Composite Feature Formation Mandrel Compaction Matching

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Solution Overview

Problem

Forming features in composite materials during the laminating process is challenging as it can introduce anomalies like kinks in the plies and air pockets, degrading the performance of the finished piece, and post-cure machining poses a risk of damage.

Innovation Solution

A method involving laying composite layers on a tool surface, removing parts to create mandrels that conform to the desired features, and re-laying layers over these mandrels for curing, ensuring the mandrels match the compaction rate of the removed parts, thus avoiding kinks and air pockets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If features are formed by post-cure machining, then manufacturing flexibility is improved, but the risk of damage to the composite piece increases

Engineering Contradiction:

Improvemanufacturing flexibilityVSAvoidrisk of damage

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The mandrel is inserted into the laminate stack before curing, pre-defining the feature geometry. This preliminary action allows the feature to be formed during the laminating process itself, eliminating the need for post-cure machining and thereby reducing the risk of damage while maintaining manufacturing flexibility

Inventive Principle:

Principle #10Preliminary action

2Productivity

If features are pre-formed during laminating, then post-cure manufacturing operations are reduced, but anomalies such as kinks and air pockets are introduced

Engineering Contradiction:

Improvereduction of post-cure operationsVSAvoidanomalies in laminate

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The mandrel is designed to have substantially the same rate of compaction during curing as the surrounding composite layers. By matching this critical parameter, the mandrel moves in harmony with the laminating process, preventing the formation of kinks and air pockets while still enabling feature formation during lamination

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The mandrel material is selected to have compaction characteristics homogeneous with the composite layers. This ensures uniform deformation behavior during curing, eliminating interfaces where anomalies could form and maintaining manufacturing precision while improving productivity

Inventive Principle:

Principle #33Homogeneity

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 reduces the occurrence of kinked laminate layers, burrs, and air pockets, enhancing the accuracy and reliability of the manufacturing process by allowing features to be formed without compromising the integrity of the composite piece.

Implementation Method 1

The composite material may comprise a thermoplastic resin and the curing step may comprise the setting of the thermoplastic resin

Methodology Applied

Scientific EffectThermoplastic setting: Phase Change

Data Source

PatentUS7981241B2Method for forming a feature in a piece of composite material

Publication Date: 2011.07.19 AIRBUS OPERATIONS LTD

AI summary

A method of forming a piece from a composite material is disclosed in which a mandrel is used that reduces relative movement between the mandrel and the piece during the curing process.