复合固体推进剂直写式3D打印工艺及其性能

Direct-writing 3D printing technology and characteristics of composite solid propellant

开展了高固含量含能材料——复合固体推进剂的增材制造技术研究,开发出气动直写式增材制造打印系统,研制了相应的光固化三组元推进剂配方。同时,通过感度测试表明该光固化推进剂配方与普通热固化三组元配方危险等级相当,可以实现较安全打印。通过打印工艺参数的调节等大量试验研究,确定了打印头直径为1.5~2 mm,打印头直径越大精度越低,并获得了不同形状固含量75%和80%的推进剂药柱,进一步热固化后测试其抗拉强度分别为0.68、0.61 MPa,最大伸长率为31%、30%,密度为1.60、1.63 g/cm^(3),6.68 MPa下的静态燃速为5.10、8.81 mm/s。随后,采用固含量80%的推进剂配方打印了∅127 mm试验发动机药柱,成功实现地面点火,测得发动机的平均动态燃速为r—=9.034 mm/s,平均压强为p—t b=6.112 MPa。

Additive manufacturing technology of composite solid propellant was investigated.As the propellant with high solid content was energetic,the pneumatic direct-writing additive manufacturing process together with a corresponding three-component propellant formula based on photo-curing was developed.The sensitivity test results show that the photo-curing propellant formula with a risk-level equivalent to thermal curing three-component formula can be printed safely.The diameter of the print outlet is determined to be 1.5~2 mm by a large number of experiments such as the adjustment of printing process parameters,where the larger the diameter of the print outlet,the lower the accuracy.The propellant with a solid content of 75%and 80%in different shapes were obtained.After further thermal curing,the tensile strengths are 0.68 MPa and 0.61 MPa,the elongations are 31%and 30%,the densities are 1.60 g/cm^(3) and 1.63 g/cm^(3),and static burning rates under 6.68 MPa are 5.10 mm/s and 8.81 mm/s,respectively.Subsequently,the formulation with 80%solid content was used to print the∅127 mm test motor propellant grain.After assembling,the ground ignition was successfully realized with an average dynamic burning rate of r—=9.034 mm/s and an average pressure of p—t b=6.112 MPa.