As 3D printing is becoming more and more popular, the search for new filament materials for 3D printers is heating up. While polymers such as PLA, HDPE, and ABS are commonly used as filament materials they are not sufficiently strong for many applications. This is why materials scientists started adding fly ash microspheres to polymers to improve their strength and weight. Here are some microscale images from the improved filament material, the filament itself, and a cross section of a 3D printed part.