The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 27, 1999
Filed:
Sep. 26, 1996
Mehrdad Yasrebi, Clackamas, OR (US);
David Howard Sturgis, Boring, OR (US);
William Warren Kemp, Milwaukie, OR (US);
Mark Edwin Springgate, Portland, OR (US);
Douglas Gene Nikolas, Battleground, WA (US);
PCC Structurals, Inc., Portland, OR (US);
Abstract
Methods and compositions for forming shells for investment casting and methods for casting metal articles using the shells are described. One embodiment of the method comprises serially immersing a pattern in at least one, and perhaps several different slurries, each of which slurries comprises refractory material and from about 0 to about 30 volume percent inorganic binder. This forms a facecoat and plural refractory backup layers about the pattern, the facecoat and at least one backup layer defining a shell. The facecoat and/or the shell is then infiltrated with a binder. Infiltrating the shell with a binder is a key feature of the present invention. Infiltration refers to any process whereby a binder can be introduced into the facecoat and/or the subsequent layers built up about the shell. One method of infiltrating the facecoat and/or layers with binder comprises immersing the pattern having refractory material into a slurry comprising a binder, including inorganic binders, organic binders, and mixtures thereof. The pattern then is separated from the shell, forming a shell having an internal void in the shape of an article to be cast. Molten metal is then introduced into the void and allowed to solidify.