Warhead Inner Shell Assembly for Fast Projectile Fixing

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Solution Overview

Problem

Existing methods for producing warhead components with pre-formed projectiles are time-consuming, costly, labor-intensive, and pose occupational health and safety issues, with limited flexibility and high development times due to the use of rubber fixtures and machining grooves.

Innovation Solution

A method involving an inner shell with recesses for pre-formed projectiles, encased by polymer casings, followed by hot isostatic pressing to fix the projectiles, and subsequent application of metal powder, which vaporizes the casings, allowing for faster, cheaper, and safer production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If rubber fixtures are used to arrange pre-formed projectiles during manufacturing, then the projectiles can be positioned and arranged, but the production process becomes time-consuming, costly, and labor-intensive with limited flexibility

Engineering Contradiction:
Improveease of arranging pre-formed projectilesVSAvoidproduction speed
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies preliminary action by pre-forming the shell body with integrated recesses and cavities during the shell casting process, before the arrangement of pre-formed projectiles. This eliminates the need for separate rubber fixtures and subsequent machining operations, allowing projectiles to be directly placed in their final positions and reducing overall manufacturing time and cost.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges the shell body formation with the projectile arrangement structure by integrating recesses and cavities directly into the shell body during casting. This combines what were previously separate operations (shell manufacturing and projectile positioning structures) into a single integrated process, eliminating the need for rubber fixtures and reducing production steps.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If rubber fixtures are used to arrange pre-formed projectiles, then positioning is achieved, but new product development and modifications require new rubber molding tools resulting in long lead times and high costs

Engineering Contradiction:
Improveease of arranging pre-formed projectilesVSAvoidflexibility for new product development
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The shell body is pre-formed with integrated recesses and cavities during the standard shell casting process, before projectile arrangement. This preliminary integration of positioning structures allows for easy modification of projectile arrangements by simply changing the casting pattern or adding different inserts, without requiring new rubber molding tools for each product variation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The shell body structure with integrated recesses and cavities serves multiple functions: it forms the protective shell, provides positioning structures for pre-formed projectiles, and allows for easy adaptation to different projectile configurations. This universal structure can accommodate various projectile types and arrangements by modifying the casting process rather than requiring dedicated fixtures for each configuration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If grooves are machined in the warhead material to achieve controlled fragmentation, then fragmentation control is achieved, but the process becomes difficult and labor-intensive

Engineering Contradiction:
Improvecontrolled fragmentationVSAvoidease of machining grooves
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The fragmentation control features (recesses, cavities, and weak points) are incorporated into the shell body during the initial casting process, before any machining or projectile arrangement operations. This preliminary formation of fragmentation structures eliminates the need for subsequent difficult and labor-intensive groove machining, while maintaining precise control over fragmentation patterns.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges the shell forming operation with the creation of fragmentation control features by integrating recesses, cavities, and weak point structures directly into the shell casting process. This combines what were previously separate operations (shell manufacturing and fragmentation feature creation) into a single casting operation, eliminating the need for subsequent machining.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of manufacture

If pre-formed projectiles are arranged using traditional methods, then the warhead can be assembled, but the process is costly and poses occupational health and safety issues

Engineering Contradiction:
Improveease of assembling warheadVSAvoidoccupational health and safety risks
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The shell body is pre-formed with integrated positioning recesses and cavities during casting, before projectile arrangement. This preliminary preparation creates a safe and easy workspace where pre-formed projectiles can be directly placed into designated positions without requiring complex fixtures or hazardous operations, reducing both cost and safety risks.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the positioning function from separate rubber fixtures and integrates it directly into the shell body structure through casting. This eliminates the need for additional fixtures and simplifies the assembly process, making it safer and less costly by removing unnecessary components and steps from the manufacturing process.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Facilitates faster, cheaper, and safer production of warhead components with improved working conditions, retaining the ability to customize projectile characteristics.

Implementation Method 1

followed by hot isostatic pressing to fix the projectiles

Methodology Applied
Scientific EffectHot isostatic pressing: Hot Isostatic Pressing

Implementation Method 2

subsequent application of metal powder, which vaporizes the casings

Methodology Applied
Scientific EffectVaporization: Evaporation

Data Source

PatentEP4341637B1A method for producing a warhead component
Publication Date: 2026.01.28 BAE SYSTEM BOFORS AB
  • EP4341637B1 patent drawingFigure 1~2
  • EP4341637B1 patent drawingFigure 3~4
  • EP4341637B1 patent drawingFigure 5

AI summary

This invention relates to a method for producing a warhead component comprised of an inner shell, characterized in that the method comprises the following steps: i.) a first casing of a thermoplastic is arranged to enclose the inner shell, ii.) pre-formed projectiles are arranged between the first casing of thermoplastic and the inner shell, iii.) the first casing is heat-treated so that the first casing shrinks and fixes the pre-formed projectiles to the inner shell. The invention further relates to a warhead, to a projectile, and to a bomb.