Process for Strengthening Porous 3D Printed Objects

Abstract

A composite body includes a bound mixture, a resin and a coating. The bound mixture includes a binder and a plurality of particles. The resin fully infiltrates the bound mixture such that the resin fully infiltrates an entire thickness of the bound mixture. The composite body is formed by combining a plurality of particles with a binder to form a bound mixture and infiltrating the bound mixture with a resin to a depth such that substantially an entire thickness of the bound mixture contains the resin. The coating defines an outer layer of the composite body.

1 . A composite body comprising:
 a 3D printed bound mixture including a binder and sand;   a resin infiltrating the bound mixture to strengthen the bound mixture; and   a coating applied to an outer surface of the bound mixture strengthened by the resin.   
     
     
         2 . The composite body of  claim 1 , wherein the coating infiltrates at least a portion of the bound mixture. 
     
     
         3 . The composite body of  claim 1 , wherein the bound mixture is formed into a predetermined shape. 
     
     
         4 . The composite body of  claim 3 , wherein the predetermined shape is a sacrificial tool. 
     
     
         5 . The composite body of  claim 3 , wherein the predetermined shape corresponds to a 3D computer model. 
     
     
         6 . The composite body of  claim 1 , wherein either or both of inner and outer surfaces of the bound mixture is infiltrated with the resin, 
     
     
         7 . The composite body of  claim 1 , wherein the bound mixture defines pores into which the resin is infiltrated, the resin filling a plurality of pores of the bound mixture. 
     
     
         8 . The composite body of  claim 1 , wherein an inner surface of the bound mixture is less porous than an outer surface of the bound mixture. 
     
     
         9 . The composite body of  claim 1 , wherein the coating includes a filler being one of ceramic powder, metal powder, plastic powder, and metal fillings. 
     
     
         10 . The composite body of  claim 1 , wherein the coating has a first thickness less than a second thickness defined by the bound mixture. 
     
     
         11 . The composite body of  claim 1 , wherein the coating is applied to an outer surface of the bound mixture by any one or any combination of a spray metallization, fiber strands, a fiber weave, metal plating, and dry powders. 
     
     
         12 . The composite body of  claim 1 , wherein the binder is one part of a two-part curable resin. 
     
     
         13 . The composite body of  claim 1 , wherein the bound mixture may further include any one or any combination of sodium bicarbonate, polymer, plaster, metal, ceramic, ash, and organic powders. 
     
     
         14 . A method of forming a composite body, comprising the steps of:
 printing a plurality of layers each including binder and sand into a 3D bound mixture;   infiltrating the bound mixture with a resin to strengthen the bound mixture; and   applying a coating to an outer surface of the bound mixture strengthened by the resin.   
     
     
         15 . The method forming the composite body of  claim 14 , wherein the coating has a first thickness less than a second thickness defined by the bound mixture, and wherein the coating infiltrates at least a portion of the bound mixture. 
     
     
         16 . The method forming the composite body of  claim 14 , further comprising:
 infiltrating the coating into at least a portion of the bound mixture.   
     
     
         17 . The method forming the composite body of  claim 14 , further comprising:
 using software to model the bound mixture into a predetermined shape.   
     
     
         18 . The method forming the composite body of  claim 17 , wherein the predetermined shape is a sacrificial tool. 
     
     
         19 . The method forming the composite body of  claim 14 , wherein either or both of inner and outer surfaces of the bound mixture is infiltrated with the resin. 
     
     
         20 . The method forming the composite body of  claim 14 , wherein the bound mixture defines pores into which the resin is infiltrated, the resin filling a plurality of pores of the bound mixture.