Simulation of printer nozzle for 3D printing TNT/HMX based melt-cast explosive

Huzeng Zong,Wei Jiang,Lei Xiao,Yubing Hu,Yanjun Hao,Qilun Cong,Tengyue Zhang,Hu Guo,Gazi Hao,Guangpu Zhang

doi:10.1007/s00170-021-08593-z

Abstract

Fused deposition modeling (FDM) as one of the additive manufacturing (AM) technologies has been widely used in various manufacturing industries to fabricate products with complex structures; however, the application of FDM in energetic materials (EMs) was still less common. In this work, the effect of HMX solid content and particle size on the viscosity of molten TNT/HMX explosives were investigated. Then, the computational fluid dynamics (CFD) and discrete element method (DEM) were used to simulate the influence of viscosity, pressure, temperature, nozzle diameter, and particles on the fluid flow inside the 3D printer nozzle. In addition, an FDM 3D printer was used to prepare TNT/HMX-based explosives, and various characterization methods were applied to explore the structure and morphology of printed samples. This work provided guidelines for FDM technology to fabricate EMs and proved that FDM was more suitable than the conventional melt-casting method to prepare explosives with high viscosity and special-shaped structures.

Highlights

Fused deposition modelling (FDM), as a kind of rapid prototyping technology, is one of the most widely used methods for rapid prototyping in the world and developed by Scott Cump of Stratasys
The results show that 3D printing melt-cast explosives have more compacting internal structures with the density of 1.65 g/cm3, the compressive strength of 5.56 MPa, and the detonation velocity of 7143 m/s [21]
In order to simulate the temperature distribution of the nozzle shell during printing, the 3D model of the nozzle was designed in SolidWorks software according to actual measured size, the initial geometry of the object was constructed and meshed, the total length of nozzle was 14.4 mm, the diameter of inlet was 4 mm, and that of outlet was 0.58 mm

Summary

Introduction

FDM, as a kind of rapid prototyping technology, is one of the most widely used methods for rapid prototyping in the world and developed by Scott Cump of Stratasys. The physical process of FDM method was a thermoplastic polymer is used to print layers of materials. An excellent advantage of FDM is that it can be used to create objects fabricated from multiple material types by printing and subsequently changing the print material, which enables more producer control over device fabrication for experimental use. Besides conventional materials such as PC [13], polystyrene (PS) [14], ABS [15], FDM can be used to print 3D models by using metal [16], ceramics [17] and biomaterials [18]. FDM 3D printing technology can be applied in many fields, including energetic materials

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Results

Conclusion