What changes occur to plastic particles during the extrusion process?

The extrusion machine heats the plastic particles to a viscous flow state. Under pressure, the plastic is forced through a die of a specific shape, resulting in a continuous body with a cross-section similar to the shape of the die. Afterward, the plastic undergoes cooling, transitioning from the viscous flow state to the elastomeric state with a certain geometry and dimensions. Finally, it cools and sets into the glassy state, yielding the desired product (glassy state - viscous flow state - elastomeric state - glassy state). In layman's terms, this process involves transitioning from granular state - mixture of granular and melted particles - melted particles - finished product.