Method of making a metal primer insert by injection molding

Abstract

The present invention provides a method of making a substantially cylindrical insert by metal injection molding by providing a primer insert injection mold to form a substantially cylindrical metal primer insert, injection molding the metal injection molding feedstock into the primer insert injection mold to form a first substantially cylindrical metal primer insert having a first size; debinding the first substantially cylindrical metal primer insert to remove the first binding agent; and sintering the first substantially cylindrical metal primer insert to remove the second binding agent and form the substantially cylindrical metal primer insert having a second size.

What is claimed is: 
     
         1 . A method of making a substantially cylindrical insert by metal injection molding comprising the steps of:
 providing a primer insert injection mold to form a substantially cylindrical metal primer insert, wherein the primer insert mold comprises a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash aperture positioned in the primer recess to extend through the bottom surface, and a flange that extends circumferentially about an outer edge of the top surface, wherein the flange is adapted to receive a polymer overmolding that covers an circumferential surface and the primer flash hole aperture to form a primer flash hole;   providing a metal injection molding feedstock comprising a powdered metal and a first binding agent and a second binding agent;   injection molding the metal injection molding feedstock into the primer insert injection mold to form a first substantially cylindrical metal primer insert having a first size;   debinding the first substantially cylindrical metal primer insert to remove the first binding agent; and   sintering the first substantially cylindrical metal primer insert to remove the second binding agent and form the substantially cylindrical metal primer insert having a second size.   
     
     
         2 . The method of  claim 1 , wherein the powdered metal comprises stainless steel, brass, ceramic alloys. 
     
     
         3 . The method of  claim 1 , wherein the powdered metal comprises 102, 174, 201, 202, 300, 302, 303, 304, 308, 309, 316, 316L, 316Ti, 321, 405, 408, 409, 410, 415, 416, 416R, 420, 430, 439, 440, 446 or 601-665 grade stainless steel or Ti6Al4V. 
     
     
         4 . The method of  claim 1 , wherein the second size is about 5 percent to about 30 percent smaller than the first size or the second size is about 10 percent to about 20 percent smaller than the first size. 
     
     
         5 . The method of  claim 1 , wherein the second size is about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 percent smaller than the first size. 
     
     
         6 . The method of  claim 1 , wherein the substantially cylindrical insert further comprises a flash hole groove that extends circumferentially about the primer flash aperture on the top surface in the primer recess. 
     
     
         7 . The method of  claim 1 , wherein the bottom surface comprises a circumferential groove. 
     
     
         8 . The method of  claim 1 , wherein the flange is a combination of a circumferential groove and one or more notches. 
     
     
         9 . The method of  claim 1 , wherein the flange comprises one or more notches or scallops positioned circumferential. 
     
     
         10 . The method of  claim 1 , wherein the flange comprises 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 notches or scallops positioned circumferential. 
     
     
         11 . The method of  claim 1 , wherein the powdered metal comprises 2-16% Ni; 10-20% Cr; 0-5% Mo; 0-0.6% C; 0-6.0% Cu; 0-0.5% Nb+Ta; 0-4.0% Mn; 0-2.0% Si and the balance Fe; or the powdered metal comprises 2-6% Ni; 13.5-19.5% Cr; 0-0.10% C; 1-7.0% Cu; 0.05-0.65% Nb+Ta; 0-3.0% Mn; 0-3.0% Si and the balance Fe; or the powdered metal comprises 3-5% Ni; 15.5-17.5% Cr; 0-0.07% C; 3-5.0% Cu; 0.15-0.45% Nb+Ta; 0-1.0% Mn; 0-1.0% Si and the balance Fe; or the powdered metal comprises 10-14% Ni; 16-18% Cr; 2-3% Mo; 0-0.03% C; 0-2% Mn; 0-1% Si and the balance Fe; or the powdered metal comprises 12-14% Cr; 0.15-0.4% C; 0-1% Mn; 0-1% Si and the balance Fe; or the powdered metal comprises 16-18% Cr; 0-0.05% C; 0-1% Mn; 0-1% Si and the balance Fe; or the powdered metal comprises 3-12% aluminum, 2-8% vanadium, 0.1-0.75% iron, 0.1-0.5% oxygen, and the remainder titanium; or the powdered metal comprises about 6% aluminum, about 4% vanadium, about 0.25% iron, about 0.2% oxygen, and the remainder titanium. 
     
     
         12 . A method of making a substantially cylindrical insert by metal injection molding comprising the steps of:
 providing a primer insert injection mold to form a substantially cylindrical primer insert, wherein the primer insert mold comprises a top surface opposite a bottom surface and a substantially cylindrical coupling element that extends from the bottom surface, a primer recess in the top surface that extends toward the bottom surface, a primer flash aperture positioned in the primer recess to extend through the bottom surface, a flange that extends circumferentially about an outer edge of the top surface, wherein the flange is adapted to receive a polymer overmolding that covers an circumferential surface and the primer flash hole aperture to form a primer flash hole, and a flash hole groove that extends circumferentially about the primer flash aperture on the top surface in the primer recess;   providing an injection molding feedstock comprising a powder and a first binding agent and a second binding agent, wherein the powder comprises a stainless steel powder, brass powder, alloy powder, ceramic alloys powder or a combination thereof;   injection molding the injection molding feedstock into the primer insert injection mold to form a first substantially cylindrical primer insert having a first size;   debinding the first substantially cylindrical primer insert to remove the first binding agent; and   sintering the first substantially cylindrical metal primer insert to remove the second binding agent and form the substantially cylindrical primer insert having a second size, wherein the second size is about 10 percent to about 25 percent smaller than the first size.   
     
     
         13 . The substantially cylindrical metal primer insert made by the method of  claim 12 .