System and method for additive metal manufacturing

Abstract

A system for additive metal manufacturing, including a deposition mechanism, a translation mechanism mounting the deposition mechanism to the working volume, and a stage. A method for additive metal manufacturing including: selectively depositing a material carrier within the working volume; removing an additive from the material carrier; and treating the resultant material.

1 . A method for forming a physical part from a virtual part model, the method comprising:
 a) depositing a layer of metallic build material within the build volume, the build material comprising a volatile solvent;   b) removing the volatile solvent from the layer;   c) selectively machining a portion of the layer after b) within the build volume;   d) repeating a) to c) until a part with a geometry corresponding to the virtual part model is formed within the build volume; and   e) sintering the part to form the physical object.   
     
     
         2 . The method of  claim 1 , wherein the metallic build material comprises a binderless metal paste. 
     
     
         3 . The method of  claim 1 , wherein the layer is deposited onto a substrate held at a substrate temperature, the method further comprising maintaining an ambient volume proximal the layer at or below a substrate temperature throughout a) to d). 
     
     
         4 . The method of  claim 1 , wherein the portion of the layer is selectively machined by a tool, the method further comprising maintaining an ambient volume proximal the portion of the layer within an uncooled tool operating temperature range throughout a) to d), wherein maintaining the ambient volume within the uncooled tool operating temperature range evaporates the volatile solvent from the layer. 
     
     
         5 . The method of  claim 1 , wherein the metallic build material is ferrous, the method further comprising: applying an attractive magnetic force to the layer while selectively machining the portion of the layer. 
     
     
         6 . The method of  claim 5 , wherein the layer in a) is deposited onto a build plate, such that the build plate supports the part; wherein the build plate comprises an adhesive interface layer arranged between the build plate and the layer. 
     
     
         7 . The method of  claim 1 , wherein e) comprises: removing the build plate with the part from the build volume and inserting the build plate with the part into a furnace. 
     
     
         8 . A method for forming a physical object, the method comprising:
 a) depositing a layer of metallic build material onto a substrate within a build volume, the substrate having a substrate temperature;   b) selectively machining a portion of the layer within the build volume;   c) maintaining an ambient volume, adjacent the layer, at or below the substrate temperature after layer deposition until selective machining;   d) repeating a) to c) until an object precursor with precursor geometry approximating a virtual part model is formed within the build volume; and   e) sintering the object precursor to form the physical object.   
     
     
         9 . The method of  claim 8 , wherein the object precursor formed within the build volume has a predetermined geometry larger than the virtual part model, the predetermined geometry determined from the virtual part model and a predetermined shrinkage ratio. 
     
     
         10 . The method of  claim 8 , wherein the metallic build material comprises a binderless metal paste. 
     
     
         11 . The method of  claim 8 , wherein maintaining the ambient volume at or below a substrate temperature comprises maintaining the ambient volume below 100° C. 
     
     
         12 . The method of  claim 11 , wherein the metallic build material comprises a metal paste comprising a volatile solvent with a normal boiling point below 150° C., wherein maintaining the ambient volume below 100° C. evaporates the volatile solvent from the layer. 
     
     
         13 . The method of  claim 12 , wherein the metal paste further comprises a scaffold metal and an infiltrant metal. 
     
     
         14 . The method of  claim 8 , wherein the metallic build material is ferrous, the method further comprising: applying a magnetic force biasing the layer toward a build plate during a) to d). 
     
     
         15 . The method of  claim 14 , wherein the build plate comprises an adhesive interface layer adhering the layer to the build plate, wherein a layer attachment force coupling the layer to the build plate that is cooperatively generated by the magnetic force and adhesive interface layer exceeds a shear force generated while selectively machining the portion of the layer. 
     
     
         16 . The method of  claim 8 , wherein the metallic build material comprises a metal and a thermoset binder, wherein the substrate temperature is a setting temperature of the thermoset binder. 
     
     
         17 . The method of  claim 8 , wherein the portion of the layer is selectively machined by a tool; wherein maintaining the ambient volume at or below the substrate temperature further comprises maintaining the ambient volume, adjacent the machined portion of the layer, within an uncooled tool operating temperature range while the portion of the layer is selectively machined. 
     
     
         18 . An additive manufacturing system, comprising:
 a build volume;   a material deposition head arranged within the build volume;   a subtractive machining head arranged within the build volume;   a temperature control mechanism arranged within the build volume;   a control system electrically connected to the metallic build material deposition head, the subtractive machining head, and the temperature control mechanism, configured to:
 control the material deposition head to deposit a layer of metallic build material onto a substrate having a substrate temperature within the build volume; 
 control the subtractive machining head to selectively machine a portion of the layer within the build volume; and 
 control the temperature control mechanism to maintain a volume, surrounding the layer, at or below the substrate temperature after layer deposition until selective machining. 
   
     
     
         19 . The system of  claim 18 , further comprising a build plate arranged within the build volume underneath the material deposition head, wherein the control system is configured to deposit the layer of metallic build material over the build plate; wherein the build plate comprises an adhesive interface layer proximal the material deposition head. 
     
     
         20 . The system of  claim 18 , further comprising a magnetic element configured to generate an attractive magnetic force on the layer of metallic build material, wherein the metallic build material is a binderless ferrous metal paste.