At Virginia Polytechnic Institute and State University, Christopher Williams heads the effort to further advance 3-D printing with copper, a widely used conductor in electronics. Williams is using a process called binder jetting in which an inkjet printer selectively jets glue into a bed of copper powder, layer-by-layer. The printed copper product is then taken to a furnace to fuse the particles together. With support from the National Science Foundation, Williams is addressing a major challenge in the 3-D copper printing process, which is to eliminate the porosity that develops in the part during the process. Part of the National Science Foundation Series “Science Nation.”