US 6,109,332 A · Ceramic mold finishing

Abstract

A technique for smoothing and otherwise changing the surfaces of porous bodies, such as ceramic molds, made using layer manufacturing processes, such as three dimensional printing processes. The surface finish of the mold can be smoothed by casting a slip of fine particles onto the surface to form a generally level, and preferably non-conformal, coating on the surfaces. In general, the fine particles of the slip are caused to be filtered out from the liquid, so that the fine particles come to rest at or near the surface of the body formed. They are typically, preferentially drawn toward concave regions of the surface, as compared to convex regions, thereby forming a non-conformal coating. Furthermore, other surface properties can be changed by tailoring the slip to produce those properties. The coating can be applied to external surfaces, and internal surfaces, such as would become the surface against which a molded part would be formed.

Claims14

Dependent claims

A process for fabricating a porous body comprising the steps of:

a. building up said body by creating successive layers of a powder material, each layer being on average at least three powder particles thick, whereby due to said layer buildup, a surface of said body having a first surface roughness resulting from concave regions that are adjacent to convex regions, with a porous region between said concave and convex regions, made up of an edge of one of said layers that is, on average at least three particles thick;
and
b. casting a slip of fine particles against the concave and convex regions of said surface of the body, whereby said fine particles are smaller, on average, than the powder particles, and are drawn preferentially toward said concave regions to a degree greater than toward said convex regions, so that the surface of said body is coated with a surface coating of said fine particles, such that the surface roughness is decreased from said first degree to a smoother, second degree of roughness.

Dependencies are inferred from the claim text.

Ceramic mold finishing

Life of this patent

Ceramic mold finishing

Life of this patent

Abstract

Claims14