Optimized recursive foundry tooling fabrication method

Abstract

A method for producing a pattern for making a cast part is described which comprises the steps of defining the structure of the part in terms of computer aided design system data, selecting a parting surface for the part to be cast; defining core requirements for the part by sweeping each positive feature of the part to the parting surface, subtracting the part from the projection, adding any remaining volume to the core, sweeping negative features away from the parting surface to the top or bottom of the mold and subtracting the negative features from the projection and intersecting the remainder of the part and adding any remaining volume to the core; repetitively generating alternative parting surfaces for the part and defining the corresponding core requirements whereby an optimum parting surface is defined for which the quantity and complexity of the corresponding core requirements are minimized, constructing core prints for each core requirement; constructing a pattern by adding the core prints to the part; and defining draft for the pattern surfaces perpendicular to the optimum parting surface.

We claim: 
     
       1. A method for producing a mold pattern for making a cast part, comprising the steps of: (a) defining the structure of a part to be cast in terms of computer aided design system data;   (b) selecting a parting surface for said part defined by said computer aided design system data, said parting surface defining a selected orientation of said part within a mold;   (c) defining core requirements for said part to be cast by first sweeping each positive feature of the part to said parting surface, subtracting said part from the projection on said parting surface and adding any remaining volume to the core, and then by sweeping negative features of said part away from said parting surface to the top or bottom of said mold, subtracting said negative features from said projection and intersecting the remainder of said part and adding any remaining volume to said core;   (d) successively selecting alternative parting surfaces for said part and defining the corresponding core requirements whereby an optimum parting surface having minimum core requirements is defined, (e) molding core pieces defined by said core requirements defined at said optimum parting surface for said part to be cast; and   (f) assembling said core pieces in a mold box to define the mold pattern for said part.   
     
     
       2. A method for producing a mold pattern for making a cast part, comprising the steps of: (a) defining the structure of a part to be cast in terms of computer aided design system data;   (b) selecting a parting surface for said part defined by said computer aided design system data, said parting surface defining a selected orientation of said part within a mold;   (c) defining first core requirements for said part by first sweeping each positive feature of said part to said parting surface, subtracting said part from said projection on said parting surface and adding any remaining volume to the core, and then sweeping negative features away from said parting surface to the top or bottom of said mold, subtracting the negative features from said projection and intersecting the remainder of said part and adding any remaining volume to the core;   (d) successively selecting alternative parting surfaces for said part and defining the corresponding core requirements whereby an optimum parting surface having minimum core requirements is defined;   (e) defining second core requirements for each first core requirement defined for said part for said optimum parting surface by repeating step (c) for each said first core requirement defined at said optimum parting surface;   (f) molding core pieces defined by said first and second core requirements defined at said optimum parting surface; and   (g) assembling said core pieces in a mold box to define the mold pattern for said part.