一种FDM成形中气体辅助喷头的设计及其对打印件力学性能的影响

Design of a gas-assisted nozzle in FDM molding and its influence on mechanical properties of printing parts

以聚乳酸为原料,设计了一种基于熔融堆积成形技术的3D打印机气体辅助喷头,通过输入高温高压气体施加于打印表层,促进层间大分子链互相扩散、渗透以及缠结,进而通过热压粘合作用,提高了打印件的层间机械强度。采用正交试验,对气体流量和气体压力对打印件力学性能的影响进行了研究。结果表明,随着气体流量和气体压力的提高,打印件的层间结合强度均呈先增大后减小的趋势,且在气体流量为1.75 L·min^(-1)、气体压力为0.40 MPa时平均拉伸强度最大为40.0 MPa,比无气体辅助环境下的拉伸强度提高了115.1%。表明对打印表面施加高温高压的热气流可显著提高打印件的拉伸性能,验证了所设计的气体辅助喷头的可行性。

Using the polylactide as raw material,a gas-assisted nozzle of 3D printer based on fused deposition modeling(FDM)technol-ogy was designed.The input of high temperature and high pressure gas was applied to the printing surface to promote the interlayer diffu-sion,penetration and entanglement of macro molecular chains,and the interlayer mechanical strength of the printed parts was improved by hot pressing bonding.The effects of gas flow and gas pressure on the mechanical properties of the printed parts were studied by orthogonal tests.The results show that with the increase of gas flow and gas pressure,the interlayer bonding strength of the printed parts increases first and then decreases,and the maximum value of average tensile strength is 40.0 MPa when the gas flow rate is 1.75 L·min^(-1) and the gas pressure is 0.40 MPa,which is 115.1%higher than that in the non-gas-assisted environment.It is shown that applying high tempera-ture and high pressure hot gas flow on the printing surface can significantly improve the tensile properties of the printed parts,which verifies the feasibility of the designed gas-assisted nozzle.