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:
Oct. 09, 1990
Filed:
Jun. 30, 1989
Robert E Downing, Toledo, OH (US);
Farley, Inc., Chicago, IL (US);
Abstract
A method for producing high pressure die castings with undercut regions comprises forming an expendable coated core of specific composition, placing it in the die in a die casting machine, injecting molten metal into the die to form the casting and separating the casting from the die and the core from the casting. The composition of the expendable coated core comprises a base sand core held together by a resin binder; a first, bottom, hard refractory coating comprising fused silica and a refractory binder containing at least two of the following additives: a suspension agent, a dispersant, a wetting agent, and an anti-skinning agent; and a second, top, soft, or release coating containing a release material selected from the group consisting of anhydrous powdered aluminum, graphite, talc, titanium dioxide and zircon, and a resinous binder containing at least two different compounds selected from the group of additives consisting of a suspension agent, a dispersant, and an anti-settling agent.