Process for strengthening porous 3D printed objects
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 3D printed composite body, comprising:
a bound mixture including a binder and a plurality of particles including bound and unbound particles, the bound mixture being porous;
a resin infiltrating the bound mixture to strengthen the bound mixture; and
a coating applied to an exterior surface of the bound mixture strengthened by the resin,
wherein the coating infiltrates at least a portion of the bound mixture.
2. The composite body of claim 1 , wherein the coating includes a filler being one of ceramic powder and polymer powder.
3. The composite body of claim 1 , wherein the coating has a first thickness less than a second thickness defined by the bound mixture.
4. The composite body of claim 1 , wherein the coating is applied to the exterior 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.
5. The composite body of claim 1 , wherein the binder is one part of a two-part curable resin.
6. The composite body of claim 1 , wherein the plurality of particles are made of any one or any combination of a sand, sodium bicarbonate, polymer, plaster, metal, ceramic, ash, and organic powders.
7. The composite body of claim 1 , wherein the resin is applied to the bound mixture from a plurality of directions to define a part line.
8. The composite body of claim 1 , wherein the porous bound mixture defines a gradient porosity.
9. The composite body of claim 1 , wherein an interior surface of the bound mixture is less porous than the exterior surface of the bound mixture.
10. 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.
11. The composite body of claim 1 , wherein at least a portion of the unbound particles is not infiltrated by the resin.
12. The composite body of claim 1 , wherein at least a portion of the bound mixture is not infiltrated by the resin.
13. The composite body of claim 1 , wherein at least a portion of the bound mixture is not infiltrated by the coating.
14. A method of forming a 3D printed composite body, comprising the steps of:
combining a plurality of particles including bound and unbound particles with a binder to form a porous bound mixture;
infiltrating the bound mixture with a resin to strengthen the bound mixture; and
applying a coating to the exterior surface of the bound mixture,
the coating having 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.
15. The method of claim 14 , further comprising the step of:
removing at least a portion of the bound mixture.
16. The method of claim 14 , wherein the combining step includes forming the bound mixture around the unbound particles.
17. The method of claim 16 , further comprising the step of:
removing the unbound particles and the bound mixture.
18. The method of claim 14 , wherein the coating is a metal plating.
19. The method of claim 18 , further comprising the step of:
removing at least a portion of the bound mixture from the coating.