FDM型3D打印喷头的传热结构分析与设计

熔融沉积型3D打印喷头传热结构温度场对塑料熔丝的流变状态具有较大的影响。对其隔热段塑料熔丝温变特性及其造成的运维问题,进行了机头热流分析计算、熔丝实例收集与分析。提出并设计了基于阻热和热流改向的T型组件、多层套管送料等结构,与隔热段熔丝温度急变特性相匹配。在大幅面打印机实验中,热感成像仪温度场显示,T型组件热阱平面上侧温度不高于60℃,散热段铁氟龙内外管温度均不高于50℃,低于其玻璃态转化温度,实测冷开机打印、长时持续打印效果良好。阻热和热流改向结构根本性地改变了打印喷头传热温度场,在化工填料用大幅面3D打印机应用中具有重要意义。

Analysis and Design of Heat Transfer Structure of FDM 3D Printing Nozzle

The temperature field of the heat transfer structure of the fused deposition type 3D print head had a great influence on the rheological state of the plastic fuse.According to the temperature change characteristics of the plastic fuse in the thermal insulation section and the operation and maintenance problems caused by the thermal insulation section,the heat flow analysis and calculation,the fuse collection and analysis were carried out.The structure of T-type components and multilayer casing feeding based on heat-resistance and heat flow redirection was proposed and designed to match the rapid temperature change characteristics of the insulation section.In the experiment of large-scale printer,the temperature field of thermal imager showed that the temperature of the upper side of T-type heat sink plane was not higher than 60℃,and the temperature of the inner and outer tubes of teflon in radiation section was not higher than 50℃,which was lower than glass transition temperature.The results of cold start-up printing and long-term continuous printing were good.Heat resistance and heat flow structure fundamentally change heat transfer temperature field of printing nozzle,which was great significance to application of large-scale 3D printer in chemical engineering packing production.