Magnet-Based Pressure for Composite Core Splicing

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Solution Overview

Problem

Conventional methods for splicing and securing composite cores during machining and assembly processes are inefficient, leading to high scrap rates and difficulties in bonding flanges to substructures due to mechanical limitations and weight issues with expandable foam adhesives.

Innovation Solution

The use of magnets to apply pressure at the adhesive bondline by attracting ferrous elements, allowing for uniform clamping and precise bonding, and the manufacturing of net edge cores with tailored mandrels for improved surface bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If mechanical clips are used to apply pressure at the adhesive bondline, then pressure can be applied during splicing, but the spring force cannot be effectively transferred at large distances from the open edge and the clips interfere with tooling

Engineering Contradiction:
Improvepressure at bondlineVSAvoidtooling interference
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent replaces mechanical clips with magnets to apply pressure at the adhesive bondline. The magnets provide the necessary clamping force through magnetic attraction without physical contact, eliminating interference with machining tools while maintaining effective pressure application across the bondline.

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

2Device complexity

If expandable foam adhesive is used to avoid artificial pressure, then no mechanical pressure application is needed, but the adhesive becomes weight prohibitive

Engineering Contradiction:
Improvepressure application mechanismVSAvoidadhesive weight
Core Design Contradiction:
Device complexityVSWeight of moving object

Solution Approach 1:

The patent introduces magnets as an intermediary between the adhesive and the bonding surfaces. The magnets provide the necessary pressure for adhesive bonding without requiring the adhesive itself to generate pressure through expansion, thereby avoiding the weight penalty of expandable foam while still achieving effective bondline pressure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If composite core is machined to desired contour, then the core can be used in composite structures, but the natural instability of the composite core creates high scrap rates and requires low machine feed rates

Engineering Contradiction:
Improvecore contourVSAvoidscrap rate
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies magnets to secure the composite core to the tooling before machining begins. This preliminary securing action stabilizes the core during the machining process, preventing instability-related defects and reducing scrap rates without requiring reduced feed rates.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If flanges are left on composite core after carving, then the core can be manufactured from larger bulk, but the flanges are difficult to bond to adjacent substructure

Engineering Contradiction:
Improvecore manufacturingVSAvoidbonding surface quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses magnets to apply pressure during bonding of the core to the substructure. This magnetic pressure application enables effective bonding of flanged surfaces without requiring complex mechanical pressing systems, thereby maintaining ease of manufacture while achieving good bonding quality.

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 approach reduces scrap rates, enhances bonding efficiency, and allows for precise control over core dimensions and bonding surfaces, eliminating the need for mechanical devices and reducing waste by providing consistent pressure and increased bonding surface area.

Implementation Method 1

using magnets to apply pressure at the adhesive bondline by attracting ferrous elements

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentEP2886304B1Method of splicing composite core
Publication Date: 2016.04.20 BELL HELICOPTER TEXTRON INC
  • EP2886304B1 patent drawingFigure 1~2
  • EP2886304B1 patent drawingFigure 3~4
  • EP2886304B1 patent drawingFigure 5~6

AI summary

A method (401) of splicing together a first composite core (501, 601, 701, 901) and a second composite core (503, 603, 703, 903) can include: positioning a first flange (501a, 601a, 901a) of the first composite core (501, 601, 901), adjacent to a second flange (503a, 603a, 903a) of the second composite core (503, 603, 903) applying (405) an adhesive (507, 607, 707, 907, 1007, 1503, 1811, 2509), and locating (407) a first magnet (505a, 605a, 705a, 905a, 1005a, 1501a, 1809a, 2511a) and a second magnet (505b, 605b, 705b, 905b, 1005b, 1501b, 1809b, 2511b) to provide a pressure on the adhesive (507, 607, 707, 907, 1007, 1503, 1811, 2509).