Design And Analysis Of Nozzles For 3D Printing Experimental Systems With Energetic Materials

With the development of modern weapon,the traditional shaping methods are not adaptive in complex configuration of energetic materials,and the safety is also difficult to be guaranteed.So the free forming process,such as 3D printing,should be introduced.Considering the safety of energetic materials and being based on the traditional FDM this article put forward energetic materials 3D printing,studying material properties with energetic materials and designing a pneumatic extrusion head,which aims at energetic materials extruding and forming.Besides,a prediction model between air pressure and extrusion velocity is studied.Experiment researches were carried out to explore the rheological properties of energetic materials.The results indicated that:the viscosity and temperature is a negative correlation in the medium shear rate range and the shear rate mainly influences on the viscosity in the medium shear rate range.At low temperature,solvent ratio is negatively correlated with viscosity.At high temperature,the solvent ratio has less influence on the viscosity.Finally,constitutive models under different solvent ratio and different temperatures are obtained through analysis and fitting the rheological data.The structure design and manufacture of the extrusion head of energetic materials 3D printer were carried out.A pneumatic extrusion nozzle is developed to realize the extrusion of energetic materials and a prototype 3D printing experiment is set up finally.The temperature on preheat situation is analyzed and find that the energetic materials heated evenly.The simulation experiments of inlet pressure and structure parameters were carried out to explore the influence on extrusion velocity.The results indicated that:inlet pressure is positively correlated with extrusion velocity and length of molding is negatively correlated with extrusion velocity.With the increasement of transition angle and nozzle diameter,there is no monotonous trend of extrusion velocity and an optimize point which gets maximum extrusion velocity.By using the experiment date,a prediction model between extrusion velocity and other factors is found through multi variates linear regression.The prediction model is verified its saliency.Eventually the energetic materials sample is printed according to the match of predicted extrusion velocity and print parameters.