Gas shielding structure for use in solid free form fabrication systems

A solid free form fabrication (SFF) system for fabricating three-dimensional structures in a continuous manner with successive layers of a feedstock material comprising:

• a plasma discharge positioned to emit a plasma stream in a plasma path;
• a feedstock feed mechanism operable to feed the feedstock material into the plasma path of the plasma discharge;
• a positioning arm coupled to the plasma discharge and the feedstock feed mechanism to form a deposition head, whereby the positioning arm is positionable to align the deposition head with a targeted region to fabricate a three-dimensional structure by transferring the feedstock material from the feedstock feed mechanism to the targeted region in a controlled manner by melting the feedstock material at a deposition point and allowing it to re-solidify at the targeted region;
• a control platform coupled to the positioning arm, the control platform including a plurality of control components, whereby a plurality of customizable control parameters are input into the plurality of control components and provide positioning and repositioning of the positioning arm and operation of the deposition head;
• and
• a three-dimensional gas shielding structure positioned to encompass at least the deposition head and the targeted region to protect the targeted region from oxidation, the gas shielding structure configured as a discrete parallelepiped structure having a substantially open periphery to provide saddling of the gas shielding structure over and about at least the targeted region to provide three-dimensional shielding, the structure further having openings formed therein an uppermost edge surface for positioning of the deposition head therethrough.

A solid free form fabrication (SFF) method for fabricating three-dimensional structures in a continuous manner with successive layers of a feedstock material, the method comprising the steps of:

• providing a positioning arm including a deposition head mounted thereto, the deposition head creating a plasma stream in a plasma path;
• feeding the feedstock material into the plasma path;
• providing a plurality of control components coupled to a control platform, whereby the positioning arm is coupled to the control platform, the plurality of control components are programmable to control the positioning arm whereby a plurality of customizable control parameters are input into the plurality of control components, the plurality of customizable control parameters configured to maintain current amperage and travel speed such that an energy level of the plasma stream is optimized to fuse the feedstock material at a predetermined targeted region;
• positioning a gas shielding structure to substantially encompass the deposition head and at least the predetermined targeted region of a three-dimensional structure, the gas shielding structure configured as a discrete parallelepiped structure having a substantially open periphery to provide saddling of the gas shielding structure over and about at least the targeted region to provide three-dimensional shielding, the structure further having openings formed therein an uppermost edge surface for positioning of the deposition head therethrough;
• and
• positioning the positioning arm to align the deposition head relative to the predetermined targeted region to fabricate the three-dimensional structure in the predetermined targeted region.