Why does material extrusion most commonly use thermoplastic build materials?

Material extrusion predominantly uses thermoplastic build materials due to their ability to melt easily when heated and then retain their desired shape upon cooling. This characteristic is fundamental to the material extrusion process, where heated thermoplastics are pushed through a nozzle to form layers. After extrusion, the material cools down quickly, solidifying into the desired shape. This process allows for high efficiency and precision in 3D printing applications.

In contrast, while the other factors contribute to the selection of materials in various contexts, they do not provide the primary reason for the use of thermoplastics in material extrusion. Thermal properties, such as the ability to be reshaped upon heating and solidifying, are critical for achieving the desired dimensional accuracy and structural integrity in printed objects.