Polyimide Preload Cable Assembly for Consistent Flyer Velocity

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Solution Overview

Problem

Existing exploding foil initiators face issues with inconsistent barrel thickness and production yield due to defects in injection molding, leading to suboptimal flyer velocity and detonation timing, and inefficient space utilization.

Innovation Solution

A preload cable with a polyimide substrate and laser-drilled hole for the barrel, along with fiducials for precise alignment, ensuring consistent dimensions and higher production yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If injection molding is used to form the barrel, then the barrel can be formed with cavities for fitting the bridge, but the production yield is low due to defects and inconsistent thickness

Engineering Contradiction:

Improvebarrel formation capabilityVSAvoidbarrel thickness consistency

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical injection molding process with a lamination process using polyimide layers. Instead of using molds to form the barrel with cavities, the barrel is constructed by laminating multiple polyimide layers together, which are then laser-drilled to create the necessary holes and cavities. This substitution eliminates the defects associated with injection molding while maintaining the structural requirements for bridge fitting.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the manufacturing parameters from injection molding temperature and pressure to lamination bonding parameters and laser drilling parameters. By controlling the lamination process and using laser drilling with precise positioning, the barrel thickness consistency is improved to within 0.002 inches, significantly better than injection molding capabilities.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If injection molding is used to form the barrel, then the barrel can be formed quickly, but the production yield is less than 10% due to defects

Engineering Contradiction:

Improvebarrel formation speedVSAvoidproduction yield

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces injection molding with lamination and laser drilling. The lamination process involves stacking polyimide layers and bonding them together, followed by laser drilling to create holes. This process eliminates the defects inherent in injection molding (such as warping, voids, and inconsistent thickness) while maintaining high production speed through automated layer stacking and continuous laser processing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses composite construction by laminating multiple polyimide layers to form the barrel. This composite approach provides both mechanical strength and dimensional stability, while the uniform polyimide material ensures consistent thermal and electrical properties throughout the barrel structure, eliminating the variability associated with injection molded parts.

Inventive Principle:

Principle #40Composite materials

3Speed

If the barrel thickness is varied to adjust flyer velocity, then the detonation timing can be controlled, but the production yield decreases due to alignment issues in molding

Engineering Contradiction:

Improveflyer velocity controlVSAvoidbarrel-cavity alignment

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The patent incorporates fiducial markers during the lamination process that are used for precise alignment during subsequent assembly steps. These fiducials are created on the polyimide layers before final assembly, allowing for accurate positioning of the bridge and other components relative to the barrel holes, eliminating alignment issues that plague injection molding processes.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical mold alignment with laser-based positioning and fiducial alignment. The laser drilling process uses the fiducial markers to automatically position holes with high precision, and the overall assembly process uses fiducial alignment rather than mechanical fit-up, achieving consistent alignment without the defects of mold-based systems.

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

The solution provides a durable, electrically and thermally resistant barrel with improved alignment, resulting in higher production yields and consistent flyer velocity for reliable detonation.

Implementation Method 1

cutting a hole in the first substrate; ablating, via the laser, a portion of the first substrate to form a fiducial

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

ablating, via the laser, a portion of the first substrate to form a fiducial

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS12529547B1Preload cable, detonator cable assembly, and methods of making the same

Publication Date: 2026.01.20 HONEYWELL FEDERAL MANUFACTURING & TECHNOLOGIES LLC

AI summary

A preload cable comprises a cable, a first substrate, a bridge, a flyer, and a second substrate. The cable includes a pair of contacts. The first substrate includes a pair of conductors connected to the contacts. The bridge is positioned on the first substrate and is connected to the conductors. The flyer is positioned on the bridge. The second substrate is positioned adjacent to the first substrate and comprises a polyimide layer, and a hole extending through the polyimide layer and in alignment with the flyer.