Study Of Integrated Printing And Forming Technology For DNTF-based Micro-explosion Transmitted Devices

Microelectromechanical systems（Micro Electronic Mechanical Systems,MEMS）pyrotechnics with features such as transducer informatization,structure miniaturization and sequence integration meet the development needs of modern weapon systems miniaturization,informatization and intelligence.Micro-explosion devices as an important part of the MEMS detonation system,its micro-scale charging,automation and rapid manufacturing is still a challenge.In view of the current problems faced by micro-detonation devices,this paper proposed a scheme based on multi-material inkjet printing to realize the integrated printing and molding of the charge-shell structure,mainly studying the design and molding performance of the energetic ink formulation,the design and molding performance of the shell ink and the integrated printing and molding of the charge-shell,and finally characterizing and analyzing the microscopic morphology,adhesion performance and detonation performance of the charge-shell integrated molding samples.The main contents of the study are as follows:（1）With 3,4-dinitrofurazanfuroxan（DNTF）as the main explosive,polydimethylsiloxane（PDMS）and ethylcellulose（EC）as the binder system,the effects of binder content on the intermolecular binding energy,mechanical properties and cohesive energy density of DNTF/PDMS-EC system were investigated by molecular dynamics simulation,and the optimal binder content was analyzed and determined.The results demonstrated that as the binder content in the composite system gradually increased,the binding energy,cohesive energy density and mechanical properties of the system showed a pattern of first increase and then decrease.The binder content was determined to be 10%for the follow-up study.（2）Ethyl acetate was selected as the solvent to design and formulate DNTF-based energetic ink,and the effects of different mass ratios of two-component binder on the rheological properties and printability of the energetic ink were investigated to determine the formulation of the energetic ink.The optimum process parameters were determined as follows:air inlet pressure 0.1 MPa,pulse 0.29ms and stroke 43%.The moulded samples were characterised and analysed by using scanning electron microscopy（SEM）,X-ray diffractometer（XRD）,differential thermal scanner（DTA）,nanoindenter,impact sensitometer and friction sensitometer to evaluate the performance of the moulded samples in terms of forming performance,microscopic morphology,mechanical sensitivity,mechanical properties and detonation properties.The test results showed that the microstructure of the molded samples was dense and the molding effect was good,and the crystalline shape of the samples did not change during the preparation of ink jet printing.The modulus of elasticity and hardness of the compound reached 9.865 GPa and 0.181 GPa,respectively.And the sample adhesion is also better;DNTF-based explosives ink molding sample critical detonation thickness of 0.15mm,detonation velocity up to 7720m·s^-1,which was 91.6%of the theoretical detonation velocity.（3）A shell ink with bisphenol A epoxy resin（E51）and curing agent isophorone diamine（IPDA）as the substrate and nanoscale fumed silica as the ink rheological property modifier was designed,as well as to investigate the effect of silica content on the ink rheological properties and deposition morphology.The optimal process parameters were also determined:The cycle,print speed and substrate temperature are 5 ms,45 m·ms^-1 and 50°C respectively.By using SEM,scanning infrared instrument and universal testing machine,the microstructure,extent of curing and mechanical properties of the formed samples were tested and analysed.The results demonstrated that the microstructure of the samples was dense,the epoxy groups had reacted completely and the mechanical properties of the inkjet printed samples were superior compared to those of die cured samples.（4）The samples were prepared with energetic inks and shell inks,and then the samples were characterized and analyzed for their microscopic morphology,adhesion properties,and bursting properties by means of co-printing with dual nozzles.The results showed that the contact interface between the pyrotechnic agent and the shell was closely stacked and the molding effect was good.At the same time,the adhesion strength between the two reached 4B,and the ability to transmit the detonation in the micro-scale,which verified the feasibility of the preparation of the integrated structure of the charge-shell of the micro-detonation device.