In a co-extrusion process, there are typically multiple extruders, each responsible for melting and extruding a different material. These materials can have distinct properties, such as color, strength, flexibility, or barrier characteristics.

The co-extrusion die head is designed with a specific geometry that allows the molten materials from the different extruders to come together within the die head without mixing or blending. The die head has channels and pathways that maintain the separation of the layers as they flow toward the exit.

The combined materials flow through the die head and emerge as a single multilayered structure, with each layer maintaining its individual properties. These layers remain distinct and do not intermingle because of the design and precision of the co-extrusion die head.