Method of making polymer ammunition having a metal injection molded primer insert

• US 10,145,662 B2
• Filed: 06/24/2015
• Issued: 12/04/2018
• Est. Priority Date: 11/10/2010
• Status: Active Grant

• Current Assignee: Velocity Holdings LLC (Centerpoint Energy Incorporated)
• Original Assignee: Velocity Holdings LLC (Centerpoint Energy Incorporated)
• Inventors: Burrow, Lonnie
• Primary Examiner(s): Weber, Jonathan C
• Application Number:
  US14/748,984
• Publication Number:
  US 20160003596A1
• Time in Patent Office: 1,259 Days
• Field of Search: 102466, 102467, 102516, 102517, 102465
• CPC Class Codes: B22F 1/108 Mixtures obtained by warm mixing
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 3/004 Filling molds with powder feeding material to presses in general B30B15/302
• CPC Class Codes: B22F 3/10 Sintering only
• CPC Class Codes: B22F 3/1021 Removal of binder or filler removal of binder from ceramics C04B35/638
• CPC Class Codes: B22F 3/1025 not by heating only
• CPC Class Codes: B22F 3/225 by injection molding
• CPC Class Codes: B22F 5/00 Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
• CPC Class Codes: B22F 5/06 of threaded articles, e.g. nuts
• CPC Class Codes: B22F 9/04 starting from solid material, e.g. by crushing, grinding or milling C22C1/1084 takes precedence; crushing, grinding or milling, in general, see the relevant subclasses, e.g. B02C
• CPC Class Codes: C04B 35/64 Burning or sintering processes C04B33/32 takes precedence ; powder metallurgy B22F
• CPC Class Codes: C22C 1/0458 Alloys based on titanium, zirconium or hafnium
• CPC Class Codes: C22C 14/00 Alloys based on titanium
• CPC Class Codes: C22C 33/0257 characterised by the range of the alloying elements
• CPC Class Codes: C22C 33/0285 with Cr, Co, or Ni having a minimum content higher than 5%
• CPC Class Codes: C22C 38/02 containing silicon
• CPC Class Codes: C22C 38/04 containing manganese
• CPC Class Codes: C22C 38/18 containing chromium
• CPC Class Codes: C22C 38/42 with copper
• CPC Class Codes: C22C 38/44 with molybdenum or tungsten
• CPC Class Codes: C22C 38/48 : with niobium or tantalum
• CPC Class Codes: C22C 38/58 : with more than 1.5% by weight of manganese
• CPC Class Codes: F42B 33/00 : Manufacture of ammunition; Dismantling of ammunition; Apparatus therefor F42B5/188 takes precedence; manufacturing processes for hollow charges F42B1/036; manufacture of blasting cartridge initiators F42B3/195
• CPC Class Codes: F42B 33/001 : Devices or processes for assembling ammunition, cartridges or cartridge elements from parts
• CPC Class Codes: F42B 33/02 : Filling cartridges, missiles, or fuzes; Inserting propellant or explosive charges F42B33/004 takes precedence
• CPC Class Codes: F42B 33/04 : Fitting or extracting primers in or from fuzes or charges F42B33/004 takes precedence
• CPC Class Codes: F42B 5/02 : Cartridges, i.e. cases with charge and missile
• CPC Class Codes: F42B 5/025 : characterised by the dimension of the case or the missile
• CPC Class Codes: F42B 5/30 : of plastics , i.e. the cartridge-case tube is of plastics
• CPC Class Codes: F42B 5/307 : formed by assembling several elements
• CPC Class Codes: F42B 5/313 : all elements made of plastics
• CPC Class Codes: F42C 19/0807 : characterised by the particular configuration of the transmission channels from the priming energy source to the charge to be ignited, e.g. multiple channels, nozzles, diaphragms or filters
• CPC Class Codes: F42C 19/0823 : Primers or igniters for the initiation or the propellant charge in a cartridged ammunition primers for caseless ammunition F42C19/085
• CPC Class Codes: F42C 19/083 : characterised by the shape and configuration of the base element embedded in the cartridge bottom, e.g. the housing for the squib or percussion cap

Abstract

The present invention provides a method of making polymer ammunition having a metal injection molded primer insert.

Claims

1. A method of making a polymer ammunition having an injection molded primer insert comprising by the steps of:

forming a substantially cylindrical primer insert by injection molding from a primer insert injection mold, wherein the substantially cylindrical primer insert 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 primer flash aperture groove positioned in the primer recess around the primer flash aperture, a primer flash aperture groove positioned in the primer recess around the primer flash aperture, and a flange that extends circumferentially about an outer edge of the top surface;

providing a first polymer composition for molding a polymer ammunition cartridge;

molding from the first polymer composition a substantially cylindrical polymeric middle body having the substantially cylindrical primer insert at a first end and a substantially cylindrical polymeric coupling region at a second end, wherein the first polymer composition extends over an outer surface of the substantially cylindrical primer insert to the flange and extends over an interior surface of the substantially cylindrical coupling region into the primer flash hole aperture and into the primer flash aperture groove, wherein the first polymer composition is overmolded into the primer flash hole aperture to form a flash hole the primer flash hole aperture;

forming a substantially cylindrical polymeric bullet-end component from a second polymer composition comprising a bullet aperture opposite a polymeric bullet-end coupling that mates to the substantially cylindrical coupling region;

coupling the substantially cylindrical coupling region to the polymeric bullet-end coupling to form a propellant chamber that extends from the primer flash hole aperture to the bullet aperture;

inserting a primer diffuser into the primer recess, wherein the primer diffuser comprises a diffuser aperture that aligns with the primer flash hole aperture and the primer flash hole;

inserting a primer into the primer recess in contact with the primer diffuser, wherein the primer is in operably communication with the propellant chamber through the primer flash hole aperture;

at least partially filling the propellant chamber with a propellant; and

frictionally fitting a projectile in the bullet-end aperture, wherein the propellant chamber is enclosed at one end by the primer and the projectile at the other end.

2. The method of claim 1, wherein the first polymer composition is the same as the second polymer composition.

3. The method of claim 1, wherein the first polymer composition is a ductile polymer.

4. The method of claim 1, wherein the first polymer composition, the second polymer composition or both comprise a nylon polymer.

5. The method of claim 1, wherein the first polymer composition, the second polymer composition or both comprise a fiber-reinforced polymeric composite.

6. The method of claim 1, wherein the first polymer composition, the second polymer composition or both comprise between about 10 and about 70 wt % glass fiber fillers, mineral fillers, or mixtures thereof.

7. The method of claim 1, wherein the bullet aperture comprises one or more cannelures formed on an inner circumferential surface of the bullet aperture.

8. The method of claim 1, wherein the substantially cylindrical coupling region and the polymeric bullet-end coupling are welded or bonded together.

9. The method of claim 1, wherein the first polymer composition, the second polymer composition or both comprise polyurethane prepolymer, cellulose, fluoro-polymer, ethylene inter-polymer alloy elastomer, ethylene vinyl acetate, nylon, polyether imide, polyester elastomer, polyester sulfone, polyphenyl amide, polypropylene, polyvinylidene fluoride or thermoset polyurea elastomer, acrylics, homopolymers, acetates, copolymers, acrylonitrile-butadinen-styrene, thermoplastic fluoro polymers, inomers, polyamides, polyamide-imides, polyacrylates, polyatherketones, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene, terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, polypropylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene, ether blends, styrene maleic anhydrides, polycarbonates, allyls, aminos, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, polyphenylsulfones, copolymers of polyphenylsulfones with polyethersulfones or polysulfones, copolymers of poly-phenylsulfones with siloxanes, blends of polyphenylsulfones with polysiloxanes, poly(etherimide-siloxane) copolymers, blends of polyetherimides and polysiloxanes, and blends of polyetherimides and poly(etherimide-siloxane) copolymers.

10. The method of claim 1, further comprising a neck positioned between the bullet aperture and the polymeric bullet-end coupling.

11. The method of claim 10, further comprising one or more internal structures in the neck to support a projectile.

12. The method of claim 1, wherein the bullet aperture comprises one, two, three, or more annular rings that mate with one, two, three, or more corresponding annular grooves positioned on the projectile.

13. The method of claim 1, wherein the injection molded primer insert 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.

14. The method of claim 1, wherein the injection molded primer insert 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.

15. The method of claim 1, wherein the injection molded primer insert 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.

16. The method of claim 1, wherein the injection molded primer insert comprises 10-14% Ni;

16-18% Cr;

2-3% Mo;

0-0.03% C;

0-2% Mn;

0-1% Si and the balance Fe.

17. The method of claim 1, wherein the injection molded primer insert comprises 12-14% Cr;

0.15-0.4% C;

0-1% Mn;

0-1% Si and the balance Fe.

18. The method of claim 1, wherein the injection molded primer insert comprises 16-18% Cr;

0-0.05% C;

0-1% Mn;

0-1% Si and the balance Fe.

19. The method of claim 1, wherein the injection molded primer insert comprises 3-12% aluminum, 2-8% vanadium, 0.1-0.75% iron, 0.1-0.5% oxygen, and the remainder titanium.

20. The method of claim 1, wherein the injection molded primer insert comprises about 6% aluminum, about 4% vanadium, about 0.25% iron, about 0.2% oxygen, and the remainder titanium.

21. A method of making a polymer ammunition having an injection molded primer insert comprising by the steps of:

forming a substantially cylindrical primer insert by injection molding from a primer insert injection mold, wherein the substantially cylindrical primer insert 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 primer flash aperture groove positioned in the primer recess around the primer flash aperture, and a flange that extends circumferentially about an outer edge of the top surface;

providing a first polymer composition for molding a polymer ammunition cartridge;

molding from the first polymer composition to form over the substantially cylindrical primer insert to form a substantially cylindrical polymeric middle body having the overmolded substantially cylindrical primer insert at a first end and a substantially cylindrical polymeric coupling region at a second end, wherein the first polymer composition extends over an outer surface of the substantially cylindrical primer insert to the flange and extends over an interior surface of the substantially cylindrical coupling region into the primer flash hole aperture and into the primer flash aperture groove to form a flash hole, wherein the first polymer composition extends from the substantially cylindrical polymeric coupling region to the primer flash aperture groove to form a flash hole;

forming a substantially cylindrical polymeric bullet-end component from a second polymer composition comprising a bullet aperture opposite a polymeric bullet-end coupling that mates to the substantially cylindrical coupling region, and a neck positioned between the bullet aperture and the polymeric bullet-end coupling;

coupling the substantially cylindrical coupling region to the polymeric bullet-end coupling to form a propellant chamber that extends from the primer flash hole aperture to the bullet aperture;

inserting a primer diffuser into the primer recess, wherein the primer diffuser comprises a diffuser aperture that aligns with the primer flash hole aperture and the primer flash hole;

inserting a primer into the primer recess, wherein the primer is in operably communication with the propellant chamber through the primer flash hole aperture;

at least partially filling the propellant chamber with a propellant; and

frictionally fitting a projectile in the bullet-end aperture, wherein the propellant chamber is enclosed at one end by the primer and the projectile at the other end.