The ProMetal solid freeform process, using binder material deposited through a multi-jet printhead, selectively binds particles in a layer of metal powder. Repeated deposition of powder layers followed by binder printing builds three-dimensional shapes that may have internal channels, overhangs, and reentrant corners. The resulting green preforms consist of 60 v/o metal powder and must undergo a thermal process to achieve full density and desirable mechanical properties. Because of the low green density and relatively large particle size, achieving high density requires liquid phase sintering. This paper describes a thermal process by which 3D printed preforms are sintered to high density, and illustrates application parts.