Tooling Mandrel Fluid Passage Network for Composite Extraction

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Solution Overview

Problem

The removal of a tooling mandrel from a composite laminate cavity after curing is hindered by high-stick friction, requiring excessive extraction force due to resin deposits between the mandrel and the laminate, which is undesirable for both the composite structure and the mandrel.

Innovation Solution

A tooling mandrel with a fluid passage network that promotes thermal conductance and changes its cross-sectional shape to facilitate removal, featuring primary and secondary flow passages and a fluid interface for supplying a fluid medium to control thermal contraction and break high-stick friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a tooling mandrel is used to support the composite laminate cavity during curing, then the composite structure can be properly formed under compaction pressure, but high-stick friction develops at the interface between the mandrel and laminate, requiring excessive extraction force for mandrel removal

Engineering Contradiction:

Improvecomposite structure formationVSAvoidextraction force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent changes the physical parameters of the mandrel by incorporating a fluid passage network that enables thermal contraction. By circulating cooling fluid through the passages, the mandrel temperature is reduced, causing it to contract dimensionally. This parameter change (temperature and dimension) reduces the extraction force needed to overcome high-stick friction at the mandrel-laminate interface.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the purely mechanical extraction system with a thermally-assisted system. Instead of relying solely on mechanical pulling force to overcome friction, the system uses thermal energy (cooling fluid circulation) to induce mandrel contraction, thereby reducing the mechanical extraction force required.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If a large extraction force is applied to overcome high-stick friction, then the mandrel can be removed from the composite laminate, but both the cured composite structure and the tooling mandrel may be damaged

Engineering Contradiction:

Improvemandrel removalVSAvoidcomposite structure and mandrel integrity

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

By changing the temperature parameter of the mandrel through the fluid passage network, the patent reduces the frictional resistance at the interface. This parameter change enables mandrel removal with lower extraction force, thereby preventing damage to both the composite structure and the mandrel while maintaining ease of operation.

Inventive Principle:

Principle #35Parameter changes

3Force

If the mandrel cross-sectional area is reduced to facilitate removal, then extraction force is reduced, but the mandrel may not provide sufficient support during the cure cycle

Engineering Contradiction:

Improveextraction forceVSAvoidcompaction pressure support

Core Design Contradiction:

ForceVSStress or pressure

Solution Approach 1:

The patent applies parameter changes dynamically: the mandrel maintains its full cross-sectional area at operating temperature to provide adequate compaction pressure support during curing. After curing, the mandrel is cooled through the fluid passage network, causing thermal contraction that reduces its effective cross-sectional area and the extraction force required for removal. This temporal separation of functions resolves the contradiction between support capability and ease of removal.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The mandrel's effective dimensions are made dynamic through thermal expansion and contraction. During curing, the mandrel is hot and expanded, providing maximum support. During extraction, the mandrel is cooled and contracted, reducing extraction force requirements. This dynamic behavior allows the same mandrel to satisfy both contradictory requirements at different times in the process.

Inventive Principle:

Principle #15Dynamics

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 method and apparatus reduce the extraction force needed to remove the mandrel by creating vertex gaps through controlled thermal contraction, thereby reducing high-stick friction and enabling easier mandrel extraction with less force.

Implementation Method 1

The fluid passage network may have a passage cross-sectional area shaped to promote thermal conductance between the fluid medium and the tooling mandrel and cause a change in a mandrel cross-sectional shape to facilitate removal of the tooling mandrel from the composite laminate cavity

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Implementation Method 2

The fluid passage network may have a passage cross-sectional area shaped to promote thermal conductance between the fluid medium and the tooling mandrel

Methodology Applied

Scientific EffectThermal conductance: Conduction (thermal)

Data Source

PatentUS10807280B2Method of extracting a tooling mandrel from a composite laminate cavity

Publication Date: 2020.10.20 THE BOEING CO

AI summary

A tooling mandrel for manufacturing a composite structure may include a mandrel body having a fluid passage network formed within the mandrel body for passing a fluid medium through the mandrel body. The fluid passage network may have a passage cross-sectional area shaped to promote thermal conductance between the fluid medium and the tooling mandrel and cause a change in a mandrel cross-sectional shape.