Large, Hollow Metal Parts by 3D Printing Goal: The goal of this program is to enable the use of 3D Printing for the direct fabrication of large (>.5m) metal parts. The focus will be on structural parts which take advantage of the ability to create complex internal geometry, including truss structures, ribs, etc. The direct fabrication of structural metal components in small and moderate quantity will greatly extend the range of applications of SFF. Approach: Metal parts will be fabricated directly using metal powder. The key to the fabrication of large parts is to minimize the shrinkage during furnace post-processing (after the printing step). The primary thrust is to infiltrate the 3D Printed skeleton so as to densify it with little shrinkage. While such infiltration has been the standard practice in the densification of metal parts made by 3D Printing, this project seeks to make parts of homogeneous composition by such densification. (Structural applications often demand parts of homogeneous composition.) Sponsor: Office of Naval Research Copyright 1989-2000, 3DPTM Laboratory, MIT