System and method for building three-dimensional objects with metal-based alloys

A digital manufacturing system for building a three-dimensional object in a layer-by-layer manner, the system comprising:

• an enclosed, insulated build chamber configured to be purged of oxygen and to be maintained at one or more temperatures of at least about 350° C. in at least a region of deposition;
• a build platform disposed within the build chamber;
• at least one extrusion line disposed outside of the build chamber and configured to receive a feedstock of a metal-based alloy and to heat the metal-based alloy to a temperature between a solidus temperature and a liquidus temperature of the alloy comprising:
• a liquefier assembly;
• a drive mechanism;
• and
• a filter positioned downstream of the liquefier assembly and configured to filter out residual impurities carried by the heated metal-based alloy;
• and
• a deposition head comprising:
• at least one extrusion tip disposed in the build chamber;
• and
• a freeze valve assembly configured to control the flow of heated metal-based alloy from one of the at least one extrusion tip;
• and
• at least one coolant solenoid disposed outside of the build chamber and configured to selectively relay a regulation flow of coolant to the freeze valve assembly.