Laser sintering of electrohydrodynamic inkjet-printed silver in microgravity for in-space manufacturing of electronic devices.

The National Aeronautics and Space Administration (NASA) plans to deploy a fully functional 3D printer in low Earth orbit for in-space manufacturing (ISM) of semiconductor electronics. Earlier, our group demonstrated the successful application of high-resolution printing for semiconductor manufacturing using electrohydrodynamic printing. However, sintering of printed films is a significant challenge due to payload constraints. In this paper, we demonstrate laser sintering as a viable technology for ISM. The first experiments of successful demonstration of laser sintering of EHD printed silver on silicon in micro and lunar gravity are presented. The microstructures and conductivity of the samples are compared to those of the ground samples, and we observe that samples under microgravity exhibit increased heat transport compared to those under gravity. We hypothesize that the samples under microgravity experience lower convective heat transport, resulting in increased surface melting. A COMSOL heat transport model supports the laser sintering studies and hypotheses.