Final answer:
Blowing agents are mixed into the filaments before extrusion, allowing them to survive the manufacturing process. When the filaments are extruded, the blowing agents cause the structure to foam and have a lower density. This process helps create lightweight objects.
Step-by-step explanation:
The blowing agents survive the manufacturing process because they are mixed into the special 3D printer filaments before extrusion. These agents are small molecules that can diffuse through the material and be released into the environment. When the filaments are extruded, the blowing agents cause the filament to foam, resulting in a lower density structure. This process allows for the creation of lightweight objects with lower material usage.