EFFECTS OF THE SINTERING PROCESS ON ADDITIVELY MANUFACTURED COPPER PROJECTILES

Additive manufacturing (AM), particularly three-dimensional (3D) printing, has emerged as one of the fastest growing freeform fabrication techniques [1]. This form of manufacturing has spread throughout multiple industries including aerospace, automotive, and defense [1]. Among the growing range of materials available for 3D printing are plastics, ceramics, and metal/polymer composite filaments. This technique involves adding progressive layers of the material until the desired product is created. Utilizing metal/polymer composites typically requires a post-processing debinding and sintering step to fully consolidate the material into a dense metal product [2]. However, this process can be costly due to the need for hightemperature furnaces, specialized consumables, and extended processing times. Additionally, the sintering process includes complex material science, such as volumetric shrinkage, to determine relative density and deformation of the 3D printed sample [3]. This study investigates the potential for bypassing the sintering process in 3D-printed copper projectiles to evaluate the effect on key ballistic characteristics, including muzzle exit velocity, soft recovery entrance velocity, mass recovered during the soft recovery and mass lost of the projectile. This research aims to determine whether the sintering process is essential for achieving these ballistic properties successfully, or if similar performance can be achieved without it. Experimental testing will assess the performance of green and sintered AM copper 12-gauge rifled shotgun slugs. A soft recovery system was utilized to catch the projectiles while minimizing the deformation associated with recovery. Ultimately, this research will contribute to a deeper understanding of the trade-offs between post-processing requirements and performance in AM copper projectiles.