Method for the rapid fabrication of mold inserts

Abstract

A method for the rapid fabrication of mold inserts for molds and molds c is disclosed; wherein high machinability rates and time and cost savings along with increased tool life and material savings are obtained through the use of blank die inserts formulated from material commonly used in the metal injection molding process of complex shaped parts. The method involves first the creation of cutting path programs developed from CAD files of the part; direct machining of the cavity and core inserts as described to predetermined sizes; processing the cavity and core inserts to convert the soft material—initially consisting of fine metal powders in a matrix of binder compounds—into a dense, fully hardenable material comparable to the material used in conventional toolmaking; and performing any necessary finishing and fitting operations to fit the resulting dies into a base that can be used as part of an injection molding tool.

We claim:  
     
         1 . A method of fabricating mold inserts comprising the steps of: 
 a-) creating a blank die block from a metal alloy material, consisting of fine metal powders bound together by any combination of appropriate binders that form a material compound commonly used in powder injection molding processes.    b-) applying a cutting path program developed from the CAD files or similar of the part application, and directly machining said die block by milling or related means corresponding cavity and core die inserts.    c-) processing said cavity and core inserts respectively to consolidate the fine metal powders including a means to remove said binder of said metal alloy material and forming a sintered metal core and/or cavity insert.    d-) finishing said sintered metal insert to fit into a mold base or master mold for molding of metal, ceramics, plastic, die casting and related processes.    
     
     
         2 . The method of  claim 1 , wherein the material used to produce the die blocks that result in cavity and core inserts are from the group of tool steels, carbon steels, stainless steels and other ferrous powders and alloys that can be processed to near full density and heat treated.  
     
     
         3 . The method of  claim 1 , wherein the material used to produce the die blocks that result in cavity and core inserts are form the group of any non-ferrous powder such as copper and bronze, that can be processed to near full density.  
     
     
         4 . A method for the fabrication of mold inserts comprising the following steps: 
 a-) creating a CAD or computer model of the tooling die inserts from a part configuration.    b-) scaling the said model to allow for shrinkage resulting from subsequent processing plus expected shrinkage for the tooling application.    c-) developing cutting path programs for CNC, milling or other related machining processes for the corresponding cavity and core die inserts.    d-) fabricating blank die blocks from a metal alloy material consisting of fine metal powders bound together by any combination of appropriate binders that form a material compound commonly used in powder injection molding processes.    e-) applying a cutting path program developed from the CAD files or similar of the part application, and directly machining said die block by milling or related means said cavity and core die inserts.    f-) processing said cavity and core inserts respectively to consolidate the fine metal powders including a means to remove said binder of said metal alloy material and forming a sintered metal core and/or cavity insert.    g-) finishing said sintered metal inserts by grinding, polishing, assembling of mold components and related activities to fit into a mold base or master mold for molding of metal, ceramics, plastic, die casting and/or related processes.    
     
     
         5 . the method of  claim 2 , wherein the machining step (e) includes the addition of ejector hole locations, coordinate reference points, water cooling channels and other features normally required in an injection molding or die casting tool.  
     
     
         6 . the method of  claim 2 , wherein the cooling channels are included in a component refered to as a yoke.