【摘要】 为开发适宜打印PPS(聚苯硫醚)等高温工程塑料的FDM-3D打印喷头，基于传热学和流体力学，利用Fluent软件，建立不同尺寸的喷嘴和喉管的有限元模型，通过传热、流动仿真获得温度场与压力场并进行理论分析。仿真和分析结果表明，喉管散热效果随着壁厚的减小和中间段长度的增加而得到改善，在此基础上，对传统喉管的结构进行优化，壁厚由0.6 mm减小至0.4 mm,将中间段长度由1.5 mm增加至2 mm,喉管温度分布在满足性能要求的同时，需要避免应力集中造成变形。喷嘴流道进出口压差随着渐缩段锥形角度的减小而减小，将渐缩段锥形角度由传统喷嘴的120°减小至60°,压差提升了12.7%,较好地满足了性能要求。最后，成型效果对比实验结果表明，优化后的喷头打印出的工件表面质量得到提升，三维方向上尺寸误差降低至80%以下，证明了结构优化的有效性。更多还原

【Abstract】 To develop an FDM-3D printing nozzle suitable for printing high-temperature engineering plastics such as PPS(polyphenylene sulfide), a finite element model of nozzles and venturi with different sizes was established based on heat transfer and fluid mechanics using Fluent software. The temperature field and pressure field were obtained through heat transfer and flow simulation and theoretical analysis was conducted. The simulation and analysis results showed that the heat dissipation effect of the venturi was improved with the decrease of wall thickness and the increase of the length of the middle section. Based on this, the structure of the traditional venturi was optimized. The wall thickness was reduced from 0.6 mm to 0.4 mm, and the length of the middle section was increased from 1.5 mm to 2 mm, so that the temperature distribution of the venturi could meet the performance requirements while avoiding deformation caused by stress concentration. The pressure difference between the inlet and outlet of the nozzle flow channel decreased with the decrease of the conical angle of the tapered section. The conical angle of the tapered section was reduced from 120° of the traditional nozzle to 60°, increasing the pressure difference by 12.7%, which better met the performance requirements. Finally, the comparative experimental results of the molding effect showed that, the surface quality of the workpiece printed by the optimized nozzle was improved, and the dimensional error in the three-dimensional direction was reduced by more than 80%, verifying the effectiveness of the structural optimization.更多还原