquan, Ma Haowei, Liu Wenyong, Jiang Shaofei, Pan Baisong
College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310014, China.
National International Joint Research Center of Special Purpose Equipment and Advanced Processing Technology, Zhejiang University of Technology, Hangzhou 310014, China.
Polymers (Basel). 2023 Jan 8;15(2):326. doi: 10.3390/polym15020326.
In micro injection molding, the cavity thickness and surface roughness are the main effects factors of polymer flow in the die designing and affect the quality of molded products significantly. In this study, the effects of cavity thickness and roughness of cavity surface were investigated mainly on polymer flow during molding and on the roughness of molded products. The parts were molded in the cavities with the thickness from 0.05 mm to 0.25 mm and surface roughness from R = 46.55 nm to R = 462.57 nm, respectively. The filling integrities and roughness replication ratio of molded parts were used to evaluate the statements of polymer flow and microstructure replication during micro injection molding, respectively. The results showed that the filling integrity changing trends in the thinner cavities were obviously different or even opposite to those in the thicker cavities with the changing of cavity surface roughness instead of single trend in the conventional studies. For each cavity surface roughness, the filling integrity showed an upward trend with the increasing cavity thickness. In different cavity thickness, the maximum gap of filling integrity was 23.76 mm, reaching 544.94% from 0.05 mm to 0.25 mm. Additionally, the surface roughness ratio was slightly smaller than one before, reaching the polymer surface roughness limit around R = 71.27 nm, which was decided by the nature of the polymer itself. This study proposed the references for the design and fabrication of mold cavities and parts, and saved time and cost in the actual product manufacturing.
在微注塑成型中，型腔厚度和表面粗糙度是模具设计中影响聚合物流动的主要因素，对成型产品质量有显著影响。本研究主要考察了型腔厚度和型腔表面粗糙度对成型过程中聚合物流动以及成型产品粗糙度的影响。分别在厚度为0.05mm至0.25mm、表面粗糙度从R = 46.55nm至R = 462.57nm的型腔内成型零件。利用成型零件的填充完整性和粗糙度复制率分别评估微注塑成型过程中聚合物流动和微观结构复制情况。结果表明，随着型腔表面粗糙度的变化，较薄型腔内的填充完整性变化趋势与较厚型腔内明显不同甚至相反，并非传统研究中的单一趋势。对于每个型腔表面粗糙度，填充完整性随型腔厚度增加呈上升趋势。在不同型腔厚度下，填充完整性的最大差值为23.76mm，从0.05mm到0.25mm增幅达544.94%。此外，表面粗糙度比略小于之前，在聚合物表面粗糙度极限R = 71.27nm左右达到该极限，这由聚合物本身性质决定。本研究为模具型腔和零件的设计与制造提供了参考，在实际产品制造中节省了时间和成本。
