- 01: Introduction
- 02: History
- 03: Propellants, Firearms, and Ammunition Development
- 04: Modern Firearms Manufacture
- 05: Small Arms Ammunition
- 06: Evidence Handling Procedures
- 07: Equipment and Instrumentation
- 08: Examination of Firearms
- 09: Cartridge and Shotshell Examination
- 10: Characterization and Evaluation of Fired Projectiles
- 11: Bullet Comparison and Identification
- 12: Gunshot Residue and Distance Determination
- 13: Toolmark Identification
- 14: Communicating Results
- Resources
Die Extrusion
Home > Small Arms Ammunition > Components > Die Extrusion
Processing the plasticized nitrocellulose mass combines extrusion with rotating cutters to produce the desired shape. Cutters rotate in a plane flush with the exit nozzle of the extrusion die. By varying the size of the extrusion holes, the rate of extrusion, and the speed of the cutter rotation, the manufacturer can produce cylindrical or disk/flake shapes.
A slow extrusion rate combined with a high cutter rotation speed produces disk/flake propellants. A fast extrusion rate with a slow cutter speed produces cylinders.
Extruding sticky pieces of nitrocellulose into air would result in another mass of nitrocellulose. To avoid this, the extrusion nozzle and cutter assembly are submerged in a tank filled with a liquid that will not degrade the material. This floats cut pieces away from the cutter without their sticking together.
Click here to watch an animation on die extrusion.
