In industry, the usual method is to add all the materials at the same time, using separate parallel injection channels. Therefore, we also considered a second material injection method called "simultaneous injection scenario", which consists of inserting AM and BC particles at the same time, side to side (see Fig. , right). We maintain the same mass ratio and number of particles as in the sequential injection scenario, inserting a number of AM and BC particles in parallel and at a constant injection rate until the total number of particles is reached. In these two material injection scenarios, the total number of AM and BC particles are the same, only the insertion timing is different. In order to know the number of AM and BC particles needed for the extruder model, we tested the volume capacity of the extruder by filling it with BC particles. We obtained an approximate number of BC particles that could occupy the extruder thanks to their smaller radius. We then calculated the initial volume of these BC particles, which was larger than their volume inside the extruder due to the overlap between particles in the DEM model. We used the calculated BC particle volume as the estimated total initial volume of AM and BC particles, i.e., 4 × 10 -5 cm 3 . Based on the known particle radius, density, and mass ratio (given by the lab experiments), we can obtain the total number of AM and BC particles. As a result, there are 442 thousand BC particles and 21.2 thousand AM particles inside the extruder at the end of the particle insertion process.