Method for Reducing Layer Shifting and Smearing During 3D Printing

Abstract

An additive manufacturing system, and corresponding method, prints a sacrificial component using a 3D printing system that includes a spreading mechanism for spreading unbound powder to form layers of a powder bed and a printing mechanism for jetting binder fluid into the unbound powder to form the sacrificial component. The system forms the sacrificial component with a feature that provides a resistive force to a shear force imposed by the spreading mechanism during the spreading. The system prints a part with the 3D printing system in a coupled arrangement with the sacrificial component. The coupled arrangement in combination with the resistive force is sufficient to immobilize each printed layer of the part to resist the shear force imposed by the spreading mechanism during spreading of the unbound powder above each printed layer of the part. After printing, and before or after post-processing, the part and sacrificial component are separated.

1 . A method of forming a part via additive manufacturing, the method comprising:
 producing a model of a part, wherein a surface of the model facing in a negative z-direction includes portions that extend different amounts in the negative z-direction;
 producing a model of a sacrificial component, wherein a surface of the model facing in a positive z-direction has a complementary shape to the surface of the model facing in the negative z-direction, such that the surface of the model facing in the positive z-direction includes portions that extend different amounts in the positive z-direction; 
   forming the sacrificial component according to the model of the sacrificial component by depositing one or more layers of a loose powder and depositing a fluid onto at least a portion of each of the one or more layers of the loose powder to bind the loose powder where the fluid is deposited;   forming the part according to the model of the part by depositing a plurality of layers of the loose powder and depositing the fluid onto at least a portion of each of the plurality of layers of the loose powder; and   forming a boundary of the loose powder between the sacrificial component and the part onto which the fluid is not deposited, wherein the boundary of the loose powder separates the sacrificial component from the part.   
     
     
         2 . The method of  claim 1 , wherein a surface of the sacrificial component facing the part has a complementary shape of a surface of the part facing the sacrificial component. 
     
     
         3 . The method of  claim 1 , wherein at least a portion of the part is formed after the sacrificial component is formed. 
     
     
         4 . The method of  claim 1 , wherein the boundary of the loose powder extends through more than one layer of the plurality of layers of layers of the loose powder from which the part is formed. 
     
     
         5 . The method of  claim 1 , wherein depositing the one or more layers of the loose powder and depositing the plurality of layers of the loose powder includes spreading the loose powder using a spreading mechanism. 
     
     
         6 . The method of  claim 1 , wherein the sacrificial component extends laterally beyond the part. 
     
     
         7 . The method of  claim 1 , wherein forming the sacrificial component includes depositing a first amount of fluid at a first saturation level, wherein forming the part includes depositing a second amount of fluid at a second saturation level, and wherein the first saturation level is lower than the second saturation level. 
     
     
         8 . The method of  claim 1 , wherein forming the sacrificial component includes forming a lattice structure. 
     
     
         9 . The method of  claim 1 , wherein the boundary completely extends from a first lateral edge of the part to a second lateral edge of the part. 
     
     
         10 . The method of  claim 7 , wherein the complementary shape of the surface of the model facing in the positive z-direction enables the boundary to couple the part to the sacrificial component via an indirect mechanical coupling. 
     
     
         11 . A method of forming a part via additive manufacturing, the method comprising:
 producing a model of the part, wherein a surface of the model facing in a negative z-direction includes portions that extend different amounts in the negative z-direction;   producing a model of the sacrificial component, wherein a surface of the model facing in a positive z-direction has a complementary shape to the surface of the model facing in the negative z-direction, such that the surface of the model facing in the positive z-direction includes portions that extend different amounts in the positive z-direction;   forming the sacrificial component according to the model of the sacrificial component by depositing a first amount of fluid onto a first region of the powder to bind the powder; and   forming the part according to the model of the part by depositing a second amount of fluid onto a second region of the powder to bind the powder;   wherein a surface of the sacrificial component facing the part has a complementary shape of a surface of the part facing the sacrificial component, and wherein the powder that is disposed between the first region and the second region, is free of any deposited fluid.   
     
     
         12 . The method of  claim 11 , wherein at least a portion of the part is formed after the sacrificial component. 
     
     
         13 . The method of  claim 11 , wherein forming the sacrificial component includes depositing a first one or more layers of the powder. 
     
     
         14 . The method of  claim 13 , wherein forming the part includes depositing a second one or more layers of powder. 
     
     
         15 . The method of  claim 11 , wherein the sacrificial component extends laterally beyond the part. 
     
     
         16 . The method of  claim 11 , wherein forming the sacrificial component includes depositing the first amount of fluid at a first saturation level, wherein forming the part includes depositing the second amount of fluid at a second saturation level, and wherein the first saturation level is lower than the second saturation level. 
     
     
         17 . The method of  claim 11 , wherein forming the sacrificial component includes forming a lattice structure.