基于空气动力学透镜的线性聚焦3D打印送粉喷头设计与性能研究

Design and Performance Research of Linear Focus 3D Printing Powder Nozzle Based on Aerodynamic Lens

提出一种基于“空气动力学透镜”的具有粉末线性聚焦功能的新型3D打印送粉喷头,可以使粉末流在喷头出口一定距离内均保持汇聚状态。设计了该新型喷头的内腔结构,建立了粉末颗粒在喷头中的汇聚运动模型,分析了颗粒运动的斯托克斯数S、空气动力学透镜第一节孔径df、孔径收缩率δ以及粉末进入喷头的入射角α对粉末颗粒聚焦性能的影响。研究结果表明:对于粒径为15~25μm的316L颗粒,该喷头可以将粉末颗粒聚焦成半径1.55 mm的粉末流,且在喷嘴外20 mm范围内均保持良好的汇聚状态;实验结果和计算结果基本一致。该新型空气动力学透镜3D打印送粉喷头的颗粒汇聚性能明显优于传统喷头,对于促进沉积增材制造的灵活性和适用性具有重要意义。

A new type of 3D printing powder feeding nozzle with linear focusing based on“aerodynamic lens”is proposed,which can keep the powder stream in a convergent state within a certain distance from the nozzle outlet.The inner structure of the nozzle is designed,and the convergent movement model of powder particles in the nozzle is established.These factors are analyzed for studying the focusing performance of the powder particles:the Stokes number of the particle(S),the first aerodynamic lens aperture(df),the aperture shrinkage(δ)and the incident angle of the powder entering the nozzle(α).The research results show that for 316L particles with a particle size of 15-25μm,the nozzle can focus the particles into a powder stream with a radius of 1.55 mm,and the powder stream maintains a good convergence state within 20 mm outside the nozzle.The numerical results are basically consistent with the experimental ones.The particle aggregation performance of the new aerodynamic lens 3D printing powder feeding nozzle is significantly better than that of the traditional nozzle,which is of great significance to promote the flexibility and adaptability of deposition additive manufacturing.