直写式3D打印硅橡胶泡沫压缩力学性能实验研究

Experimental study on compressive mechanical properties of silicone rubber foam for direct ink writing 3D printing

通过电镜对比分析了直写式3D打印制备的硅泡沫与传统化学发泡法的硅泡沫微观结构,表明直写式3D打印硅泡沫结构具有结构高度有序、泡孔结构可控的特点,在压缩力学性能定制化设计方面具有巨大的潜力。通过2种典型直写式3D打印硅橡胶泡沫材料(简单立方结构、面心立方结构),研究了泡孔结构、胶丝间距、胶丝直径及打印层数等关键打印参数对其压缩力学性能影响。结果表明,对于2种结构胶丝间距变大或胶丝直径减小均会降低其工作平台区应力中值,使平台区应力变化更为平缓;打印层数的增加对平台区应力差值的影响比对应力中值的影响更为显著,更有利于其压缩性能的提升。实验结果可为3D打印硅橡胶泡沫材料的结构设计及力学性能定制提供技术支撑。

The micro-structures of silicon foams manufactured by traditional chemical foaming method and direct ink writing(DIW)were observed via electron microscope in this paper.The results indicate that the structure of DIW silicon foam can be highly ordered and controllable,which shows great potential for customized design of compression mechanical properties.Meanwhile,two typical silicone rubber foams(simple cubic structure or face centered tetragonal structure)were manufactured by DIW 3D printer built by the research team.The influence of key printing parameters,including cellular structure,filament spacing,filament diameter and number of printing layers,on their compression mechanical properties were researched through experiments.Results show that for the two types of silicone foams mentioned above,the wider filament spacing or the thinner filament diameter will reduce both the median stress and the change rate of stress in the stress platform area.And increasing the number of printing layers has a more observably affect on the stress difference of the platform compared with the median stress,which benefits the improvement of compression mechanical properties of silicone rubber foams.The analysis of the experimental results provides technical support for structural design and customization of compression mechanical properties for 3D printed silicone rubber foams.