I hope you are not a child abused by insects, roasting them with a magnifying glass. But you already know that this is possible. Artist Marcus Kaiser doing something similar, only instead of fried ants had sand, and instead of the usual magnifiers - a large Fresnel lens.
His printer was named SolarSinter. It prints three-dimensional objects in the sand.
The concept is similar to a conventional laser sintering 3D printer, but SolarSinter much less accurate than laser. But do not forget, this is Marcus - an artist, not a scientist, and its development is done for the sake of art, and not to create prosthetic knee joint or vertebral
Yes, this video is two years. But he stumbled on Techcrunch and then I - just today.