Simulation framework for material property-based pellet formation

Plastic additives are used to strengthen the mechanical properties of polymers, improve processing efficiency, and enhance product durability, thereby enabling their use for diverse applications across many chemical industries. These additives are typically produced in powder form, however, the handling and storage of fine powders in industrial environments present significant challenges, making it is necessary to convert them into pellets. The process of pellet formation involves compression of powder under controlled pressure and temperature. Several models have been developed to explain pelletization in various fields including biomass, metals and ceramics production. However, these models have not been applied to plastic additives. Moreover, they do not account for the mechanical properties of raw materials or the transitional phase from powder to the initial compacted state. Our study focuses on developing a simulation framework based on the bulk continuum mechanics, Drucker-Prager Cap (DPC) model, which is a material- and strain-dependent for simulating pellet formation process. Although the DPC model typically requires specialized instrumented dies for radial and axial pressure measurements, we propose a method to extract material parameters from non-instrumented dies, thereby making powder compaction experiments more versatile. Using mechanical properties determined experimentally for raw powders, we modified the strain hardening relations in the DPC formulation to accurately capture the full powder-to-pellet transition. The simulated results aligned with experimental data, validating our framework for pellet formation from powdered plastic additives. Therefore, our findings may help reduce pre-production iterations, improve pellet quality, minimize material waste, and create a safer work environment.