Process for additively manufacturing discrete gradient charges

Patent metadata

Field	Value
Publication number	US-11040924-B1
Application number	US-201815999998-A
Country	US
Kind code	B1
Filing date	Sep 17, 2018
Priority date	Sep 17, 2018
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A discrete gradient charge that has a discrete first hollow cylindrical layer of a solid first fuel, which is about 85% by weight fine aluminum powder having a median diameter of about 3.5 microns. There is a discrete second hollow cylindrical layer of a solid second fuel that is about 80% by weight coarse aluminum powder with a median diameter of about 31.0 microns. The fuels have a cured HTPB binder. A pellet of an explosive positioned within the first hollow cylindrical layer provides ignition. The fuel in the charge reacts with the surrounding air or with a hollow cylindrical oxidizer layer, or a combination thereof.

First claim

What is claimed is:

1. An additive manufacturing (AM) process for making a discrete gradient charge, said process comprising:
acoustically mixing components of a first fuel comprised of: a fine aluminum powder and a curable binder, therein forming a first paste that is about 85% solids by weight;
building by additive manufacturing a discrete first layer that has a hollow cylindrical form with a first diameter by extruding a circular coiled stream of the first paste with a series of continuous overlapping passes of the first paste until a desired height is attained;
allowing the series of continuous overlapping passes of the first paste to meld and cure into a solid discrete first layer of the first fuel; and building by additive manufacturing a discrete second layer that has a second hollow cylindrical form with a second diameter, which is greater than the first diameter, by extruding the second paste also as a circular coiled stream with a series of continuous overlapping passes of the second paste until the desired height is attained.

2. The AM process according to claim 1 , wherein the first paste is mixed by acoustically agitating the first fuel components at a frequency of about 60 Hz.

3. The AM process according to claim 1 , further comprising:
acoustically mixing second components of a second fuel comprised of: a coarse aluminum powder and the curable binder therein, therein forming a second paste that is about 80% solids by weight;
stream with a series of continuous overlapping passes of and
allowing the series of continuous overlapping passes of the second paste to meld and cure into a solid discrete second layer of the second fuel.

4. The AM process according to claim 3 , wherein the second paste is mixed by acoustically agitating the components of the second fuel at a frequency of about 60 Hz.

5. The AM process according to claim 1 , wherein a pellet of an explosive is positioned within the first diameter of the solid discrete first layer.

6. The AM process according to claim 3 , wherein a pellet of an explosive is positioned within the first diameter of the solid discrete first layer.

7. The AM process according to claim 1 , further comprising:
acoustically mixing oxidizer components comprised of: a powder of bismuth triiodate and the curable binder, therein forming an oxidizer paste that is about 92% solids by weight;
building by additive manufacturing a discrete over layer that has an outer hollow cylindrical form with a oxidizer diameter, which is greater than the first diameter, by extruding the oxidizer paste as a second circular coiled stream with a series of continuous overlapping passes of the oxidizer paste until the desired height is attained; and
allowing the series of continuous overlapping passes of the oxidizer paste to meld and cure into a solid discrete oxidizer layer.

8. The AM process according to claim 7 , wherein a pellet of an explosive is positioned within the first diameter of the solid discrete first layer.

9. The AM process according to claim 1 , wherein the fine aluminum power has a median spherical diameter of about 3.5 microns.

10. The AM process according to claim 3 , wherein the coarse aluminum power has a median spherical diameter of about 31.0 microns.

11. A discrete gradient charge, said charge comprising:
an inner discrete first hollow cylindrical layer of a solid first fuel that is comprised of about 85% by weight fine aluminum powder;
a second discrete hollow cylindrical layer of a solid second fuel that is comprised of about 80% by weight coarse aluminum powder;
a cured binder; and
a pellet of an explosive positioned within the first hollow cylindrical layer.

12. The AM process according to claim 11 , wherein the fine aluminum power has a median spherical diameter of about 3.5 microns.

13. The AM process according to claim 11 , wherein the coarse aluminum power has a median spherical diameter of about 31.0 microns.

14. The discrete gradient charge according to claim 11 , wherein said pellet is comprised of PBXN-5.

15. A discrete gradient charge, said charge comprising:
an inner discrete first hollow cylindrical layer of a solid first fuel that is comprised of about 85% by weight of a fine aluminum powder;
an outer discrete second hollow cylindrical layer of a solid oxidizer that is that is comprised of about 92% by weight bismuth triiodate;
a cured binder; and
a pellet of an explosive positioned within the first hollow cylindrical layer.

16. The discrete gradient charge according to claim 15 , wherein said explosive is PBXN-5.

17. An additive manufacturing (AM) process for making a gradient discrete charge, said process comprised of the steps of:
combining components comprised of: a fine aluminum powder with a curable binder, therein forming a first paste which is a first fuel;
building by additive manufacturing a discrete first layer creating a hollow cylindrical form with a first diameter, by extruding a circular coiled stream of the first paste with a series of continuous overlapping passes until a desired height is attained;
allowing the series of continuous overlapping passes to meld and cure into a solid discrete first layer of the first fuel;
combining components comprised of: a coarse aluminum powder with a suitable curable binder, therein forming a second paste which is a second fuel;
building by additive manufacturing a second discrete layer that has a second hollow cylindrical form with a second diameter by extruding a second circular coiled stream of the second paste with a second series of continuous overlapping passes until the desired height is attained; and
allowing the second series of continuous overlapping passes to meld and cure into a solid discrete second layer of the second fuel.

18. An additive manufacturing process for making a gradient discrete charge, said process comprised of the steps of:
combining components comprised of: a fine aluminum powder with a curable binder, therein forming a first paste which is a first fuel;
building by additive manufacturing a discrete first layer creating an inner hollow cylindrical form with a first diameter, by extruding a circular coiled stream of the first paste with a series of continuous overlapping passes until a desired height is attained;
allowing the series of continuous overlapping passes to meld and cure into a solid discrete first layer of the first fuel;
combining oxidizer components comprised of: a powder of an oxidizer and a binder that be cured, therein forming an oxidizer paste;
building by additive manufacturing a discrete oxidizer layer that has an outer hollow cylindrical form with an oxidizer diameter, which is greater than the first diameter, by extruding a second circular coiled stream of the oxidizer paste with a second series of continuous overlapping passes until the desired height is attained; and
allowing the second series of continuous overlapping passes to meld and cure into a solid discreet oxidizer layer.

19. The discrete gradient charge according to claim 16 , wherein the median diameter of the fine aluminum is about 3.5 microns, wherein about 90% is less than or equal to 7.5 microns, and only about 10% is less than or equal to 1.8 microns.

20. The discrete gradient charge according to claim 16 , wherein the median diameter of the coarse aluminum is about 31.0 microns, wherein about 90% is less than or equal to 58.0 microns, and only about 10% is less than or equal to about 15.0 microns.

Assignees

• Castellanos Jorge
• Stamatis Demitrios
• Emery Samuel B
• Zamor David O
• Gay Meagan E
• Mcdaniel Jr George W
• Riggins Austin W
• Us Navy

Inventors

• Castellanos Jorge
• Stamatis Demitrios
• Emery Samuel B
• Zamor David O
• Gay Meagan E
• Mcdaniel Jr George W
• Riggins Austin W

Classifications

• C06B45/14

  a layer or zone containing an inorganic explosive or an inorganic explosive or an inorganic thermic component · CPC title

• C06B21/0033 Primary

  Shaping the mixture · CPC title

• C06B45/00 Primary

  Compositions or products which are defined by structure or arrangement of component of product (explosive charges of particular form or shape F42B1/00, F42B3/00) · CPC title