Research on the Deformation of Die Pins during Propellant’s Extrusion Process

The phenomenon that the holes change the position caused by the pins moving exists in 7-perforation propellant extruded by the solvent mothed. In this paper, the analysis of the forming process based on fluid-structure interaction method of mode pins moving was studied. The pressure distribution of extrusion process was analyzed and the effect of temperature and velocity on the pins deformation was analyzed. Three dimension video microscopy was used to measure the web sizes of the propellant grains. The results show that maximum deformation of die pins present a quasi-linear increase trend with the speed increase. When the entrance velocity is faster than 0.4mm·s-1, increase rate of deformation is reduced. Deformation presents linear decreasing trend with the propellant dough temperature increase. The Nitroguanidine propellant is extruded by seven-perforation die in different experiment conditions. The experimental data and numerical simulation results fit well.