Method and apparatus for fabricating ceramic and metal components via additive manufacturing with uniform layered radiation drying
A freeform extrusion fabrication process for producing three-dimensional ceramic, metal and functionally gradient composite objects, including the steps of filling a plurality of paste sources with a respective plurality of aqueous paste compositions, operationally connecting respective syringes containing respective aqueous paste compositions to a mixing chamber, moving a first aqueous paste composition from a first respective paste source into the mixing chamber, moving a second aqueous paste composition from a second respective paste source into the mixing chamber, mixing the first and second aqueous paste compositions to define a first admixture having a first admixture composition, extruding the first admixture onto a surface to define an extruded layer having a first admixture composition, surrounding the sides of the extruded layer with an oil bath, radiatively drying the extruded layer.
1. A multilayered extrusion fabrication process for producing three-dimensional ceramic and metal objects, comprising:
a) preparing an aqueous paste;
b) extruding the aqueous paste onto a target surface in an oil tank to define an extruded layer having a top surface and at least one side surface;
c) filling the oil tank with sufficient oil to submerge the at least one side surface of the extruded layer in oil;
d) uniformly drying the extruded layer with an application of thermal energy through the top surface remove moisture contained therein; and
e) repeating steps b) through d) to define a green body made of a plurality of stacked, dried layers.
2. A multilayered extrusion fabrication process for producing three-dimensional compositionally gradient ceramic and metal objects, comprising:
a) preparing an aqueous paste, wherein the aqueous paste has a first composition;
b) extruding the aqueous paste onto a target surface in a liquid tank to define an extruded layer having a top surface and at least one side surface;
c) filling the liquid tank with sufficient oil to cover the at least one side surface of the extruded layer in liquid while leaving the top surface liquid-free;
d) heating the extruded layer to remove moisture through the top surface to yield a dried layer;
e) changing the composition of the aqueous paste to a second composition; and
f) repeating steps b) through e) to define a green body made of a plurality of stacked dried layers.
3. The process of claim 2 , wherein steps b) and e) occur simultaneously.
4. The process of claim 2 and further comprising:
g) draining liquid from the liquid tank; and
h) drying the green body to remove residual moisture.
5. The process of claim 2 wherein the second composition is different from the first composition.
6. The process of claim 2 wherein the green body is less than four volume percent binder.
7. The process of claim 2 wherein the green body is less than one volume percent binder.