Aggregate-based mandrels for composite part production and composite part production methods

Abstract

A method for forming a composite structure, using a mandrel that is later removed from the composite structure, involves production of a mandrel by depositing a particulate mixture, including an aggregate and a binder, into a mold and removing the mandrel from the mold. The mandrel may be treated while still in the mold by heating, curing with an agent, microwave energy, or by some combination thereof. Once finished, the mandrel can be used in manufacturing polymer and/or composite components. The mandrel can also be include materials that can be easily removed from the finished composite structure by water, shakeout, chemically dissolving, or by some combination thereof.

1 . A method for manufacturing an article, comprising:
 preparing a non-fluid mixture comprising an aggregate material and a binder material;   fluidizing the mixture by exposing the mixture to a stress;   directing the fluidized mixture into a mold form to form a green mandrel;   hardening the green mandrel to form a mandrel; and   forming a composite material on the mandrel to produce the article.   
   
   
       2 . The method of  claim 1 , wherein the mixture is fluidized by entraining the mixture in a pressurized fluid medium, and the mixture is directed into the mold by propelling the fluid medium and mixture into the mold, wherein the fluid medium is able to escape from the mold and the non-fluid mixture remains in the mold. 
   
   
       3 . The method of  claim 1 , further comprising compressing the mixture in the mold before hardening the green mandrel. 
   
   
       4 . The method of  claim 1 , wherein the binder material comprises a water-soluble binder. 
   
   
       5 . The method of  claim 4 , further comprising:
 solubilizing the water-soluble binder by application of water thereto, in order to remove the mandrel from the article.   
   
   
       6 . The method of  claim 1 , wherein the binder material comprises an organic binder material and an inorganic binder material. 
   
   
       7 . The method of  claim 1 , wherein the binder material comprises polyvinylpyrollidone and sodium silicate. 
   
   
       8 . The method of  claim 7 , wherein the binder material comprises from about 1% to about 10% polyvinylpyrollidone and from about 1% to about 30% sodium silicate. 
   
   
       9 . The method of  claim 1 , wherein the green mandrel is hardened by activating the binder material to partially harden the green mandrel to form a partially-hardened mandrel, removing the partially-hardened mandrel from the mold, and completing the hardening process after removal. 
   
   
       10 . The method of  claim 1 , wherein hardening the green mandrel comprises drying the green mandrel. 
   
   
       11 . The method of  claim 1 , further comprising:
 curing the composite material by exposing the composite material to an energy source, to form the article.   
   
   
       12 . The method of  claim 11 , wherein the composite material is cured by a technique selected from the group consisting of: application of heat, application of pressure, application of light or other electromagnetic wave, chemical reaction, or any combination of said techniques. 
   
   
       13 . A mixture for use in manufacturing a mandrel, comprising:
 an organic binder material;   an inorganic binder material; and   an aggregate material.   
   
   
       14 . The mixture of  claim 13 , wherein at least one of the organic binder material and the inorganic binder material is water soluble. 
   
   
       15 . The mixture of  claim 13 , wherein the organic binder material comprises polyvinylpyrollidone and the inorganic binder material comprises sodium silicate. 
   
   
       16 . The mixture of  claim 15 , wherein the mixture comprises from about 1% to about 10% polyvinylpyrollidone and from about 1% to about 30% sodium silicate. 
   
   
       17 . The mixture of  claim 13 , further comprising at least one additive selected from the group consisting of: anhydrous salts, solvents, alkaline hydroxides, surfactants, humidity resistant additives, collapsibility enhancers, preservatives, dyes, bulking agents, hot strength additives, flow enhancers, and refractory coatings 
   
   
       18 . The mixture of  claim 13 , wherein at least one of the organic binder and the inorganic binder is microwave-curable. 
   
   
       19 . A method for manufacturing an article, comprising:
 preparing a non-fluid mixture comprising an aggregate material and a binder material;   fluidizing the mixture by exposing the mixture to a stress;   directing the fluidized mixture into a mold form to form a green mandrel;   hardening the green mandrel to form a mandrel; and   forming a polymer material on the mandrel to produce the article.   
   
   
       20 . The method of  claim 19 , wherein the mixture is fluidized by entraining the mixture in a pressurized fluid medium, and the mixture is directed into the mold by propelling the fluid medium and mixture into the mold, wherein the fluid medium is able to escape from the mold and the non-fluid mixture remains in the mold. 
   
   
       21 . The method of  claim 19 , further comprising compressing the mixture in the mold before hardening the green mandrel. 
   
   
       22 . The method of  claim 19 , wherein the binder material comprises a water-soluble binder, further comprising:
 solubilizing the water-soluble binder by application of water thereto, in order to remove the mandrel from the article.   
   
   
       23 . The method of  claim 19 , wherein the binder material comprises an organic binder material and an inorganic binder material. 
   
   
       24 . The method of  claim 19 , wherein the binder material comprises polyvinylpyrollidone and sodium silicate. 
   
   
       25 . The method of  claim 24 , wherein the binder material comprises from about 1% to about 10% polyvinylpyrollidone and from about 1% to about 30% sodium silicate. 
   
   
       26 . The method of  claim 19 , wherein the green mandrel is hardened by activating the binder material to partially harden the green mandrel to form a partially-hardened mandrel, removing the partially-hardened mandrel from the mold, and completing the hardening process after removal. 
   
   
       27 . The method of  claim 1 , wherein the article is a composite article, the method further comprising:
 forming a second material on the mandrel along with the polymer material to produce the composite article.   
   
   
       28 . The method of  claim 1 , further comprising:
 curing the polymer material by exposing the polymer material to an energy source, to form the article.