PDMS/SiC功能梯度复合材料3D打印主动混合喷头结构设计与工艺参数优化

Structure design and process parameter optimization of active mixing nozzle based on PDMS/SiC functional gradient composite

以高黏度材料聚二甲基硅氧烷(PDMS)和碳化硅(SiC)粉末混合液为例,利用流体动力学仿真模拟,设计并优化主动混合喷头。仿真分析不同螺杆结构对主动混合喷头混合效果的影响,选定双向四螺旋螺杆结构,同时探究了螺杆长度、螺杆与腔体间隙等结构参数对混合效果的影响规律,确定螺杆长度为12 mm、螺杆与腔体间隙为0.2 mm;优化了该结构的转速、入口速度等工艺参数,确定转速为60 r/min、入口速度为1 mm/s。此外分析了该结构在不同材料体积配比下均可进行有效混合。最后,通过打印试样,验证了该主动混合喷头能够实现复合材料的有效混合。

Taking the mixture of high⁃viscose polydimethylsiloxane(PDMS)and silicon carbide(SiC)powders as an example,the active mixing nozzle was designed and optimized through hydrodynamic simulation.The influence of different screw structures on the mixing effect of active mixing nozzle was analyzed through simulation.The bidirectional quad⁃screw structure was selected to explore the effect of structural parameters such as screw length,screw and cavity clearance on the mixing effect.The screw length and the gap between screw and cavity were determined to be 12 and 0.2 mm,respectively.The rotation speed and inlet speed of the structure were optimized,and the rotation speed and inlet speed were determined to be 60 r/min and as 1 mm/s,respectively.In addition,the structure can be mixed effectively under different material volume ratio based on the analysis results.Through printing samples,it was confirmed that the effective mixing of composite materials could be realized by using the active mixing nozzle.