Integrated additive manufacture (AM) of explosive payloads
Integrated Additive Manufacture (AM) of explosive payloads including both energetic and non-energetic components is achieved by controlling the AM processes such that a temperature of any deposited energetic material is bounded below and away from the energetic material's onset temperature to avoid detonation or decomposition of the energetic material during manufacture. This constraint places requirements on the selection of the energetic materials, the AM processes and 3D printer systems for depositing the non-energetic materials and the final composition and density of the non-energetic components.
1 . A method of manufacturing an explosive payload, the method comprising:
using one or more additive manufacturing processes to selectively deposit energetic and non-energetic materials in a layer-by-layer sequence to build at least one energetic component and at least one non-energetic component, in which a first portion of at least one said non-energetic component and a first portion of at least one said energetic component are built in a common layer and a second portion of at least one said non-energetic component is built on a top surface of a second portion of at least one said energetic component, wherein the energetic material has an onset temperature at which the energetic material may detonate; and
controlling the additive manufacturing process that is used to build the at least one said non-energetic component such that a temperature of any deposited energetic material is bounded below and away from the energetic material's onset temperature to avoid detonation or decomposition of the energetic component during manufacture.
2 . The method of claim 1 , further comprising controlling the additive manufacturing process such that the temperature of any deposited energetic material is bounded below and away from the energetic material's onset temperature by minimum 50 degrees C.
3 . The method of claim 1 , further comprising controlling additive manufacturing process such that a maximum temperature of the process is less than the energetic materials' onset temperature.
4 . The method of claim 1 , further comprising using the additive manufacturing process to form an insulating layer on the top surface of the second portion of the at least one said energetic component between the second portion of said energetic component and the second portion of the at least one said non-energetic component.
5 . The method of claim 1 , further comprising controlling the additive manufacturing process to add a polymer binder to the non-energetic material for selective deposition and to forego sintering at temperatures above the onset temperature to remove the polymer binder after deposition thereby leaving a non-zero percentage of polymer binder in the at least one non-energetic component.
6 . The method of claim 5 , further comprising controlling the additive manufacturing process to selectively deposit non-energetic material including the polymer binder to from a non-energetic component prior to the deposition of any energetic material, further comprising controlling the additive manufacturing process to sinter the non-energetic component to remove the polymer binder.
7 . The method of claim 1 , wherein the non-energetic material includes a polymer binder having a deposition temperature that is bounded below and away from the energetic material's onset temperature.
8 . The method of claim 7 , wherein the energetic material is a PBX material selected from HMX and HNS.
9 . The method of claim 1 , wherein the additive manufacturing process used to build the at least one non-energetic component is selected from direct pellet extrusion (DPE), fused filament fabrication (FFF), stereolithography (SLA), direct write (DW) syringe and slurry-based screw extrusion.
10 . The method of claim 1 , wherein the additive manufacturing process used to build both the at least one energetic component and the at least one non-energetic component is direct pellet extrusion (DPE).
11 . The method of claim 10 , wherein a single 3D printing system is configured for FDM, a first printer head is configured and heated within a temperature range less than the onset temperature of the energetic material to deposit the energetic material, a second printer head is configured and heated within a temperature range greater than the onset temperature of the energetic material to deposit the non-energetic material.
12 . The method of claim 1 , wherein a single 3D printing system is configured with a plurality of printer heads for different additive manufacturing processes to build the at least one energetic component and the at least one non-energetic component.
13 . The method of claim 1 , wherein a first 3D printing system is configured for a first additive manufacturing process to build the at least one energetic component, a second 3D printing system is configure for a second additive manufacturing process to build the at least one non-energetic component, wherein the explosive payload is moved back-and-forth on a stage between the first and second 3D printing systems to build the explosive payload.
14 . The method of claim 1 , wherein the additive manufacturing processes builds the at least one energetic component to include an internal booster charge and a main charge each formed from an energetic material having an onset temperature, further comprising controlling the additive manufacturing process such that the temperature of any deposited energetic material is bounded below and away from the lowest onset temperature.
15 . The method of claim 14 , wherein the explosive payload is a fragmentation warhead and the internal booster charge is positioned axially at the center of the main charge, wherein the additive manufacturing processes build a casing as the non-energetic component and the internal booster charge and main charge layer-by-layer.
16 . The method of claim 14 , wherein the explosive payload is a shaped charge warhead and the internal booster charge is positioned axially in line with the main charge, wherein the additive manufacturing processes build a shaped-charge liner and a casing as the non-energetic components and the main charge and internal booster charge layer-by-layer.
17 . The method of claim 16 , wherein the shaped charge liner is formed prior to any energetic material for the main charge or internal booster charge, wherein the non-energetic material used for the shaped charge liner includes a polymer binder, further comprising:
sintering the shaped charge liner at a temperature above the energetic material's onset temperature to remove polymer binder and increase the density of the shaped-charge liner.
18 . The method of claim 14 , wherein the explosive payload is a penetrating warhead and the internal booster charge is positioned axially in line with the main charge, wherein the additive manufacturing process builds a penetrator and a casing as the non-energetic components and the main charge and internal booster charge layer-by-layer.
19 . The method of claim 18 , wherein the penetrator is formed prior to any energetic material for the main charge or internal booster charge, wherein the non-energetic material used for the penetrator includes a polymer binder, further comprising:
sintering the penetrator at a temperature above the energetic material's onset temperature to remove polymer binder and increase the density of the penetrator.
20 . An explosive payload, comprising:
at least one energetic component formed from at least one energetic material, said at least one energetic material having an onset temperature at which it may detonate,
at least one non-energetic component formed from at least one inert material,
wherein a first portion of the at least one non-energetic component and a first portion of the at least one energetic component are formed in a common layer;
wherein a second portion of the at least one non-energetic component is formed on a top surface of a second portion of the at least one energetic component;
wherein the at least one energetic component and at least one non-energetic component are created via one or more additive manufacturing processes to selectively deposit energetic and non-energetic materials in a layer-by-layer sequence;
wherein the additive manufacturing process that is used to build the at least one said non-energetic component is controlled such that a temperature of any deposited energetic material is bounded below and away from the energetic material's onset temperature to avoid detonation or decomposition of the energetic component during manufacture.