Cold-Sprayed Bomb Casing Structure With Low Thermal Distortion

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Solution Overview

Problem

Conventional warhead casing manufacturing methods, such as casting and forging, are limited by tooling requirements, high energy consumption, and restricted design flexibility, leading to increased costs and reduced efficiency in developing new designs, while additive manufacturing methods like directed energy deposition suffer from thermal distortion issues.

Innovation Solution

The use of cold-gas dynamic spraying to additively manufacture bomb casings, specifically a conical nose and cylindrical body, with integral construction, allowing for uniform metal properties and customizable features like rupture seams, using high-strength steel alloys and controlled deposition parameters to achieve desired mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional casting or forging methods are used to manufacture bomb casings, then the mechanical properties and hardness can be achieved, but the design flexibility is restricted and tooling requirements increase costs and development time

Engineering Contradiction:
Improvedesign flexibilityVSAvoidtooling requirements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the fundamental manufacturing parameter from subtractive (molding/forging with fixed tooling) to additive (layer-by-layer deposition), enabling design flexibility without tooling constraints. The additive manufacturing process allows arbitrary geometric parameters to be modified through software rather than requiring physical tooling changes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical tooling system (molds, dies, fixtures) with a digital modeling and robotic deposition system. This substitution eliminates the need for physical tooling while maintaining manufacturing capability, directly resolving the contradiction between design flexibility and tooling complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If conventional casting or forging methods are used to manufacture bomb casings, then the mechanical properties can be achieved, but the energy consumption is significant and production efficiency is reduced

Engineering Contradiction:
Improveproduction efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent extracts the high-energy steps (melting, extensive machining) from the manufacturing process and replaces them with low-energy additive deposition. Material is deposited in near-net-shape layers, eliminating the need for energy-intensive melting and removal of large amounts of material through machining.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The additive manufacturing process enables continuous deposition of material layer-by-layer without interruption for tooling changes or setup. This continuous production approach eliminates downtime associated with conventional batch processing, molds, and fixtures, thereby improving productivity while reducing overall energy consumption.

Inventive Principle:
Principle #20Continuity of useful action

3Adaptability or versatility

If directed energy deposition additive manufacturing is used to manufacture bomb casings, then design flexibility is improved, but thermal distortion occurs due to concentrated heat application

Engineering Contradiction:
Improvedesign freedomVSAvoidthermal distortion
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent introduces a robotic positioning system and computer-controlled deposition head as intermediaries between the design software and the physical manufacturing process. This intermediary system enables precise control of deposition parameters, travel speed, and layer placement, thereby compensating for thermal effects and maintaining manufacturing precision while preserving design freedom.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces conventional high-heat melting processes with a controlled additive deposition process where material is deposited and bonded layer-by-layer. This substitution reduces concentrated thermal input while maintaining design flexibility through digital modeling and programmable robotic deposition.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method enables cost-effective, efficient production of casings with enhanced mechanical properties, reduced thermal distortion, and design flexibility, facilitating rapid prototyping and mass production with improved penetrative and fragmentation performance.

Implementation Method 1

The additive manufacturing process is cold-gas dynamic spraying of metal particles onto a support member

Methodology Applied
Scientific EffectCold-gas dynamic spraying: Fluid Spray

Data Source

PatentEP4348161B1Additively manufactured bomb casing
Publication Date: 2026.02.04 COMPOSITE TECH R & D PTY
  • EP4348161B1 patent drawingFigure 1
  • EP4348161B1 patent drawingFigure 2~3
  • EP4348161B1 patent drawingFigure 4~5

AI summary

An embodiment of the bomb casing (1) defines a generally conical nose portion (2) and a cylindrical body portion (3). At least one, and more preferably both, of the generally conical nose portion (2) and/or the cylindrical body portion (3) are formed from an additive manufacturing process, which is preferably cold-gas dynamic spraying of metal particles onto a support member. In one embodiment, the generally conical nose portion and cylindrical body portion are integrally formed.