Method of forming pre-defined recess in cured or cast explosive composition

Patent metadata

Field	Value
Publication number	US-11766809-B2
Application number	US-201916977969-A
Country	US
Kind code	B2
Filing date	Mar 1, 2019
Priority date	Mar 5, 2018
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

The invention relates to a process for forming a pre-defined recess in a cured or cast explosive composition comprising the steps of:i) providing a female mould,ii) providing a male former, and locating said male former proximate to the female mould to create a gap between said male former and female mould,iii) forming an admixture of a curable/castable explosive composition,charging the gap with the admixture of explosive composition, causing the cure or cast of said curable/castable explosive composition,removing the male former to furnish a cured or cast explosive composition with a pre-defined recess.

First claim

The invention claimed is:

1. A process for forming a recess in a cured or cast explosive composition, the process comprising:
providing a female mould;
providing a male former having an outer surface and an inner surface, and locating said male former proximate to the female mould to create a gap between said male former and female mould;
forming an admixture of a curable/castable explosive composition;
charging the gap with the admixture of explosive composition;
causing the cure or cast of said curable/castable explosive composition; and
removing the male former to furnish a cured or cast explosive composition with a recess, the recess being in a location occupied by at least a portion of the male former prior to the removal of the male former;
wherein the male former comprises at least one fluid vent that extends between the outer and inner surfaces of the male former; and
wherein a seal of the at least one fluid vent comprises a removable plug that is removable from the vent.

2. The process according to claim 1 , wherein the male former comprises an outer surface, which contacts said curable/castable explosive composition, wherein said outer surface comprises a release agent coated thereon.

3. The process according to claim 1 , wherein the at least one fluid vent is capable of transfer of a fluid through the male former, said fluid causing ejection of the male former from the cured or cast explosive composition.

4. The process according to claim 3 , wherein the at least one fluid vent is sealed by the removable plug, during the charging.

5. The process according to claim 4 , wherein the male former comprises an outer surface, and wherein the removable plug is flush fitting to the outer surface of the male former, and wherein the removable plug is removed from the vent during the transfer of the fluid through the male former.

6. The process according to claim 1 , the process further comprising applying resonant acoustic stimulus to the female mould and/or male former.

7. The process according to claim 1 , wherein the female mould is a payload cavity of a munition, wherein said curable/castable explosive composition comprises an explosive material, a polymerisable binder, and a cross linking reagent.

8. The process according to claim 7 , wherein the polymerisable binder is selected, such that it will form with the cross linking reagent a polyurethane, a cellulosic material, cellulose acetate, a polyester, a polybutadiene, a polyethylene, a polyisobutylene, PVA, chlorinated rubber, an epoxy resin, a two-pack polyurethane system, an alkyd/melanine, a vinyl resin, an alkyd, a thermoplastic elastomer, a butadiene-styrene block copolymer, polyNIMMO, polyGLYN, GAP, and a blend, copolymer and/or combination thereof.

9. The process according to claim 7 , wherein the explosive material is selected from RDX, HMX, FOX-7, TATND, HNS, TATB, NTO, HNIW, GUDN, picrite, an aromatic nitramine, tetryl, ethylene dinitramine, nitroglycerine, butane triol trinitrate, pentaerythritol tetranitrate, DNAN trinitrotoluene, an inorganic oxidiser, ammonium nitrate, ADN, ammonium perchlorate, an energetic alkali metal salt, an energetic alkaline earth metal salt, and combinations thereof.

10. The process according to claim 1 , wherein locating said male former proximate to the female mould includes retaining the male former at a location proximate to the female mould, and wherein the process further comprises:
retaining the location of the male former while (i) the gap is being charged with the admixture of the curable/castable explosive composition, and (ii) the curable/castable explosive composition is being cured or casted.

11. The process according to claim 10 , wherein the recess is formed based on the male former being in the location, while the curable/castable explosive composition is being cured or casted.

12. The process according to claim 1 , wherein charging the gap comprises:
charging the gap with the admixture of the curable/castable explosive composition, through an opening between the female mould and the male former.

13. The process according to claim 1 , wherein the recess has a shape that is substantially similar to a shape of a surface of the male former facing the female mould during said charging of the gap.

14. A moulding system for providing a pre-defined recess in a cured or cast explosive composition, the system comprising:
a female mould capable of receiving a curable/castable explosive composition;
a male former having an outer surface and an inner surface, wherein the male former comprises at least one fluid vent that extends between the outer and inner surfaces of the male former, and wherein a seal of the at least one fluid vent comprises a removable plug that is removable from the vent; and
a support to locate the male former proximate to the female mould in a location, to create a gap therebetween, to allow the formation of a pre-defined recess within said cured/cast explosive composition;
wherein, in use of the system, the gap is charged with the curable/castable explosive composition, and post cure/cast the male former is removed from proximate to the female mould to furnish a cured or cast explosive composition with the pre-defined recess;
wherein the support is further to retain the same location of the male former proximate to the female mould, while (i) the gap is being charged with the curable/castable explosive composition, and (ii) the curable/castable explosive composition is being cured/casted.

15. The moulding system according to claim 14 , wherein the male former comprises an inner surface and an outer surface, said outer surface contacts said curable/castable explosive composition, wherein said male former further comprises at least one vent hole, which allows the through flow of a fluid from an inner surface to an outer surface of said male former, and wherein the female mould comprises an energetic payload cavity of a munition.

16. A process for forming a pre-defined recess in a cured or cast explosive composition, the process comprising:
locating a male former proximate to a female mould to create a gap between said male former and female mould;
forming an admixture of a curable/castable explosive composition;
charging the gap with the admixture of explosive composition;
causing the cure or cast of said curable/castable explosive composition;
applying resonant acoustic stimulus at a frequency in the range of 20 Hz to 100 Hz to the female mould and/or male former; and
removing the male former to furnish a cured or cast explosive composition with a pre-defined recess.

17. The process according to claim 16 , wherein the male former comprises an outer surface, which contacts said curable/castable explosive composition, wherein said outer surface comprises a release agent coated thereon.

18. The process according to claim 16 , wherein the male former comprises at least one fluid vent, capable of the transfer of a fluid through the male former, said fluid causing ejection of the male former from the cured or cast explosive composition, wherein the at least one fluid vent is sealed during the charging, wherein the male former comprises an outer surface, and wherein the seal of the at least one fluid vent comprises a removable plug, which is flush fitting to the outer surface of the male former.

19. The process according to claim 16 , wherein:
the female mould is a payload cavity of a munition;
the curable/castable explosive composition comprises an explosive material, a polymerisable binder, and a cros

Assignees

• Bae Systems Plc

Inventors

• Redding Darren John
• Phillips Stuart Martin
• Davies Gavin Morgan
• Davies Benjamin Mark
• Wilson Robert John

Classifications

• B29C39/26 Primary

  Moulds or cores · CPC title

• B29C33/46

  using fluid pressure · CPC title

• B29C39/026

  characterised by the shape of the surface · CPC title

• C06B21/0058 Primary

  by casting a curable composition, e.g. of the plastisol type · CPC title

• F42B1/032

  characterised by the material of the liner · CPC title