3D Printer

Abstract

A method for forming an object having a three-dimensional target shape, that makes use of a build powder, a support powder and a binder. The build powder is more strongly bound by the binder than is the support powder. The build powder and the support powder are dispensed in a sequence of layers of build powder patterned with support powder that collectively form the three-dimensional shape in build powder, and the binder is applied to the deposited build powder, thereby forming the object of build powder and binder. Finally, the formed object is separated from the support powder.

1 . A method for forming an object having a three-dimensional target shape, comprising:
 a) providing a build powder, a support powder, a binder and a container and wherein said build powder is bindable by said binder and said support powder is substantially not bindable by said binder;   b) dispensing said build powder and said support powder into said container in a sequence of layers of build powder patterned with support powder that collectively form the three-dimensional shape in build powder, supported directly by support powder;   c) applying the binder to the build powder, thereby forming said object, made of build powder and binder; and;   d) separating said object from said support powder.   
     
     
         2 . The method of  claim 1 , wherein the build powder and the support powder are pourable. 
     
     
         3 . The method of  claim 1 , wherein the binder is a liquid and the build powder is wettable by the binder and the support powder is not wettable by the binder. 
     
     
         4 . The method of  claim 1 , wherein the build powder and the support powder remain substantially as solid particles when the binder is applied. 
     
     
         5 . The method of  claim 1 , wherein the binder is heated to activate the binding properties of the binder. 
     
     
         6 . The method of  claim 1 , wherein the build powder is a metal powder and the binder is a molten metal. 
     
     
         7 . The method of  claim 1 , wherein the build powder is a metal powder and the binder is a metal, and wherein the binder is applied in solid particle form followed by heating to a temperature sufficient to melt the binder. 
     
     
         8 . The method of  claim 1 , wherein the build powder is iron powder, the support powder is silicon dioxide powder, and the binder is a molten iron-carbon alloy. 
     
     
         9 . The method of  claim 1 , wherein the build powder is copper, the support powder is silicon dioxide powder, and the binder is molten copper alloy. 
     
     
         10 . The method of  claim 1 , wherein said step of dispensing said build powder and said support powder in a sequence of layers is performed by an apparatus for making three-dimensional physical objects, comprising:
 (a) a frame;   (b) a container;   (c) a build powder pourer, at least partially filled with build powder and a support powder pourer at least partially filled with support powder, each of said pourers having a dispensing opening and a dispensing plug, controllably covering said dispensing opening; and   (d) a pourer-movement and dispensing plug-actuating assembly supported by said frame over said container, and including a movement element that is selectively attachable to said build powder pourer and alternately to said support powder pourer and also capable to controllably move an attached pourer in three orthogonal dimensions and to control said dispensing plug;   (e) and at least one docking station for holding a first one of said pourers, while a second one of said pourers is attached to said movement element; and   (f) a computing assembly, including an input for receiving a target three-dimensional shape, and controlling said pourer-movement and dispensing plug-actuating assembly to move said pourers and selectively open said plugs, thereby causing powder to be poured into said container, and to thereby create in said container a sequence of layers of build powder patterned with support powder that collectively form said target shape in build powder.   
     
     
         11 . The method of  claim 10 , wherein said apparatus further includes a first refill tank and at least a second refill tank, and wherein said first and second refill tanks are disposed to dispense powder into a pourer that is held by said at least one docking station, and wherein said first refill tank contains build powder and said second refill tank contains support powder. 
     
     
         12 . The method of  claim 10 , wherein said build powder pourer is a first build powder pourer and wherein said apparatus further comprises a second build powder pourer, wherein said first build powder pourer is a fine pourer with a first sized opening, and said second build powder pourer is a fast pourer with a second sized opening that is larger than said first opening. 
     
     
         13 . The method of  claim 12 , wherein said apparatus further comprises a third build powder pourer with an opening that is a third size that is larger than said second sized opening. 
     
     
         14 . The method of  claim 11 , wherein said apparatus further includes a refill tank for each pourer. 
     
     
         15 . The method of  claim 10 , wherein said pourers each includes a plug rod; and said pourer movement and dispensing plug actuating assembly includes a plug rod actuator that moves said plug rod vertically to open and close said opening. 
     
     
         16 . The method of  claim 15 , wherein said plug rod actuator includes an electric motor for providing the force to lift said plug rod. 
     
     
         17 . The method of  claim 16 , wherein said plug rod actuator, also periodically rotates said plug rod. 
     
     
         18 . The method of  claim 10 , wherein said support powder pourer is a first support powder pourer and wherein said apparatus further comprises a second support powder pourer, wherein said first support powder pourer is a fine pourer with a first sized opening, and said second support powder pourer is a fast pourer with a second sized opening that is larger than said first opening. 
     
     
         19 . The method of  claim 18 , wherein said apparatus further comprises a third support powder pourer with an opening that is a third size that is larger than said second sized opening. 
     
     
         20 . The method of  claim 10 , wherein said movement element includes a horizontal fork that is moved into engagement with a said pourer to engage said movement element with said pourer.